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retention or the reduced physical disturbance under conservation, reduced and NT
practices. Further, these practices have other benefits such as a reduction in produc-
tion costs, fuel consumption and machinery wear, which are considered more sus-
tainable practices in rainfed farming areas.
3.3 Water Management
Dryland areas are characterized by deficit and erratic precipitation with large spatial
and temporal variability. Ratios of evapotranspiration to precipitation are generally
high. As a result, moisture in the rooting zone of soil is normally low for most of the
year, thus limiting biological productivity in dryland areas (Srinivasarao et al. 2015 ).
As per an estimate (http://www.fao.org/ag/ca/training_materials/cd27-english/fme/
economic.pdf), soil moisture limits crop production in approximately three-quarters
of the worldʼs arable soils and is the main reason for low yields in the seasonally
dry, semi-arid tropics and subtropics. Soil moisture management is, therefore, a key
factor when trying to enhance agricultural production in dryland areas. Proper man-
agement of water determines the allocation of rainfall to the soil for primary pro-
duction. The conservation of soil and water in dryland areas is inter-related. Dryland
areas, therefore, need concerted effort and strategies to increase water infiltration
into the soil by reducing runoff, minimizing evaporation rates and improving water
availability and use efficiency in the root zone through improved soil management.
The capacity of soil to hold plant-available water depends on its texture, depth,
structure (pore space), organic matter content and biological activity. Soils with low
organic matter and shallow aerobic zones have a low water holding capacity and
oxygen content, and are compacted. These conditions hamper root development and
usually indicate low microbial activity. Depleted levels of organic matter have sig-
nificant negative impacts on water use efficiency due to poor porosity and infiltra-
tion, local and regional water cycles, plant productivity, the resilience of
agroecosystems and global carbon cycles (Wani et al. 2009 ). The abundance of soil
microbes is directly proportional to organic matter content, both of which improve
soil texture and structure. Thus, soils receiving large amounts of organic residues
can support a larger microbial population. By controlling infiltration rates and water
holding capacity, soil organic matter plays a vital function in buffering yields
through climatic extremes and uncertainty that exist in dryland areas. The applica-
tion of microorganisms also improves soil organic matter and soil structure leading
to less clodding and crusting. Agricultural practices such as conservation agricul-
ture that improve soil structure and soil biological parameters also improve soil
moisture (Benites and Castellanos 2003 ).
M. Grover et al.