Page 42 - soil-plant-water relationship and water requirement
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SOIL-PLANT-WATER RELATIONSHIP AND WATER REQUIREMENT
CHAPTER 4
4.0 CROP GROWTH CHARACTERISTIC
4.1 WATER, CROP YIELD AND QUALITY
Water is merely one of several factors that must be considered in order to attain the
ideal crop yield and quality. The quantity of yield per unit of area per unit of water, for
example, 30 kilograms of wheat per acre per acre-inch of applied water, is a practical
measure for water use efficiency.
Maintaining an acceptable depletion range (ideally less than 5 bars tension) in the soil
gives the intended yield and quality in most cases. The impact on yield and quality is
determined by how severe the water deficit is and when it happens during crop growth.
Excess irrigation water applied above and beyond what is required to cultivate a
profitable crop does not boost yields and, in most cases, reduces yields.
Other variables that may affect crop productivity include a shortage of adequate
nutrients, trace elements, and uncontrolled pest activity. Excess irrigation water can
cause important plant nutrients, herbicides, and their metabolites to leak below the
root zone. Ground water can be contaminated by excess irrigation water percolating
below the root zone.
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