Contingency Planning for Disaster Risk Reduction:
agronomic, engineering other non-engineering interventions for drought, flood,
cyclone and heat/cold waves, agro- met advisories, crop advisories, community
nursery, contingent seed bank, mini-kit availability
Contingency planning
Contingency planning aims to
prepare an organization to respond well to an emergency and its potential
humanitarian impact. Developing a contingency plan involves making decisions in
advance about the management of human and financial resources, coordination and
communications procedures, and being aware of a range of technical and
logistical responses. Such planning is a management tool, involving all
sectors, which can help ensure timely and effective provision of humanitarian
aid to those most in need when a disaster occurs. Time spent in contingency
planning equals time saved when a disaster occurs. Effective contingency
planning should lead to timely and effective disaster-relief operations.
The contingency planning process can basically
be broken down into three simple questions:
• What is going to happen?
• What are we going to do about it?
• What can we do ahead of time to get prepared?
This guide helps planners
think through these questions in a systematic way. Contingency planning is most
often undertaken when there is a specific threat or hazard; exactly how that
threat will actually impact is unknown. Developing scenarios is a good way of
thinking through the possible impacts. On the basis of sensible scenarios it is
possible to develop a plan that sets out the scale of the
response and the resources needed.
Our new Contingency planning guide breaks
contingency planning down into five main steps, shown in the diagram below.
Each step is covered by a separate chapter in the guide.
In order to be relevant and useful, contingency
plans must be a collaborative effort. They must also be linked to the plans,
systems or processes of other government, partner or Movement bodies at all
levels – national, regional and global. There is a suggested format for
contingency plans annexed to the guide and also a collection of training
modules available from the IFRC.
Overview
Contingency planning (also referred to as response
planning) is a critical activity for organizations and communities to prepare
themselves to respond well to a disaster event and its potential impacts.
Developing a contingency plan involves making
decisions in advance about the management of human, financial, and material
resources and of coordination and communications procedures to ensure timely
and effective provision of assistance and humanitarian aid to those most in
need when a disaster occurs. Time invested in contingency and response planning
pays dividends in reduced damage and loss of life and more effective delivery
of response and recovery services.
Contingency planning is one component of a much
broader emergency preparedness process and is included within business
continuity programing alongside operational continuity, disaster recovery
planning, policy creation, established processes, and more.
Analysis
of data from Ethiopia and India suggests that in areas “where drought is a
major risk, it is also the single most important factor in
impoverishment—outstripping for example ill health and dowry payments”
(Shepherd et al. 2013, x). Therefore, implementation of disaster risk
management is critical to successfully eliminate poverty and improve food
security in these regions. The goals of this report were to review the drivers
of vulnerability to drought in East Africa and in the western Indo-Gangetic
Plain of South Asia, to explore options to increase the resilience of farming
communities, and to present both opportunities and obstacles to the development
and adoption of drought risk reduction measures. Drought risk reduction must
focus not only on saving lives but also on saving livelihoods, by reducing
vulnerability to hazards and by supporting asset building before and after an
extreme event has taken place (Shepherd et al. 2013). Moreover, because droughts
in East Africa and IGP are not necessarily localized in space and time, as they
may be more of a recurrent phenomenon, disaster risk management should be
emphasized as an integral part of development work. By now, we possess a wealth
of evidence, accumulated from modeling studies and work in the field, about the
benefits of different agricultural technologies and practices in mitigating
drought (Rosegrant et al. 2014). Complementary interventions, like safety nets
and insurance programs, are also proving to be effective in building resilience
and reducing drought risk. More and more often, national and local governments
have access to relevant knowledge, information, and tools and techniques—but
this material needs to be delivered to the places and people who need it most.
Research shows that in SSA and in South Asia, access to innovation, knowledge,
and input and output markets continues to be the most important constraint to
investments in agriculture, and therefore to development of irrigation and adoption
of other agricultural practices relevant to drought risk reduction (GDN and
Babel Press 2013b). Governments, NGOs, the private sector, and aid agencies
continue to have very important roles to play to overcome these constraints and
increase the resilience of farmers to drought events. Governments can set up
farmer schools and must invest in infrastructure, organize and modernize
extension services to promote the most appropriate resource-saving practices,
and improve the multiplication of stress-resistant seed varieties, in
cooperation with the private sector. We have some encouraging examples. The
government of Ethiopia put together the PSNP social protection scheme, helping
food-insecure households to build their assets, by providing education on new
cultivation techniques and production diversification, and by setting up a
monitoring system that checks whether households are building both individual
and communal assets. The government in Kenya was able to coordinate with the
private sector to multiply seeds, and facilitated the award of loans and credit
by building the knowledge and skills34 of farmers (GDN and Babel Press 2013d).
In many instances, especially where the government reach was inadequate, NGOs
have stepped in to support the diffusion of improved seeds, instruct farmers on
crop and livestock diversification, and promote the adoption of new
agricultural techniques and practices through farmers’ education programs.
Moreover, across South Asia and SSA, NGOs, alone or in cooperation with financial
institutions, government bodies, and international aid organizations, are
tackling farmers’ constraints by using microfinancing to push forward adoption
of fertilizers and improved crop varieties. In some instances they offer
packages that include crop insurance; some work is also being done on adding
items such as chlorine dispensers for clean drinking water, a useful step
toward tackling public health issues that increase vulnerability of farming
communities (Thurow 2012). And governments, NGOs, the private sector (for
example, cell phone communications), and financial institutions have come
together to facilitate the diffusion of weather index insurance. In India the
private sector is intervening directly in some situations to fill some of the knowledge
and technology gaps by providing farmers with training on new practices. They
invest in capacity to ensure a steady flow of product for their commercial
activities, and in doing so they also facilitate the farmers’ access to markets
(GDN and Babel Press 2013c). These are examples of how different institutions
can help farmers adopt best practices and technologies, improve their
productivity, build their assets, and thus dramatically reduce their
vulnerability to shocks. But agriculture is still a high-risk endeavor in both
South Asia and SSA. More work is needed in many areas; for instance,
cooperation with the private sector for seed multiplication is still
inadequate, and technology and knowledge dissemination must be strengthened.
One of the ways forward may be to redirect some of the financing for food aid
and post disaster relief to investments in development and resilience building.
The example of MERET in Ethiopia shows that a gradual transition between the
two is possible. Although the use of food aid to encourage work is still
controversial, the experience of MERET demonstrates that the approach can be
used to promote development and build resilience against drought; food aid can
then be phased out in exchange for more technical assistance and for loans
(Nedessa and Wickrema 2010). Institutions like governments, NGOs, and
international organizations may help build farmers’ resilience also through
another route. Collectivization, the formation of farmers associations, and in
general the formal or informal organization of individuals in a group of some
kind, has historically helped farmers to manage risk, including by facilitating
the adoption of new technologies and new skills, and helping with access to
markets and credit, thereby promoting the accumulation of assets and reducing
vulnerability to shocks (Bernier and Meinzen-Dick 2014). However, these
organizations are often less able to cope with covariate shocks35 such as
droughts or floods. Research on collective action and local groups suggests
that external support, such as links with higher-level organization (for
example, government, international organizations, NGOs) may allow groups to
increase their efficacy (Di Gregorio et al. 2012). Drought risk reduction and
improvement of resilience is a process; as such it requires long-term
commitments from governments and from the research and development community.
Single projects cannot transform a society and its resilience. What is needed
is long-term support to learning and capacity building, and investments to
cultivate the capacity for disaster risk reduction across farming communities.
Building social capital and changing behavior are critical bases to ensure
resilience against weather shocks for the long term.
(1) Unproductive water losses such as evaporation and
runoff increase from continental in-season rainfall climates to
storage-dependent winter rainfall climates. Highest losses occur under tropical
residual moisture regimes with short intense rainy season. (2) Sites with a
climatic dry season require adaptation via phenology and water saving to ensure
stable yields. Intermittent droughts can be buffered via the root system, which
is still largely underutilised for better stress resistance. (3) At short-term
better management options such as mulching and date of seeding allow to adjust
cropping systems to site constraints. Adapted cultivars can improve the
synchronisation between crop water demand and soil supply. At long term, soil
hydraulic and plant physiological constraints can be overcome by changing
tillage systems and breeding new varieties with higher stress resistance. (4)
Interactions between plant and soil, particularly in the rhizosphere, are a way
towards better crop water supply.
Water scarcity is
considered a key threat for the twenty-first century (UNESCO 2012).
FAO defines drylands as areas where water shortage constrains the length of the
growing season below 179 days (FAO 2000);
this includes regions classified climatically as arid, semi-arid and dry
subhumid. On average, 40 % of the world’s land surface are drylands,
ranging from 89 % in Oceania to 24 % in Europe. Cultivated land makes
up 25 % of total dryland area, decreasing from 47 % in dry subhumid
to 0.6 % in hyper-arid regions. Currently, 36 % of the world
population is living in regions where water is a limited resource (Safriel et
al. 2005). Agriculture is
by large the dominant user of fresh water, except for Europe (22 %) and
North America (38 %), accounting for up to 90 % of total water
consumption in some regions (FAO 2004b;
Hoekstra and Mekonnen 2012).
When projecting the current trend of global annual water usage, it will rise to
6.9 trillion cubic metres by 2030, being 40 % more than can be provided by
available water supplies (Gilbert 2010).
Sposito (2013) highlighted that
both land conversion for crop cultivation as well as water use for croplands
are approaching their planetary limits. Therefore, he pointed to the need for
new approaches to enhance water productivity by making use of plant–soil
interactions.
Crop ecology
studies the environmental properties and processes in the soil–plant–atmosphere
continuum (SPAC) that determine the productivity of a cropping system, and how
the use of available growth factors can be optimised (e.g. Swaminathan 2006;
Connor et al. 2011). In the
particular context of water management, crop ecology links the analysis of (1)
the hydrological situation driven by climate and soil and (2) the physiological
response of the plant in order to provide management strategies for optimum
water supply to and efficient use by the crop.
