Acceso usuarios
S.K. Behera, P.K. Panda, P.S. Kashyap
Scarcity and growing competition for fresh water resource will reduce its availability for irrigation. At the same time, the need to meet the growing demand for food will require increased crop production using less water. Regulated deficit irrigation provides a means of reducing water consumption while minimizing adverse effects on yield. The reported study was undertaken to determine an efficient strategy for management of irrigated wheat under water stressed conditions, in a sub-tropical sub-humid region. Field experiments were conducted on the crop over a period of 3 years with five different irrigation treatments. Layer-wise soil moisture status was continuously monitored to determine the crop water extraction pattern and hence the optimum irrigation management depth. Irrigation treatments consisted of different levels of depletion of available soil water. The five levels of depletion considered in the study were 10, 30, 45, 60 and 75%. CERES-wheat growth simulation model was calibrated and validated for further use. In order to asses the depth and time variation of soil moisture under different scheduling of irrigation, soil moisture was measured periodically in 15¿30, 30¿45, 45¿60, 60¿90 and 90¿120 cm soil layers using a neutron probe, while the soil moisture in 0¿15 cm soil layer was determined by gravimetric method. It was observed that the plants extracted most of the soil moisture from 0 to 45 cm soil layer. Therefore, it is recommended that only 0¿45 cm of soil layer be considered for scheduling of irrigation for wheat grown in sandy loam soil in a sub-tropical regions under water scarcity conditions. The field water use efficiency of wheat was found to be the highest when irrigation was scheduled at 45% depletion of available soil water (ASW). It is therefore recommended that under the condition of water scarcity, plant extractable soil water depletion of more than 45% of ASW must be avoided during non-critical stages. The calibrated CERES-wheat model was found to be quite efficient in the simulation of yield parameters and layer-wise soil moisture extraction pattern. It can therefore be successfully used for decision making in the region.
Author Keywords: Irrigation; CERES-wheat model; Validation; Water balance; Depletion level; Water use efficiency
