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Irrigation of a field is normally warranted when the available moisture content in the root zone of a crop is depleted by about
Conjunctive use of water in a basin means
Net irrigation requirement of a crop is equal to
Net Irrigation Requirement (N!R) is the amount of irrigation water required in order to meet the evapotranspiration need of the crop as well another, needs such as leaching. Therefore, NIR = Cu - Re + Water lost as percolation in satisfying other needs such as teaching.
In an irrigation system, water was delivered to the field in ditches spaced about 30 m apart, and was allowed to seep into the ground to maintain the water table at such a height that the water is available to the crops through the capillary fringe. This method of irrigation is called.
When a system of open jointed drains is artificially laid below the soil, so as to supply water to the crops by capillarity, then it is known as artificial sub-irrigation. It may be recommended only in some special cases with favourable soil conditions and for cash crops of high return.
In contour border irrigation method
In border method of irrigation, the flow along the border is a case of
In an irrigation system, the land was divided into a large number of smaller size unit areas, having fairly level surface, by bunds and cross ridges. The basins thus created were filled with water to the desired depth and the Water was retained for some time. This method of irrigation is known as
Check flooding is similar to ordinary flooding except that the water is controlled by surrounding the check area with low and flat levels. Levels are generally constructed along the continuous having vertical interval of about 5 to 10 cm.
This method is suitable for more permeable soils as well as for less permeable soils. The water can also be held on the surface for a longer time in case of less permeable soils.
For growing irrigated paddy, the ideal water application method is
The maximum application rate by sprinklers is limited by
Which of the following statements pertaining to sprinkler irrigation is not correct?