Cropping systems
are ecosystems with strong anthropogenic forcing. There are two main
distinctions between a cropping system and a natural ecosystem. First, the
variable of interest is clearly focussed on yield in a cropping system, while
in a natural ecosystem, particularly in a stress environment, survival and
reproductive success could actually contradict maximum biomass productivity.
This has strong implications as easily exemplified in the context of drought
resistance: A range of resistance mechanisms (e.g. small leaf surface, membrane
stability) were described from natural vegetation where they allow survival and
reproduction under harsh drought stress. Although highly effective, they are
irrelevant for a water-efficient cropping system because of their
incompatibility with high yields. Crop production requires a minimum site
productivity, while survival mechanisms of xerophytic vegetation confer
superior growth mostly under stress beyond the limit of rainfed agriculture
(Blum 2005). Second, the key
interest of crop ecology is to understand which properties and processes in the
natural system can be most efficiently manipulated for a better performance of
crops within the given environmental constraints (e.g. climate, soil texture).
Contrary to an ecological approach to natural ecosystems, here, system
components are conceived as changeable by human activity. However, crop ecology
is still situated in the general field of ecology: The cropping system is not a
technical environment without natural constraints, but an ecosystem that
requires profound understanding of its physical, chemical, and biological
functioning to allow sustainable productivity.
Larcher (1994)
provides data of net primary productivity (NPP) of different ecosystems.
Cropping systems (0.65 kg m−2 a−1) are in
the range of sclerophyll savanna vegetation (0.7–0.9 kg m−2 a−1).
There is a tight relation of NPP and leaf area index where both cropping
systems and savanna vegetation have similar values (4 m2 m−2).
This suggests that, in many environments, agricultural productivity is not
primarily limited by natural boundaries, but by an inefficient use of available
growth factors such as light, water, and nutrients. Rockström et al. (2007)
give an example how yield levels in semi-arid sub-Saharan Africa could be
doubled by simply reducing the current level of high runoff and evaporation
losses. This points to the key importance of detailed ecological understanding
of cropping systems to obtain an optimum use of available growth factors.
With an overall
focus on high crop productivity in water-limited ecosystems, the key questions
from a crop ecological point of view can be stated as follows: How much
improvement in crop water use is feasible, and what is the most efficient
management change to achieve it within the site-specific environmental
constraints? The principal objective of this review is to establish a relation
between drought regime and efficient crop water management measures. Tardieu (2012)
stated that any trait can confer drought resistance to a crop; it is just a
matter of designing the right drought scenario. It is therefore imperative to
understand the specific ecology of drought in a region to design an efficient
cropping system. The second objective of this review is to identify areas of
plant water use that are still poorly understood by crop sciences and therefore
underutilised in cropping system management. In this context, we put an
emphasis on dynamic plant–soil interactions, which special regard on the root
zone (Fig. 1), and discuss
challenges how to bridge the gap between scientific advances at small scales of
observation to the overall cropping system.
Drought resistance
in natural vegetation is an evolution towards ensuring of reproductive success.
In agricultural species, success is tightly bound to productivity, i.e.
maximisation of biomass and/or grain quantity. This implies that adequate
strategies of drought resistance differ.
Blum (2005, 2009)
demonstrated that yield compatible drought resistance strategies for
agricultural species avoid tissue dehydration, particularly by effective use of
water, while drought tolerance in a strict sense, i.e. physiological
functioning under low tissue water potential, is less relevant due to the
immediate reduction of growth when turgor pressure decreases. Yield improvement
by drought resistance mechanisms depends strongly on the drought regime (van
Ginkel et al. 1998; Blum 2011;
Tardieu 2012) Phenological
adaptation (drought escape) by early maturity, e.g. might cost vegetation time
in early drought environments, while being effective in summer–dry regions.
Dehydration avoidance by “water saving” might result in suboptimal use of
available water, while in other situations, a “conservative” water use may save
water for grain filling and yield formation (Mori et al. 2011).
Figure 7 shows the
potential role of different stress resistance strategies under the three
distinctive stress regimes described
Short-term measures
3.4.1 Mulching
Tillage systems modify soil
surface properties by different degree of soil coverage. Soil coverage can be
achieved by crop residues (mulching), a living canopy cover (cover cropping,
relay intercropping) or non-crop mulch material (plastic foil, geo-textile).
Soil coverage is intended to reduce runoff and evaporation from bare soil
surfaces. The respective importance of these two loss terms in different
climates was discussed in Section 3.2 and
resumed in Fig. 4.
For supply-driven conditions, Kálmar et al. (2013) studied post-harvest mulching
on a chernozem soil in central Hungary with annual rainfall of 580 mm and
mean temperature of 10 °C. They measured 8–11 % higher soil water
content in 0–65 cm soil depth for undisturbed mulch covered soil with
55–65 % coverage compared to a conventionally tilled soil without mulch
cover. This indicated reduced evaporation losses during summer months. A
similar result was reported by Sinkevičienė et al. (2009), while Raza et al. (2013) did not find significant mulch
related differences in near surface soil moisture. The data of Kálmar et al. (2013) on different degrees of
coverage clearly indicate that evaporation reduction requires a minimum
coverage of >50 %. Compared to other reports, this is still a comparatively
low percentage (e.g. Unger et al. 1991;
Mitchell et al. 2012).
Also under Mediterranean
conditions, surface coverage is an important water conservation practice.
Mrabet et al. (2003)
reported 10 % higher water storage over summer when soil was covered by a
mulch layer compared to no coverage. Lampurlanés and Cantero-Martínez (2006) demonstrated that higher
water content under no-tillage compared to conventional tillage in a Mediterranean
climate was attributed exclusively to the higher residue cover. Furthermore,
Verhulst et al. (2011),
comparing no-tillage and conventional tillage with and without residues in an
experiment in Mexican highlands, confirmed that higher soil water content was
generally found under residue covered treatments, particularly during dry
periods. According to Bennie et al. (2001),
evaporation reduction by residues is effective during the first 10 days
after surface wetting and requires a minimum of 80 % shading. The high
effect during the energy limited first stage of evaporation decreases during
the flux limited second stage and diffusion limited third stages of evaporation
(Steiner 1994).
Long-term moisture conservation during prolonged dry periods is less feasible
(Yunusa et al. 1994).
In a tropical residual moisture
regime, Zaongo et al. (1997)
reported a 28 % decrease in evaporation by mulch coverage. A similar value
was measured by Eberbach et al. (2011).
Ramakrishna et al. (2006)
found up to 22 % higher soil water content in a mulched soil profile. A
comprehensive modelling study of Jalota and Arora (2002) confirmed that mulching was
highly effective to reduce evaporation, which was the dominant water loss
component in the simulated dry tropical environment.
Concerning runoff losses, the
protective effect of surface residues is largely documented. Runoff decreases
exponentially with increasing surface cover. According to the USDA, minimum
tillage is defined as having a least 30 % ground cover and no-tillage 50 %
cover, respectively (Rust and Williams s.a.). Following the relation given
by Zuazo and Pleguezuelo (2008),
expected average runoff reduction would be 75 and 90 %, respectively. Klik
and Eitzinger (2010)
estimated a 36 % reduction in runoff losses by no-tillage compared to
conventional tillage for the erosion sensitive semi-arid hilly region of
Eastern Austria. At a Mediterranean site in South East Spain, Gómez et al. (2004) reported a 66 %
reduction of runoff by grass cover compared to a bare soil surface. Cogle et
al. (2002)
measured 64 % reduction in runoff by rice straw amendment compared to an
uncovered soil during a 5-year experiment in the semi-arid tropics in India.
Comparison between runoff reports, however, is difficult due to large
variability in experimental conditions.
The
overall hydrological role of mulching is resumed in Box 1. In spite of a
general positive hydrological impact of mulching in all water-limited
environments, implementation can conflict with other residue uses (particularly
animal feeding in the context of small-holder farmers; Erenstein 2002)
as well as phytosanitary considerations
Mulching and water management
Mulching is highly effective to prevent evaporation and
runoff, being the dominant loss components in most dryland ecosystems.
Concerning evaporation, surface covers provide an effective buffer for dry
spells during rainy periods with high evaporative demand (e.g. temperate
climate summer, tropical rainy season). The effect is highest after surface
wetting and decreases with time due to drying of the soil surface. A main
challenge is the relatively high residue cover required for an effective
control. Surface cover effects on runoff are high even at lower coverage. The
reduction in runoff is mainly a function of site specific vulnerability, which
is particularly high on steep slopes during concentrated rainy seasons in
semi-arid tropics and for plantations (e.g. olives, citrus, vineyards) with
large area of bare soil surface as frequently found in Mediterranean cropping
system
Stubble tillage
A common measure to reduce post-harvest evaporation losses is stubble
tillage. It is a measure applied during the fallow period between consecutive
crops, while surface cover by mulch can potentially protect the soil surface during
the whole year. As reported above, evaporation during prolonged dry periods is
low and also other losses (runoff, drainage) are negligible during dry seasons
in storage-driven and residual moisture ecosystems. Thus, stubble tillage for
water conservation is mainly effective in supply-driven summer–rainfall
agro-ecosystems. Several recent studies, however, questioned the water-saving
potential of stubble tillage (Pekrun et al. 2011; Kálmar
et al. 2013). Also
early studies from semi-arid summer rainfall sites in the US Great Plains,
resumed by Unger et al. (1991),
reported lower water storage during the fallow period, higher evaporation as
well as increased runoff from stubble tilled compared to residue covered soils.
Therefore, evidence is growing that stubble tillage as a traditional management
measure before summer fallow in semi-arid supply-driven ecosystems is
ineffective for soil water and rainfall conservation
Initial depletion
Bare soil fallowing is a traditional measure for soil
recovery. In water-limited ecosystems, it is mainly intended to replenish soil
water storage before the subsequent main crop. Depending on the extent of
drought and rainfall distribution, fallowing might extend from short duration
of unplanted soil between two consecutive crops to a whole non-cropped
vegetation period.
