12-10-2010, 12:53 PM
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HARVESTED RAINWATER IN SEMI-ARID
M. K. Khandelwal1,S. K.Shakya2, R. H. Ghaghada3, and G. R. Sharma4
Abstract:
A situation specific computer programme incorporating hydraulic design and
hydrological criteria, set of different runoff coefficient, CN=88 for runoff generation and
USDA,SCS,CN method is incorporated to design parameters for water harvesting structures
at title watershed. The computer programme is used with average of the daily rainfall time
(1971-97) to compute probable quantity of water that could be available by the end of
estimated date of harvest. Recommended agronomic measures (crop coefficient, dates of
sowing & harvest, duration, critical crop growth stages) for the specified regions are
considered to compute water requirement and irrigation scheduling (at 66.67% field
application efficiency) of prevailing crops in the regions under a variety of conditions (i) no
deficiency of irrigation water (ii) yield reduction by 10%, and (iii) yield reduction by 20%.
Gross returns, net returns on cost of cultivation and output input ratio at cost ‘A’ of all the
prevailing crops (based on average of data 1980-81 to 1997-98), water requirements of crops
and probable available water in the structure by the end of estimated date of harvest are used
to formulate the linear programming problems which have been solved by stepwise
optimization technique. The results suggest a set of optimal plans (alternatives) for
cultivation during either Kharif or Rabi only, under different specific conditions. Application
of the problems to an existing irrigation tank 'B' and comparison of the results reveal similar
crops selection for cultivation during both the seasons. These solution can also be adopted for
better agricultural production under similar situations elsewhere.