Tensiometer based irrigation scheduling in wheat (Triticum aestivum) in middle Indo-Gangetic plains

Abstract

The most common method of irrigation in eastern India is through tube wells with a fixed irrigation interval, irrespective of the soil type and climatic demand resulting in over-irrigation or under-irrigation under different soil and weather situations. Soil matric potential may be an ideal criterion for irrigation, since soil texture, cultural practices and water management affect wheat irrigation water requirements. The present study deals with the effect of tensiometer based irrigation scheduling on crop productivity of wheat. The experiment was laid out in factorial randomized block design (RBD) with two factors, viz. soil moisture potential at three levels of 20, 35 and 50 kPa and tensiometer depth of 20, 35 and 50 cm under furrow irrigated condition at ICAR-Research Complex for Eastern Region, Patna during 2013–16. Tensiometer readings were recorded on a daily basis and irrigation was applied accordingly. The highest wheat yield (4.1 t/ha) was obtained when irrigation was applied at 35 kPa at 20 cm depth. The highest water productivity of 1.809 kg/m3 was achieved under deficit irrigation (8.87 cm) with least grain yield (2.6 t/ha). Irrigation scheduling based at a pressure of 35 kPa at 20 cm or 20 kPa at 50 cm depth of tensiometer resulted in a significantly higher yield of wheat. Further field and modelling studies are needed to extrapolate the findings to a broader range of seasonal and crop conditions which will help in developing guidelines to assist farmers to schedule irrigation in wheat.