In supply-driven cropping systems, there was
traditionally a fallow period between harvest in early summer and the
subsequent crop seeded in late autumn or after winter. Although there were
early advocates of permanent plant cover, only recently cover crops have been
promoted as an alternative to bare soil fallowing. They avoid nutrient losses
and soil erosion, provide additional organic input to the soil and improve its
physical, chemical and biological quality. Introduction of an additional crop,
however, was considered to reduce water storage compared to an otherwise bare
soil, resulting in higher depletion at planting of the subsequent main crop. On
the contrary, Bodner et al. reported
only low differences in evapotranspiration between a cover cropped and a bare
soil under semi-arid, supply-driven conditions in East Austria. In a related
simulation study, Bodner et al. showed that there were hardly any differences
in spring profile water storage and no significant relation between cover crop
water consumption and yield of a subsequent maize crop. These different
findings are mainly related to the duration and climatic conditions during
cover crop growth. Those studies reporting significant soil water depletion
were conducted in locations with higher temperature during cover crop growth
and/or predominant winter rainfalls. On the contrary, in the semi-arid
continental climates of Central and Eastern Europe, the main growing period of
cover crops is autumn until crops are terminated by frost before winter. Due to
the low evaporative demand during their growing period, they show high
water-use efficiency and low water consumption. Thereafter, winter rainfall is
generally sufficient to refill water storage.
There are also reports of cover cropping during the rainy
season in dry Mediterranean and tropical climates where the yield risk of soil
water depletion is higher due to storage dependence of the subsequent crop. The
comprehensive study of Islam et al. showed a substantial reduction in soil
water recharge by winter rainfall with cover crops. In addition, Ward et al. (2012) found reduced soil water storage induced by a cover
crop. However, both studies indicated that early killing of cover crops reduced
their water consumption while maintaining hydrological advantages like reduced
evaporation, higher rainfall infiltration and lower runoff. In semi-arid
tropics where the rainy season is mostly used for cash crop growth, cover
cropping is hardly feasible. In more sub-humid conditions, however, legume
cover crops, often established within relay intercropping system, could offer
possibilities to alleviate N-fertilizer constraints and improve soil fertility.
Bayala et al. studied conservation agriculture in semi-arid tropics and showed
that cover crops were found at sites with rainfall higher than 600 mm,
while positive yield effects were reported when rainfall exceeded 800 mm.
In dry Mediterranean regions, traditional farming systems were often
based on biennial crop rotations including a fallow year between main crops
(Ryan 2011). Due to
increasing land pressure, fallows have decreased and extensive studies have
been conducted for improved rotations including feed legumes. Comparing barley
following fallow or legumes such as vetch and lathyrus as well as barley
mono-cropping, Jones and Sigh (2000) showed
highest overall growth potential in the barley–legume systems. Pala et al. (2007) compared several improved biennial rotations with wheat
as main crop in terms of yield and water-use efficiency. Highest availability
of stored soil moisture after fallow resulted in best wheat yields. Still, also
vetch and lentil conserved sufficient water for relatively high wheat yield and
resulted in highest water-use efficiency on a system basis. Inefficient
rainfall storage during fallowing, due to high evaporation losses and weed
growth, has therefore led to improved crop rotations in several Mediterranean
cropping regions (Farahani et al. 1998).
In semi-arid tropical and subtropical regions, the main cropping season
largely coincides with the rainy season. Still. some crops, e.g. chickpea,
wheat, pearl millet, mustard, are also grown in the post-rainy season relaying
most exclusively on residual soil moisture (Serraj et al. 2003). Rao et al. (2011) provided
evidence that cropping system intensification from a single crop following
fallow to double cropping is feasible on soils with high storage capacity in
semi-arid tropics by better timing of rainy- and post-rainy-season crops.
Water-saving practices such as mulching in the rainy season crop improves water
storage for the subsequent dry-season crop. Intensification increases water-use
efficiency by better using stored soil water and substantially reducing runoff
and evaporation losses during the early rainy season
Crop rotation: water storage vs. water depletion
Traditional
cropping systems in dry environments frequently include prolonged periods of
uncovered soil to enhance water storage. In all hydrological situations, higher
productivity and more efficient soil water use beyond traditional cropping
systems is feasible. Prolonged bare soil increases unproductive water losses,
which otherwise could be redistributed to transpiration in an intensified crop
rotation. However, increasing overall system biomass productivity still could
imply lower yield of the main cash crop. This is most evident when substituting
a fallow year by a biennial rotation under dry Mediterranean conditions. On the
contrary, cover crops in temperate supply-driven environments are of low risk
for depleting water storage due to low evaporative demand during their autumn
growing season. In tropical/subtropical residual moisture environments, the
amount of water conserved in soil between rainy- and dry-season crops is limited.
Still, enhanced higher water-use efficiency of rainy season crops and timely
sowing can optimise the availability of stored moisture to dry season crops
Long-term measures
Long-term soil management measures focus on improvement
of soil water storage capacity. Storage capacity is strongly influenced by
texture and profile depth, which are natural site constraints. However, two
important soil properties related to water storage are essentially influenced
by plant–soil interactions in the cropping system, i.e. soil structure and soil
organic matter. Tillage and management of organic matter are key areas of
agricultural practices, which both essentially condition soil hydraulic
properties
Tillage systems
There is an extensive literature on tillage influences on
soil hydraulic properties. Comprehensive reviews have been presented.
Concerning soil properties, different intensity of mechanical disturbance
changes the soil pore size distribution and pore geometry.
Several long-term tillage experiments have been conducted
under temperate climate conditions. Azooz et al. reported higher storage pores
<7.5 mm diameter in no-tillage compared to conventional tillage, while
the volume of pores >150 mm diameter decreased. These differences were
stronger in a sandy loam compared to a silty loam soil. Kay and VandenBygaart (2002) reviewed results from tillage experiments in Canada and
confirmed the general trend of decreasing macropore and increasing storage pore
volume in conservation tillage systems. Tebrügge and Düring (1999; Germany) found smaller total porosity and macropore
volume in a long-term no-tillage systems on a silty clay loam soil, while pores
<10 mm were slightly higher under no tillage. Differences in total
porosity and macroporosity were highly transient and reduced significantly
after winter. Lipiec et al. (2006; Poland)
found a more distinct peak in a bimodal pore size distribution of a silt loam
soil at 1 mm pore radius for no-tillage, while the peak at 110 mm was
more pronounced in the conventional tillage treatment. The higher macroporosity
of conventional tillage increased the steady state infiltration rates.
There seem to be no substantial differences in tillage induced pore
trends in other climates. Pagliai et al. (1995) analysed
pore size distribution and pore geometry under different tillage systems in a
silt loam and clay soil in Italy. Treatment differences were higher in the silt
loam soil compared to the clay soil with higher storage pore and reduced
macropore volume in no tillage. Macropore geometry in conventional tillage
showed lower pore connectivity compared to no-tillage systems where macropores
were predominantly of biological origin. Bescansa et al. (2006) and Fernández-Ugalde et al. (2009) reported the same trend for a clay loam and a silt loam
soil, respectively, in a semi-arid climate in Spain, leading to better crop
performance in the reduced tillage systems during dry years. South America is
among the leading continents in reduced tillage (Derpsch 1998). Ferreras et al. (2000) and Sasal
et al. (2006) found higher volume of larger pores in a loam and silt
loam soils in the Argentina pampas under conventional tillage, while fine pores
<20 mm were slightly higher in the no-tillage system. Sasal et al. (2006) confirmed the different pore geometry of macropores
between tillage systems, underlining the important role of biopores in no
tillage.
Under tropical conditions, Osunbitan et al. (2005) reported lower total porosity and macropore volume
under reduced tillage in a loamy sand in southwestern Nigeria. Water retention
was higher in the no-tillage system at lower pressure heads (<
−500 hPa). In spite of lower macroporosity, no tillage had highest
saturated hydraulic conductivity. This reveals the importance of continuous
large biopores that might have been higher in no tillage. Also in the study of
Bhattacharyya et al. (2006) in a
sandy clay loam soil in India, pore volume <7.5 μm was increased in no
tillage, while pores >150 μm in diameter had higher volume in the
conventional tillage system. Also in their study, no tillage had significantly
higher saturated hydraulic conductivity. Kumar et al. (2012) reported that long-term no tillage not only increased
the proportion of micropores (<10 μm) but also of large macropores
(>1000 μm), which decisively influence saturated hydraulic
conductivity.
While similar pore size
distribution trends are found in most tillage trials, for saturated hydraulic
conductivity some studies reported decreasing values with reduced tillage
intensity, while others reported higher saturated conductivity. This is
explained by the high spatial variability of large continuous macropores. In no
tillage, these pores are biologically formed structures such as root channels
and earthworm casts (Wuest 2001; Palm et al. 2010; Pagenkemper et
al. 2013; Bodner et al. 2014). We assume that the number of biopores is not always sufficient to
counterbalance the overall lower macropore volume in no-tillage soils. Some
studies reported the reduction of differences between tillage treatments with
time after soil disturbance. Particularly for tillage experiments, it is of
high importance to assess temporal dynamics of the system to capture the
overall management impact (e.g. Mappa et al. 1986; Kay 1990; Tebrügge and
Düring 1999; Schwen et al. 2011).
Tillage system effects on soil hydraulic
properties
There is a general trend of reduced
tillage to increase water storage by higher volume of fine storage pores, while
total porosity and macropore volume are reduced. This trend is similar in all
hydrological regimes and for variable soil textures. Tillage effects change
over time, particularly in the macropore range. Macropore-dependent hydraulic
properties such as saturated hydraulic conductivity, therefore, do not show a
unique trend in tillage experiments. Differences between tillage systems thus
cannot be fully captured without taking into account temporal variability.
