HR: 0800h
AN: H21E-1396    [Abstracts]
TI: Irrigation Scheduling Based on Soil Moisture Studies and Crop Yield Under Deficit Irrigation
AU: Rao, K
EM: kvj@nitw.ernet.in
AF: Research Scholar, Water & Environment Division Department of Civil Engineering National Institute of Technology , Warangal, AP 506 004 India
AU: * Jayakumar, K
EM: kvj@nitw.ernet.in
AF: Professor, Water & Environment Division Department of Civil Engineering National Institute of Technology , Warangal, AP 506 004 India
AB: A critical element in irrigation scheduling is the accurate measurement of the volume of water applied or the depth of application at a predetermined frequency. The problem arises when there is deficit in the availability of water for the desired cropping pattern. A live problem in a distributory of a major irrigation project in the State of Andhra Pradesh in South India has been taken up for the present study. A software "SOMOSIM" (Soil Moisture Simulation) has been developed as a part of the study to determine the frequency and depth of irrigation. This program is then combined with the software B2D developed by Playan et al (1994) to determine the discharge required and corresponding duration to store a design depth of irrigation in a prescribed dimensioned strip of land. The study is carried for different levels of deficits and adopting various cropping patterns prescribed by statutory bodies and funding agencies. Sensitive factors of different crops, suggested by FAO are also taken into consideration for various stages of crop growth in the computation. Necessary data for this study were obtained from the agricultural university, agricultural research station and the agriculture marketing department. The results of the study indicate a scientific allocation of water under deficit conditions. When the deficit is large and if the crops are very sensitive for shortage of water, such crops may not be grown. Four approaches are used in the study for distribution of deficit, viz.,  Distribution of deficit equally among all the crops  Distribution of deficit on the basis of weighted average of sensitive factors  Distribution of deficit on the basis of relative weights of sensitive factors, and  Distribution of deficits to achieve constant relative yield. The study shows that the fourth method is the best among the various methods tested.
DE: 1804 Catchment
DE: 1821 Floods
DE: 1847 Modeling
SC: Hydrology [H]
MN: Fall Meeting 2005