Water productivity analysis for cotton-wheat rotation
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Date
2006
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Publisher
CCSHAU
Abstract
Water productivity analysis aims at devising guidelines for producing more crop
from available water resources. In order to identify suitable criteria of water productivity
analysis, different existing criteria i.e. WPT, WPET and WPI were evaluated. An attempt
was made to identify the suitable criteria of water productivity depending on the objective
of the analysis. No single water management strategy is equally efficient in all conditions
due to spatial variation is hydrogeological properties. Therefore the study area Sirsa
district in Haryana state was schematized into a number of sub-areas (calculation units)
with the help of GIS technique using soil map, groundwater depth map and groundwater
quality map of Sirsa. From the simulation results it was observed that, both wheat and
cotton yield in light and medium textured soils, increased with increase in number and
depth of irrigation. However all the WPS of wheat and WPI of cotton decreased with
increase in number of irrigation. Due to rainfall fluctuation, year to year variation in wheat
yield was found to be more pronounced as compared to cotton yield as rainfall received
was less in rabi season in comparison to kharif season. There was no difference in yield
and water productivity values of wheat and cotton in light textured soils when either of the
canal water, good quality groundwater or submarginal quality of groundwater was used.
However reduction in yield was found for poor quality water use due to increase in soil
salinity in the root zone. In case of heavy textured soil, even with the application of
submarginal quality of groundwater, yield value decreased over the years. For less number
of irrigation, wheat yield in heavy soil (silt loam) was higher due to larger water holding
capacity as compared to light soil (sand). However yield value decreased in heavy soil with
increase in frequency of irrigation due to poor drainage characteristics of heavy soil in
comparison to light soil. As the study area is faced with typical problem like rising
groundwater levels in poor and marginal quality groundwater zones, declining
groundwater levels in the good quality groundwater zones due to over exploitation,
irrigation management strategy were recommended suitable to that area. In light textured
soil, where groundwater quality is good and water table is rising groundwater use was
recommended. In areas underlain with poor quality groundwater and faced with rising
groundwater levels conjunctive use of canal water and groundwater is recommended. For
heavy textured soil, simulation showed that less frequent irrigation with heavy depth need
to be followed to obtain maximum yield with the conjunctive strategy.