Organic matter input
The key influence of vegetation on soil hydraulic properties is largely
recognised. It is a result of the soil structure–organic matter interaction. In
spite of this, targeted plant based management of soil hydrology is still at
its infancy. This is mainly due to the complex and dynamic, biologically
mediated processes driving the feedback between plant and soil (Angers and
Caron 1998). There
are two main approaches to manage soil hydraulic properties: The first is
organic fertilization using, e.g. crop residues, green manure, slurry and
farmyard manure. The second is crop rotation. A special case of the latter is
“biodrilling” as targeted soil priming by plant roots (Cresswell and
Kirkegaard 1995).
Haynes and Naidu (1998) give an
overview of soil physical effects of organic manure addition. Higher total
porosity and soil water retention over a wide range of pressure heads indicate
that enhanced soil structuring upon organic fertilization resulted in both
higher inter-aggregate macroporosity as well as higher volume of
intra-aggregate storage pores. At low pressure heads around PWP, the increased
specific surface area of soil amended with organic matter retains more water in
the soil. As a consequence, hydraulic properties and processes such as air
filled porosity and infiltration are improved. Organic input underlies
decomposition. Temporal changes of soil aggregation are therefore linked to the
turnover of organic carbon (De Gryze et al. 2006). Recent
studies, however, indicated that not the chemical recalcitrance of organic
residues per se, but the interaction between soil mineral particles and organic
matter itself (i.e. aggregation) largely determines the mean residence time of
organic substances in the soil (Schmidt et al. 2011). This is in agreement with Rawls et al. (2004) who showed that organic matter effects on soil
hydraulic properties decrease with increasing initial carbon content of the
soil. This fact points to the saturation of mineral surfaces, which cannot bind
to further organic substances, and therefore also the hydraulically relevant
process of aggregation is at steady-state equilibrium. This saturation process,
however, seems most relevant for organo-mineral complexes at the microaggregate
level. Evaluation of long-term fertilization trials by Blair et al. (2006a,b) showed
that the increase in aggregate mean weight diameter, i.e. a higher amount of
large aggregates, and related unsaturated hydraulic conductivity were most
strongly influenced by the labile fraction of organic carbon. The central
functional role of labile organic carbon would also explain that reduction in
total organic carbon concentrations in temperate soil often did not have marked
effects on soil properties (Loveland and Webb 2003), while on the contrary, substantial changes are
frequently reported from fertilization trials. Stabilisation of these easily
decomposable substances is linked to their physical protection from microbial
degradation within aggregates as stated by the porosity exclusion principle
(Dexter 1988), which in
turn explains their sensitive response to management such as tillage induced
turnover upon mechanical aggregate disruption.
For temperate climates, Miller et al. (2002) found
significantly higher water retention and hydraulic conductivity in a clay loam soil
with 17 g kg−1 total organic carbon (TOC) in a
semi-arid continental climate of the Canadian Great Plains due to addition of
cattle manure. Also in the above-cited studies of Blair et al. (2006a,b) with
20 g kg−1 TOC at the German site and
14 g kg−1 at the English site, organic fertilizer
input improved hydraulic properties via better soil aggregation.
Experiments conducted in Mediterranean climates also found a significant
improvement of soil hydraulic properties by organic matter amendment. Pagliai
et al. (2004) reported a strong increase in macropores
>500 μm with more elongated continuous pore channels by addition of
manure and compost on a silt loam Haplic Calcisol with 12 g kg−1 TOC.
The effect was most evident upon mineralisation of the organic amendments,
indicating the interaction with an enhanced soil biological activity. Shirani
et al. (2002) showed a strong increase in soil organic matter on an
arid silty clay loam with 5 g kg−1 TOC in Iran by
addition of farmyard manure, resulting in improved aggregation, lower bulk
density, higher saturated hydraulic conductivity and nearly double dry matter
yield of irrigated corn.
Benbi et al. (1998) and
Bhattacharyya et al. (2007) studied
change in soil physical properties due to organic matter addition under dry
tropical conditions in India. In both cases, farmyard manure addition to soils
with loamy sand and silty clay loam texture and low initial organic carbon of 2
and 7 g kg−1 TOC, respectively, enhanced aggregation,
resulting in higher saturated hydraulic conductivity.
Soils in dry climates have frequently low organic matter content. Thus,
addition of organic matter responds to a limiting property of these soils and
can be expected to substantially improve soil physical quality. The change of
hydraulic properties goes along with improved soil aggregation. Labile and
particulate organic carbon fractions are responsive to management such as
organic fertilization and tillage, enhance soil microbial activity and
influence directly and indirectly aggregation (Bronick and Lal 2005).
There are several studies on the effect of crop rotation on soil
hydraulic properties, although the direct effect of crops has been studied in
less detail compared to the effects of tillage and fertilization. The important
influence of crops on soil hydraulic properties is most clearly revealed when
comparison relates to land use change. Generally, soil structure is more
developed and more stable in forest and grassland soils compared to cropland,
resulting in higher total porosity, water retention and infiltration (e.g.
Francis and Kemp 1990;
Schwärzel et al. 2011; Kodešová
et al. 2011;
Gajić 2013). This is
mainly due to the higher organic carbon in forest and grassland soils. Plant
roots are a key factor influencing soil hydraulic properties in different crop
sequences. Their qualitative role for soil structure and hydrology is well
known from the hierarchical models of aggregation and porosity (Tisdall and
Oades 1982; Elliott
and Coleman 1988) as well
as from field soil surveys showing a crumby, loose and macroporous structure in
densely rooted soils (e.g. Rampazzo and Mentler 2001). Our focus here is on cropland. We will first address
the role of crop rotation in general; then, we specifically discuss the concept
of root induced biodrilling.
For crop rotation experiments in temperate climates, Dexter et al. (2001) found higher water retention and hydraulic conductivity
in a loamy sand soil in Poland when including a cover crop such as mustard or
clover/grass mixtures in the crop rotation. Carof et al. (2007) showed that under no-tillage cover crops enhanced pore
continuity in a silt loam in northern France, while Bodner et al. (2008) found that cover crops stabilised effective pore
properties over winter on a silt loam soil in semi-arid Eastern Austria.
Villamil et al. (2006) studied
the effect of inclusion of rye, vetch and vetch/rye mixture as cover crops in a
corn–soybean no-tillage rotation on a silt loam soil in Illinois, USA, with a
continental summer rainfall climate. Cover crops increased organic carbon,
aggregate stability and water holding capacity, while reducing bulk density and
penetration resistance. Głąb et al. (2013) compared
long-term effects of different crop rotations, i.e. sugar beet–spring
triticale–faba bean–winter triticale; spring triticale–winter triticale–oat;
winter triticale–spring triticale, on soil hydraulic properties for a loam soil
in southern Poland. They found significant change in water retention properties
by crops, with triticale enhancing plant available water. However, the crop
effect was not stable over time and no long-term crop rotation effects could be
demonstrated. McVay et al. (2006) reported
effects of tillage and crop rotation from five trials in a continental climate
in Kansas, USA, all having silt loam soils. Changes were found only in the
upper soil layer from 0 to 5 cm. Crop rotations with cereals increased
soil organic carbon, but compared to tillage intensity did not have a
significant effect on water holding capacity.
Blair et al. (2006c)
evaluated a long-term crop rotation experiment on two clay-rich Vertisols under
semi-arid conditions in Australia. More frequent inclusion of forage legumes (Medicago sativa L.)
in the rotation enhanced aggregate mean weight diameter and hydraulic conductivity
due to higher soil organic carbon. In addition, Armstrong et al. (1999) found higher hydraulic conductivity and enhanced
macroporosity in a clay soil in Australia under legumes compared to sorghum.
Miglierina et al. (2000) reported
enhanced water holding capacity from a long-term rotation trial on a sandy loam
in semi-arid Argentina when including a vetch as legume component in a
wheat-based cropping system. Masri and Ryan (2006) found
higher organic matter, aggregation stability and infiltration due to legumes
such as M.
sativa L. and V.
faba L. in a durum wheat based cropping system compared to
traditional wheat–fallow and continuous wheat rotations on a clay soil in Syria
with a dry Mediterranean climate.
Also under tropical conditions, improved water retention and
transmission properties in legume-based rotations were reported by
Bhattacharyya et al. (2006). Effects
in the sandy clay loam site, however, were mainly evident in the no-tillage
system. Chenkual and Acharya (1990) compared
rice–wheat and maize–wheat rotations on a silt clay soil in India. Maize
enhanced hydraulic conductivity and profile water storage compared to rice,
which they related to different soil drying.
We notice here that, in a meta-study of Hathaway-Jenkins et al. (2011), no differences were found between conventional and
organic farming systems. Similar to other management measures, also crop
rotation studies reveal the importance of the time scale of changes (Głąb et
al. 2013). A
transient crop impact can be overlaid by several environmental factors such as
wet–dry and freeze–thaw cycles or raindrop impact that commonly shape soil
hydraulic properties (Logsdon et al. 1993; Bodner
et al. 2013).
A main causal factor for the observed changes in hydraulic properties
reported by several crop rotation studies were changes in soil organic carbon.
Much less attention was put on the direct role of plant root traits for
hydraulic properties. Still, there is an increasing interest on capturing the
impact of different root systems on soil physical properties to eventually
allow their targeted management. In more recent times, this work was pioneered
by Cresswell and Kirkegaard (1995) who
established the concept of primer plants to biologically improve soil porosity
for subsequent plant growth. Although their early experiments with canola for
biodrilling hardened subsoil in Australian did not show significant impact,
several follow-up studies have been done, which were resumed by Yunusa and
Newton (2003). Generally, we can identify two targets of root-induced
soil priming: Remediation of natural or management induced physical constraints
such as subsoil compaction, and improvement of soil structure related pore
properties with relevance for cropping systems, i.e. water transmission and storage
pores.
Stirzaker et al. (1996) reported
improved barley root penetration through a compacted soil layer via biopore
channels created weather artificially or by ryegrass and lucerne. Nuttall et
al. (2008) considered that primer plants with a highly branched
root systems, e.g. Lotus
corniculatus L. or Hedysarum
coronarium L., leave a biopore mosaic that allows better
subsoil water extraction of a subsequent wheat crop compared to a less branched
and coarser biopore geometry after lucerne. Williams and Weil (2004) showed the positive effect of radish cover crop roots
penetrating a compacted layer and creating growth paths for a subsequent
soybean. Among different cover crops, radish had higher potential to penetrate
through dense compacted layers compared to rapeseed and rye (Chen and
Weil 2010). Perkons
et al. (2014) measured higher root length density of main crops such
as wheat, barley and rapeseed in deep soil following a taproot species compared
to a fibrous rooted pre-crop and related this to enhanced large-sized biopores.
Stirzaker et al. (1996)
mentioned the problem of root–soil contact for roots growing in large biopores.
White and Kirkegaard (2010) studied
this problem in detail, showing that wheat roots growing in biopores interacted
with surrounding soil by root hairs, while roots growing in cracks had reduced
root hair formation. Athmann et al. (2013) showed
that plants growing in biopores establish contact to soil either by growing
along the pore wall (barley) or via lateral roots (rapeseed). The capacity of
primer plants to alleviate soil compaction depends strongly on the degree of
compaction. In case of intermediate compaction levels, tap-rooted crops with
strong root mechanical resistance against buckling (Clark and Barraclough 1999) and perennial forage legumes (Lesturgez et al. 2004) can be sufficiently effective. In case of strong
compaction or naturally hardset horizons, woody species (Yunusa et al. 2002; Bartens et al. 2008) would be
required to effectively improve penetrability of these layer for subsequent
crops.
Beyond biopore creation in
dense layers, roots can be targeted as a natural management tool for soil
structural porosity to enhance water holding capacity as well as saturated
hydraulic conductivity. Although there is an increasing knowledge on root–soil
structure interactions (cf. Section 2.4), which has substantially advanced due to modern
3D-imaging methods, there is still a significant gap between process analysis
at the single root scale and upscaling to the cropping system. Some findings in
crop rotation studies (e.g. Dexter et al. 2001), however, clearly suggest
that roots are directly involved in the improvement of hydraulic behaviour at
the field scale. Rasse et al. (2000) showed the higher macroporosity and saturated hydraulic conductivity
as a result of alfalfa root penetration and enhanced wet–dry cycles in the
rhizosphere. Bodner et al. (2014) provided evidence for the impact of cover crop roots on the soil pore
size distribution. They revealed that root growth influenced different pore
size classes and that root systems dominated by coarse, e.g. legume, and fine,
e.g. brassica, root axes had distinct impact on hydraulic properties. The
authors suggested mechanisms at the root–soil interface underlying their macroscopic
observations. There is still need for further field scale studies that provide
quantitative relations between root traits, soil structure and hydraulic
properties and their effects on a subsequent crop.
Organic
matter and plant roots: biological effects on soil hydrology
Organic fertilization and crop species influence soil
hydrology. Although these effects are weaker compared to tillage, clear crop
effects are found for lighter soils and by inclusion of legumes in the crop
rotation. Crop effects are strongest in no-tillage systems, while soil
mechanical disturbance overlays the crop influence on hydraulic properties.
Organic substances themselves influence water storage. Their main function is
via soil structure and structural porosity. Crop rotation effects, e.g. cover crops
vs. fallow, are often related to different levels of organic matter input. In
addition differences in root system properties and their turnover dynamics are
relevant factors for hydraulic properties, pore stabilisation and improved
subsoil exploration by subsequent crop
Plant-related measures
Roughly, we can distinguish between crop stand management and measures
related to breeding. Stand management provides short term adaptation by
optimising seeding date and stand density. Besides classical field experiments,
today SPAC models provide efficient tools for in silico experiments to optimise
site specific cropping system design and adaptation (e.g. Messina et al. 2006; Chenu et al. 2011; Jeuffroy
et al. 2014).
Breeding is an immediate option when referring to the choice among existing
cultivars differing in drought resistance. A long-term adaptation could be
expected from on-going breeding research. This distinction is certainly
somewhat arbitrary as also existing cultivars are a result of previous research
and breeding work. Therefore, we distinguish between morphological adaptation,
e.g. via plant height and harvest index, and phenological adaptation, e.g. via
earliness, as the predominant selection strategy of past breeding efforts, on
the one hand, and change of secondary physiological traits, on the other hand,
that is still largely at the stage of research.
Short term measures
Early
sowing
Under dry
conditions, optimisation of seeding time is a key measure to match plant demand
with water availability. This measure interacts with earliness as breeding
trait to escape dry periods. Here, we will just refer to the hydrological
impact of changed seeding time, while other related issues, e.g. phytosanitary
aspects or frost damage risk, are not discussed. There can be three main
reasons for early sowing in dry environments: (i) seasonal variation in
evaporative demand improves water-use efficiency of early (winter) sown
crops/cultivars because part of their growth takes place under lower water
potential gradients to the atmosphere (cf. ET 0 in Eq. 6; e.g. Brown et al. 1989); (ii) early seeding shifts
sensitive stages such as flowering and grain filling to periods of better water
availability (e.g. Herrero and Johnson 1981); and (iii) deeper rooting of
early sown crops improves avoidance of early droughts (Barraclough and
Leigh 1984;
Brown et al. 1989;
Incerti and O’Leary 1990).
Ehlers and Goss (2003) reported higher yield of
early sown winter wheat and winter barley on a light soil in the continental
semi-arid climate of Eastern Germany. Particularly on drought prone low storage
soils, earlier sowing results in better water availability at flowering and
grain filling (Boese 2010).
Schwarte et al. (2006)
showed an optimum curve for seeding date of triticale in continental semi-arid
Iowa, USA, requiring 533 °C days before winter to obtain highest yield
potential. Kirkland and Johnson (2000)
tested alternative seeding dates, i.e. fall and April, compared to traditional
May sowing for rapeseed at a continental site of the Canadian prairie where hot
dry weather frequently affects flowering. The earlier sowing date provided on
average 38 % yield advantage due to better flowering and grain filling.
Berzsenyi and Lap (2005)
and Berzsenyi and Dang (2008)
studied the effect of sowing date on maize yield in the semi-arid temperate
climate of Eastern Hungary. Early sowing reduced yield stability, while late
sowing resulted in lower yield potential. In years with favourable spring
conditions, early sowing produced highest yields. Generally, a trend towards
earlier sowing can be expected considering long-term climatic shifts.
reviewed measures
for sustainable crop production under drought in Mediterranean climates. He
attributed half of yield improvement over the last decades to agronomic
measures, mainly advanced sowing time and fertilization both leading to higher
early vigour and better match of water availability with crop demand. Eastham
et al. (1999)
showed that early sowing of wheat and lupine significantly enhanced overall
water use and reduced the energy-depended first stage soil evaporation due to
better soil coverage. Mahdi et al. (1998)
determined a yield loss of 5 % per week for durum wheat when sowing was
delayed after first of November in Syria. However, sowing too early resulted in
suboptimum stand establishment due to the lack of moisture for homogeneous
germination and emergence. In addition, Latiri et al. (2010) reported better wheat yield
in Tunisia with early sowing for years with no stress at germination.
Gomez-Macpherson and Richards (1995)
investigated yield effects of sowing date at three Australian sites. Early
sowing increased biomass but not yield, suggesting that there was higher
competition for assimilates between vegetative and generative sinks.
Particularly under dry conditions, grain yield is often sink limited (Duggan et
al. 2000;
del Moral et al. 2003)
and depends strongly on a high number of kernels per spike and kernel weight
per spike (Denčić et al. 2000).
Higher vegetative biomass may impair the optimum formation of these yield
components in summer–dry climates. For faba bean under dry Mediterranean
conditions of Australia, Loss et al. (1997)
on the contrary showed that early sowing improved water use during grain
filling. Early sown plants escaped drought and increased number of pods per
square metre and seed weight.
Under dry tropical and subtropical conditions, it
is particularly important to match water availability with crop demand to
complete most phenological stages before onset of the dry season. Both field
experiments and modelling studies showed that rainfed rice production is mostly
influenced by drought escape via appropriate seeding date and/or earliness of
cultivars. Sial et al. compared yield components and yield of wheat mutant
lines in response to seeding time in Pakistan. A shorter and more stress prone
grain filling period decreased yield around 50 % for later sowing dates.
Dzotsi et al. used a simulation model to study optimum sowing date of maize in
Southern Togo during the main and secondary rainy season. In both cases, early
sowing improved yield. Additionally, very early cultivars were required during
the shorter secondary rainy season.
Early sowing: synchronisation of supply and demand
Optimisation
of sowing date is a main requirement for crop management in dry regions.
Changes in traditional sowing dates often came along with changes in crop
rotations and new cultivars. Early sowing dates are most important in climates
with a distinct dry season to escape terminal drought, while they are less
effective in case of intermittent drought. Under temperate continental
climates, sowing date has a rather broad optimum, while drastic yield effects
are reported from climates with distinct dry season. Increasing yield by early
sowing requires appropriate conditions for optimum stand establishment and
early vigour. Other management measures like deeper sowing and seed priming may
be required in case of risk for dry conditions at early sowing dates.
Reduced stand density
Reducing stand density aims to a reduction of
intra-specific competition and enhanced water availability to the single plant.
Particularly, water availability for the post-flowering period should be
improved to optimise yield formation under conditions of limited in-season
rainfall. While early sowing is an agronomic measure of drought escape, reduced
stand density is related to water saving. The main disadvantage related to
lower stand density is an increase in evaporation losses and possibly also
higher runoff, particularly for wide-row crops. The effect on yield is complex
and involves modified radiation use, changes in source-sink relations and
assimilate translocation. Particularly, cereals have high plasticity in yield
formation with mutual compensation between yield components. Ehlers and Goss (2003) still noted a rule that generally applies: the drier
the situation, the lower the optimum stand density. Beside lower stand density,
i.e. less plants per square metre, also changes in plant spacing for a given
density is discussed here as it also aims to reduce intra-plant competition.
For the semi-arid region of Eastern Germany with frequent
moisture deficit during grain filling, Waloszczyk (1991) reported higher yield stability for lower stand density
of winter wheat with 300 plants m−2at a relatively high average
yield level of 8.1 Mg ha−1. This was mainly due to higher
harvest index and probably depletion of moisture by more straw biomass in
denser stands. Under dry continental conditions in Montana, USA, at an average
yield level of 3.3 Mg ha−1, Chen et al. found an optimum
seeding density of spring wheat at 215 seeds m−2 with highest
kernel weight and high number of kernels per spike. Particularly, under drier
conditions, higher seeding rates resulted in the loss of all secondary tillers.
McKenzie et al. investigated different seeding rates of spring barley under
semi-arid continental conditions of Southern Alberta, Canada. Yield with an
average level of 4.4 Mg ha−1 slightly increased with
higher seeding rate from 150 to 350 seeds m−2, while kernel weight
and protein content decreased. In a similar climate in Saskatchewan, Tompkins
et al. found that narrow row spacing and
higher seeding density improved yield, pre-anthesis water use and overall
water-use efficiency. For row crops, Sárvári found that optimum plant density
of maize in semi-arid Eastern Hungary was strongly dependent on the cultivar
and varied between 6.5 and 9.0 plants m−2. Above optimum densities
reduced yield and yield stability. For sugar beet, Ehlers and Goss reported
that seeding densities in semi-arid and humid regions of Germany were similar.
They explained this by reduced leaf re-growth during the later season due to
water shortage thereby reducing assimilate competition between leaf and beet.
For a summer–dry climate of Inland Pacific Northwest,
USA, Schillinger found no differences in
yield of spring wheat, barley and oat due to varied seeding rate at an average
yield level of 2 Mg ha−1. Arduini et al. (2006) found highest yield in durum wheat at highest density
with levels of 200, 250, and 400 seeds m−2 in Italy at a yield
level of about 6 Mg ha−1. Higher seeding density increased
post-heading assimilate translocation from vegetative parts to grain. When
increasing seeding density from 225 to 340 seeds m−2, Fang et al. (2010) measured increased grain yield of winter wheat in a
terminal drought environment in China during wetter years with average yield
level of 6 Mg ha−1, while in drier years with average
yield level of 3.5 Mg ha−1, the contrary trend was
observed. Soil water content was lower under high seeding density and
post-heading dry matter accumulation and assimilate translocation increased.
Kleemann and Gill investigated the effect of increased row spacing of spring
wheat in Australia from 18 to 54 cm in order to conserve soil moisture for
grain filling. However, they did not find higher post-flowering water use for
larger row spacing to avoid significant yield decrease from 2.9 to
2.3 Mg ha−1 due to reduced radiation interception.
Overall, WUE was lower in treatments with wider row spacing. Barbieri et al.
found a higher yield of maize when reducing row spacing from 70 to 35 cm.
Narrower rows increased early season evapotranspiration and overall water-use
efficiency. Similar results were reported by Sharratt and McWilliams from
Michigan, USA, who also found more even root distribution and significantly
higher radiation interception of narrow spaced maize. Also for faba bean, Silim
and Saxena (1993) reported
improved radiation and water use, higher dry matter and yield leading to
overall higher water-use efficiency with narrow row spacing and higher seeding
rate in a dry Mediterranean climate in Syria.
Simmonds and Williams observed that higher seeding density in
groundnut in India slightly decreased evaporation, while increasing
transpiration mainly during the vegetative stage. Dense stands enhanced water
extraction from deep soil layers. Buah and Mwinkaara compared the yield at different
densities of sorghum in the Guinea Savanna zone at average yield levels of
2 Mg ha−1. There was no significant yield difference
between densities of 5 and 13 plants m−2. Huda (1988) on the contrary
reported a higher sorghum yield when increasing plant density from 2 to 16
plants m−2 in India. Pearl millet is a frequently cropped
tillering tall cereal under dry tropical conditions. Generally, it is planted
at low density to reduce the risk of crop failure via staggered development of
main stem and tiller panicles. De Rouw (2004), however, showed that an
intermediate plant density of 1 hill m−2with three plants per hill
increased the frequency of higher yields in the Sahel.
Stand density and water saving
Yield is
most responsive to lower stand density when water saving for improved grain
filling is effectively obtained. Therefore, yield effects are strongly
dependent on site conditions. At lower stress levels in temperate and some
Mediterranean sites, higher densities often provide a yield advantage,
particularly for crops that cannot compensate low seeding density via increased
fertile tillers or branches when water supply is sufficient. At sites with
intense water stress and very low yield level, similar yields are obtained over
a range of seeding densities, indicating that changes in inter-plant
competition do not determine significantly yield. It appears that under
intermediate terminal stress levels, water saving by lower stand density is
most effective to optimise yield. The increase in soil evaporation by lower
density and/or wider row spacing depends on rainfall frequency and is higher
for an intermittent drought pattern compared to a prolonged dry period. Beside
evaporation, reduced radiation interception by sparse stands might limit growth
and increase weed competition with crop plants
Breeding in the past—phenology and
partitioning
Breeding has contributed to increase yields in dry regions with an
average of 0.2 % per year. However, progress was less compared to high
yielding environments with 2.9 % per year (Trethowan et al. 2002). Reynolds et al. estimated that a 2 % yield
increase per year of wheat is required to meet rising global food demand.
For small grain cereals, Slafer and Araus pointed to semi-dwarfism as a
major change in cereals that led to improved yield in stressful environments.
They considered that breeding has led to an optimum stature of cultivars, and
therefore, selection for plant height provides few possibilities for future
improvement. Further reduction of plant height on the contrary would lead to
poor radiation use efficiency. The contribution of harvest index to yield
improvement was documented in several retrospective studies. Shearman et al. (2005) found a linear correlation of yield and harvest index
for wheat in the UK until 1983. Thereafter, yield increase was related with
higher pre-anthesis growth rate and soluble carbohydrates in the stem together
with higher grain number per square meter, i.e. higher sink strength. Aisawi
found harvest index to explain yield increase of 0.59 % per year in a
CIMMYT germplasm collection between 1966 and 1990. Thereafter, increase was
associated with the length of grain filling period. A similar result was found
by Sadras and Lawson for Australia. Harvest index increased linearly for
cultivars released between 1958 and 2007. Yield gains after the 1980s were
associated with higher crop growth rate due to better radiation use efficiency,
possibly related to increased stomata conductance and/or greener leaves.
Furthermore, enhanced carbon translocation has substantially contributed to
better grain filling. Araus et al. resumed from retrospective studies that there
was low change in total biomass, while mainly optimisation of partitioning
assimilates provided steady yield increase in small grain cereals. For
Mediterranean environments, Álvaro et al. and Isidro et al. also found a
breeding trend to earlier heading in Spanish and Italian durum wheat cultivars.
Maize also had higher historical yield increase in well
watered compared to stress environments. Under stress, yield gains were mainly
associated to shortening of the anthesis-silking interval (ASI) and longer
green leaf area duration, commonly known as “stay green”. In a retrospective
study on temperate maize cultivars released in Canada between 1950 and 1980,
Tollenaar and Wu (1999) found
enhanced resource capture under stress by higher leaf longevity, more active
roots and better assimilate translocation to grains. Tollenaar and Lee (2002), therefore, concluded that main yield gains in maize
were not due to higher yield potential or heterosis per se, but were mainly
based on better stress tolerance. Campos et al. (2006) tested
traits related to yield progress in the US Corn Belt for Pioneer cultivars
released between 1953 and 2001 and found shorter ASI to best explain better
performance under water stress. Tokatlidis and Koutroubas (2004) showed that better stress resistance in modern
cultivars is related to the high planting densities required for high yields.
In a US study, also Duvick (2005) revealed
that yield potential per plant has not increased between 1934 and 2004. Newer
hybrids yielded more than older ones because of higher ability to withstand the
stress associated with higher plant density. Using a model to explain historic
yield trends in US maize, Hammer et al. found changes in root architecture
associated with higher water uptake to be the main reason for better abiotic
stress resistance. For tropical maize, Bolaños and Edmeades found ASI to be the most relevant breeding
trait for better drought resistance. Furthermore Monneveux et al., testing two
CIMMYT populations, confirmed that ASI and generally improved partitioning of
assimilates to the ear after flowering had highest impact for better yield
under tropical dry conditions.
For
tropical and subtropical dry regions, sorghum and pearl millet are important
crops aligned to longer breeding programs. As average yield level in Africa and
Asia is still low (600–900 kg ha−1), breeding as well as
improved management provide huge potential for yield increase. Furthermore,
there is high diversity of available germplasm. Yield potential has
substantially increased with the introduction of hybrids. Yadav et al. mentioned
higher harvest index and earliness as key traits for improved drought
resistance of pearl millet cultivars from routine breeding programs, while for
sorghum, in addition to earliness, also stay green types have contributed to
better yield in dry environments
Crop improvement for drought resistance
at a crossroad?
Crop
improvement has achieved substantial yield advances of existing cultivars for
dry environments, although to a lower extent than for non-stress environments.
Species with long tradition in breeding like small grain cereals have been
optimised over several decades. Substantial yield gain has resulted from
improved stature, i.e. mainly harvest index, and adaptation of phenology to
escape post-flowering drought. However, breeding progress from selection for
these traditional traits has slowed down. In maize, successful selection traits
were shorter ASI and stay green, with improved rooting leading to better
drought avoidance. Crops with more recent breeding history and low yields in
dry regions such as pearl millet and sorghum still offer potential for
improvement based on traditional morphological and phenological adaptation. The
necessity of new approaches for crops with long breeding history, better
knowledge of drought resistance mechanisms and new screening tools increasingly
popularise integration of secondary traits in breeding research.
Breeding
for the future—long-term measures
Long-term measures
at the plant level strive to overcome current physiological limitations to
growth and yield production under drought. Introduction of C4photosynthesis
into C3 plants is still an ultimate aim among some plant
physiologists. However, there seem to be several opportunities for improved
growth under water shortage that are more likely to disseminate from research
to practical breeding. Cattivelli et al. considered three approaches as
decisive for future breeding: physiology, molecular genetics and molecular
biology. For crop ecology, the focus is on exploiting biodiversity in
physiological traits at the plant level, which are involved in regulating water
flow through the SPAC. We will give some examples how physiological mechanisms
of stress resistance that were introduced in Section 2.2 have been used in a
breeding context. The integration of physiological traits into breeding is
mainly dependent on efficient screening methods. There is an increasing number
of promising tools that could facilitate crop improvement via better
physiological characterisation (e.g. Nakhforoosh et al. 2013).
3.6.5 Breeding
for dehydration avoidance
Dehydration avoidance can be
achieved by water saving and water spending. Water saving due to higher intrinsic
water-use efficiency has been popularised in breeding research with the
introduction of carbon isotope discrimination (CID) as an easily measurable
parameter in the mid-1980s (Farquhar and Richards 1984). CID has been assessed for
various crops such as C3 cereals (Araus et al. 2002), maize (Gresset et al. 2014), soybean (Gitz et al. 2005), sorghum (Henderson et
al. 1998),
faba bean (Link et al. 2007)
and others. CID is an indicator of conservative water use and related to
earliness. It is therefore an important breeding trait for environments with
terminal drought (Condon et al. 2004;
Monneveux et al. 2005).
Higher intrinsic water-use efficiency can be related to both reduced stomata
conductance and higher photosynthetic capacity. The latter would combine water
saving with high yield potential, but is considered to be less variable in
plants beyond different photosynthetic pathways. Leaf chlorophyll concentration
(Rao et al. 2001;
Sheshshayee et al. 2006)
and specific leaf area (Rao et al. 1995;
Richards 2000),
however, are proxies for selection of genotypes with high intrinsic water-use
efficiency mediated by superior photosynthetic capacity.
Measurement of leaf temperature
has been used as a screening trait for sustained plant water supply (Blum et al. 1982) instead of direct measurement
of stomata conductance. In their original work, Blum et al. (1982) used leaf temperature to
screen for superior drought resistance of wheat. Mori et al. (2011) used infrared thermography to
analyse differences in root water uptake associated with a water-saving
behaviour of wheat in a Mediterranean climate. Hirayama et al. (2006) showed the strong negative
correlation of leaf temperature with transpiration and photosynthesis in upland
rice. Liu et al. (2011)
demonstrated the relation between leaf temperature and drought tolerance for
maize. Jones et al. (2002)
studied stomata closure in grapevine by infrared thermography.
Since the 1990s spectral
reflectance measurement has been increasingly used as screening approach for
the tolerance of various stresses (Carter 1993; Peñuelas and Filella 1998). For example, Winterhalter et
al. (2011)
estimated canopy water mass of tropical maize hybrids based on spectral
reflectance and showed that it can be used as a high throughput tool to
discriminate between groups with different drought resistance. Gutierrez et al.
(2010)
gives an overview of the relation of spectral indices such as NDVI, NDWI and WI
to plant water status measured by relative water content and/or leaf water
potential in different wheat genotypes. Araus and Cairns (2014) reviewed currently available
spectral technology and their use for field phenotyping. Beside plant water
status, reflectance indices are also used to predict other plant properties,
such as biomass growth and yield (e.g. Aparicio et al. 2000; Ma et al. 2001) and nutritional status of
crops (e.g. Filella et al. 1995;
Graeff and Claupein 2003;
Xue et al. 2004).
Water spending by improved
uptake has been shown to be an essential trait for better drought resistance,
particularly for intermittent stress. Efficient uptake of water addresses the
root system as essential breeding target (Vadez et al. 2007). Still, there are only few
examples where root traits have been targeted in breeding programs. Systematic
breeding efforts for root system properties have been done mainly for rice
(Price et al. 2002;
Kato et al. 2006;
Farooq et al. 2009a)
and chickpea (Kashiwagi et al. 2005;
Gaur et al. 2008).
For wheat, physiological and root research studies evidence the significant
contribution of roots to higher drought resistance (e.g. Sanguineti et
al. 2007;
Manschadi et al. 2008;
Palta et al. 2011).
Wasson et al. (2012)
give an overview of selection strategies for root improvement of wheat in
Australia. The lack of breeding activities on roots is mainly related to the
measurement problem, as there are few fast and cheap screening methods.
Existing high throughput approaches are mostly indirect (e.g. Středa et
al. 2012)
or ex situ (e.g. Hund et al. 2009b).
Still, roots are promising targets as (i) they are less exploited compared to
aboveground traits, (ii) most root traits are compatible with high yield
potential and (iii) there is considerable diversity (Trethowan and
Mujeeb-Kazi 2008;
Lopes and Reynolds 2010;
Nakhforoosh et al. 2014).
Recently, there is an increasing effort to establish high throughput root
phenotyping platforms to advance in targeted root breeding (Nagel et al. 2012).
3.6.6 Breeding
for dehydration tolerance
Dehydration tolerance is a
relevant trait for environments with intense water stress such as tropical
semi-arid and arid regions. Here, we emphasise on osmotic adjustment and cell
membrane stability as two widely used approaches to improve dehydration
tolerance in crops that have been used in breeding research. Osmotic adjustment
is a key response of plants to maintain cell turgorescence under conditions of
reduced water availability. By lowering osmotic potential, they increase the
water potential gradient to soil and thereby maintain water uptake and
expansive growth for longer time. Furthermore, osmotic adjustment enhances root
elongation in dry soil. An overview of measurement methods for osmotic
adjustment is given by Babu et al. (1999).
Blum (2005)
considered osmotic adjustment to be a main breeding target for stress
resistance due to its compatibility with high yield potential. A different
opinion on the role of osmotic adjustment has been expressed by Munns (1988) and Serraj and Sinclair (2002) considering that, beyond the
beneficial maintenance of root growth, osmotic adjustment is only effective as
survival mechanism under severe drought, i.e. under stress intensities beyond
the feasibility of rainfed crop production. Turner et al. (2007) did not find better yield of
chickpea under terminal drought due to osmotic adjustment. Sánchez et al. (1998) found that osmotic adjustment
partially explained turgor maintenance in pea cultivars under drought leading
to higher yield. Jongdee et al. (2002)
could not find a direct relation between variation in osmotic adjustment among
rice genotypes and their yield performance under drought. Chimenti et al. (2002), on the contrary, reported
that sunflower cultivars with higher capacity of osmotic adjustment had better
yield under drought. For wheat, Fischer et al. (2005) found a positive relation
between osmotic adjustment and yield for the highest stress level they tested.
Another
approach associated with severe drought conditions is cell membrane stability
(Blum and Ebercon 1981). It can be readily assessed by electrolyte
leakage (e.g. Bajji et al. 2002) and is
related to the concentration of compatible solutes like proline (e.g.
Valentovic et al. 2006). Singh et al. (1992)
found a correlation of yield of wheat genotypes under dry field conditions and
their differences in cell membrane stability under PEG-induced stress. Akbarian
et al. (2011) measured proline among other
physiological traits in triticale under tropical terminal drought conditions in
India and reported significantly lower yield losses with higher proline
concentration. Studies on membrane stability were frequently done under
osmotically induced stress (e.g. Lauriano et al. 2000)
and using young plants (e.g. Zlatev et al. 2006). While they
revealed important mechanisms and solutes underlying increased membrane
stability, a direct relation between these indicators and yield of drought
stressed rainfed crops in the field has to be taken with care. Particularly for
dehydration tolerance traits, a clear definition of the targeted stress
environment is of key importance to evaluate their potential use for crop
improvement. Box 8 highlights the potential of secondary traits for future
breeding advance.
Secondary traits for drought resistance
breeding
Breeding research for secondary
physiological traits has shown potential for better stress resistance in
water-limited environments. A bottleneck is high throughout phenotyping, which
has been successfully resolved only for some traits of potential interest.
Mainly drought avoidance via the root system still suffers from a lack of
screening methods. A challenge for the inclusion of new physiological traits to
crop improvement is to ensure their compatibility with high yield potential.
While yield constitutes a universal target trait for all environments,
physiological parameters require a precise understanding of the drought
environment to estimate their potential role for better crop performance.
Therefore, experimental design is particularly critical and extrapolation of
results from artificial laboratory conditions, such as shock stress and small
juvenile plants to the field has to be taken with care
Among agronomic measures tillage system, influencing both surface mulch cover
and soil porosity, together with optimised seeding dates to match water supply
and demand, are considered most effective. While tillage-induced effects on
soil hydraulic properties are similar under all climates, the water-saving
potential of mulch depends on the importance of evaporation losses with highest
efficiency under storage driven Mediterranean conditions. Stubble tillage is
relevant to reduce post-harvest evaporation mainly when some relevant amount of
rainfall occurs during the fallow period. However, the overall efficiency is
limited. Managing initial water depletion via crop rotation measures, e.g.
cover cropping vs. fallow, biennial rotations vs. fallow years or well balanced
wet and dry season crops, is of increasing importance the more a crop depends
on stored soil water. Therefore, the initial depletion level is crucial for dry
season crops in tropical and subtropical residual moisture regimes. The
importance of organic matter input for better soil water storage increases with
decreasing soil organic matter content. Compared to strong changes in soil
porosity from mechanical interventions via tillage, biologically mediated
measures are more complex. Still, they are a key for sustaining soil physical
quality and therefore integral part of any conservation tillage system.
Timely sowing is most important in climates where crop growth partially
or largely coincides with a dry season. The yield increasing effect of
optimised sowing dates is very consistent. Yield improvement via reduced stand density
on the contrary can be nullified by morphological plasticity of crops and risk
of suboptimum light use.
Breeding for adapted phenology and optimum assimilate partitioning
underlies much of yield improvements in water-limited environments. Among new
target traits for future breeding, we consider an effective root water uptake
as a key for success with importance for most dry ecosystems. Crops grown under
high intensity and continuous drought conditions, such as during post-monsoon
dry season in residual moisture environments, can profit from water saving
providing a balanced water use between vegetative and generative phase. Owing
to the prolonged stress periods, they also need sufficient dehydration
tolerance to sustain their metabolic functioning for yield formation and avoid
crop failure
NGO S' works are more towards people's drought proofing
and confined to individual support and those to community water structures,
grain distribution, cash doles, cattle camps, fodder distribution, health
camps, plantation and providing employment.
Simple employment generation plans are needed. Eradication of
mesquite (Prosopis juliflora) and lantana bushes (Viburnum lantana)
should be taken up to generate useable biomass based on native species. They
can also be used for food, fodder, thatching and fencing, herbal backup and as
raw material for craft and cottage industries. Solar energy, biogas plants and
other rural based economy generating jobs are the need of the hour during
droughts.
Preserving and developing traditional water
bodies should receive top priority with some kind of cost-effective mechanism
and the management and ownership of water bodies should be decided in advance.
Fodder banks have to be created in areas where natural pasturage is available.
Such pasturelands should be optimally used and harvested scientifically. The
procedure for deciding the relief beneficiaries needs to be revised.
Information cells should be opened at village and tehsil levels.
A nodal agency comprising ngo s and citizens should be formed to make
the relief agencies accountable. The issue of crop and livestock insurance has
to be decided as a coping mechanism. In the desert, rainfall records should be
maintained in schools so that there is no delay in declaring drought affected
zones.
If a modest beginning is made in these sectors
for rural poor, irrespective of caste and creed, the livelihood issues can be
addressed with positive results.
"... Small dams had preserved less water after rainfall
in the state. The percentage of water accumulated, in comparison to the total
capacity, was very less in small dams as compared to big ones... A small dam
was filled to only about 20 per cent of its capacity while larger dams stored
60 to 75 per cent."
At the Centre for Science and Environment, we
are part of a campaign called 'The People's Management of Water Programme'
where we are promoting community-based water harvesting. My colleague met the
scientist as we were keen to document experiences of communities involved in
water management and scientific data indicating the efficiency of small
structures and their drawbacks.
Subramanium claimed that he had visited three
districts in Gujarat where he found that the check dams had failed. These
districts were Rajkot and Bhuj. He had no scientific data to back his
statements.
Experiments in India,
the us and Israel have proved that 'small means more water'. In the
Negev desert, with a mere 105 mm of rain, a one hectare size watershed yielded
95 cubic metre (cum) of water per hectare (ha) per year. On the other hand, a
345 ha watershed, yielded a mere 24 cum of water/ha/year. The loss was high
since water in a larger catchment would have to run over a larger area,
implying evaporation and other losses. The loss was higher in a drought year,
which made small catchments a choice in drought-prone areas. A study in
Arizona, a semi-arid region in the us spanning two decades, revealed
there was a 99 per cent probability of getting an average annual runoff of 3.6
mm from a 1.3 ha catchment, whereas the runoff with the same probability from a
14,000 ha catchment was only 0.2 mm.
A study by the Dehra Dun-based Central Soil and
Water Conservation Research Training Institute (cswcrti) also indicated that
larger catchments resulted in lower runoffs. Even our reports based on visits
to drought-affected regions in Rajasthan and Gujarat show villages that have
harvested the rains have fared better than those who have not. Structures
whether big or small, cannot continue to supply the 'normal' amount of water if
rain fails for three consecutive years. But harvesting whatever little rain
that falls will definitely alleviate conditions. Activists are often accused of
being extremists, proposing unpractical and unscientific solutions. Well, we
have got our science right. Its time the scientists did
A seed
bank(also seedbank or seeds bank)
stores seeds to preserve genetic diversity; hence it is a type
of gene bank. There are many reasons to store seeds. One is to have
available the genes that plant breeders need to increase yield, disease
resistance, drought tolerance, nutritional quality, taste, etc. of crops.
Another is to forestall loss of genetic diversity in rare or imperiled plant
species in an effort to conserve biodiversity ex situ. Many plants
that were used centuries ago by humans are used less frequently now; seed banks
offer a way to preserve that historical and cultural value. Collections of
seeds stored at constant low temperature and low moisture are guarded against
loss of genetic resources that are otherwise maintained in situ or in field
collections. These alternative "living" collections can be damaged
by natural disasters, outbreaks of disease, or war. Seed banks are
considered seed libraries, containing valuable information about evolved
strategies to combat plant stress, and can be used to
create genetically modified versions of existing seeds. The work of
seed banks spans decades and even centuries. Most seed banks are publicly
funded and seeds are usually available for research that benefits the public.
Climate Change
Conservation efforts such as seed banks are
expected to play a greater role as climate change progresses. Seed banks
offer communities a source of climate-resilient seeds to withstand changing local
climates. As challenges arise from climate change, community based seed banks
can improve access to a diverse selection of locally adapted crops while also
enhancing indigenous understandings of plant management such as seed selection,
treatment, storage, and distribution.
In Nepal basic nursery management skills and
techniques to each community and helped it to establish a nursery.
Fast-growing, deep-rooted species are being promoted to control soil erosion in
bio-engineering sites. Gulmohar, khair, bains, amlisho, bamboo, bakaino, sisoo,
napier, moos, narkat, badahar, and Epil epil are some of the species grown in
nurseries and planted along riverbanks.
emergency and
first aid kits.
The
emergency supplies include life jackets, safety vests, throw bags, carabineers,
inner tubes, rope, helmets, hand-operated sirens, and stretchers. These
materials were put to good use during the last monsoon.
UP govt takes steps to help farmers hit by drought,
floods: UP Agri Minister
Uttar Pradesh government has
initiated several measures to help farmers whose kharif crops were affected by
drought and flood.
Uttar Pradesh government has
initiated several measures to help farmers whose kharif crops were affected by
drought and flood, state Agriculture Minister Surya Pratap Shahi said on
Friday.
The minister also said that the
state government is also looking at helping farmers raise production through
bumper Rabi crop.
"Ten thousand solar pumps
would be installed in Uttar Pradesh," Shahi said, adding that the share of
Mathura would be 40 solar pumps.
While the subsidy admissible
for for 2 HP or 3 HP Solar Pumps would be 70 per cent, for 5 HP or above solar
pumps, it would be 40 per cent.
He said, the state government
has decided to distribute 3.3 lakh mini kits of TORIA, Mustered, Rai or Laha,
Gram and Masur amongst flood /drought hit farmers.
Eighty-six thousand farmers of
Mathura were badly hit by drought would get these kits as per their
requirement, Shahi stated.
The size of these mini kits
vary from 2 kg to 16 kg depending upon the type of seed, he said.
For Rabi crop, Shahi said,
arrangements to distribute 44 lakh quintals of seed have been made. Around 7.3
lakh quintals would be distributed by government agencies.
Meanwhile committees consisting
of two ministers for two Kamishnaries (division) have been made to assess loss
owing to drought/flood for every area.
He said, the farmers would get
compensation on the basis of report of committees.
According to Shahi, 97,000
units of wormi culture would be set up in the state with provision for grant
for every unit. He said that at least one wormi culture unit would be set up in
every village.
The Uttar Pradesh government
has decided to grant subsidy up to 50 per cent for promoting "Khet
Talab" scheme for rain water harvesting in dark zone blocks, he said.
To counter the problem of
unemployment of BSc (Ag)/ MSc (Ag) pass youth, the state government gives grant
under Agri Junction scheme, if they take licence, open their shops, for selling
seed and fertiliser, he added.
According to Shahi, youth would
also get benefit of Rs 42,000 subsidy in three years, on bank loan of Rs 3.5
lakh.
The
state government has tried to provide relief to farmer through 'Rin Mochan
Scheme' (loan waiving scheme) and record purchase of wheat.
Shahi said that in the first phase of
loan-waiving scheme 11 lakh 95 thousand farmers have been benefited and an
amount of over Rs 7,400 crore has been distributed amongst farmers.
The second phase of
this scheme has also started, he said adding that "not only record
purchase of 37 lakh tonnes of wheat has been made this year but the farmers
payment has been ensured by transferring the amount into their accounts within
15 days," he said.
Almost every year, over 50 of the talukas in
Karnataka are affected by drought leaving principally the farming community and
their live stock at severe distress. The fodder deficiency during drought
results in reduced animal productivity, livestock death or distress sale
livestock. To mitigate the risk, the Government of India and the State
Government are supplying the fodder mini-kit containing fodder seeds to farmers
to grow improved variety of fodder. A case study of Chitradurga district in
Karnataka is carried out to assess the impact of fodder minikit distribution on
the production of fodder, benefits to farmers and livestock, prevention of
distress sale of livestock, as a drought mitigation measure,
Advantages Fodder Minikit ! Encourages the farmers
to grow fodder ! Farmers gets readily available input to grow fodder ! The
cultivated fodder supports the minimum fodder requirement of livestock. ! It
helps to sustain livestock productivity It also to motivates neighborhood to
reserve some part of land for cultivation
Disadvantages of Fodder Minikit
Inputs supplied are very meager and meets out the
fodder requirement of hardly 2-3 animals ! It requires irrigation facility
which creates a bias while selecting the beneficiaries ! At the time of drought,
supplied mini kits may not come to rescue of overcoming the fodder shortage. !
It requires man power which is not addressed for identification of
beneficiaries and supply of kits. ! Inputs supplied may not create big impact
to increase the overall fodder crop shortage.
