Conservation agriculture for improving water productivity in Vertisols of semi-arid tropics

摘要

Large variability and uncertainty of rainfall are the\udmain limiting factors for crop growth in rainfed agriculture.\udAgriculture water management interventions\udare considered as suitable adoption strategy to enhance\udcrop yield, productivity and income in rainfed condition.\udThree-year experimental data collected at the\udInternational Crops Research Institute for the Semi-\udArid Tropics, Patancheru, India are analysed to study\udthe impact of in-situ interventions (tillage and crop\udresidue) on field water balance and grain yield under\udthe two different cropping systems (maize + chickpea\udsequential and maize/pigeon pea intercropping). One\uddimensional water balance model is calibrated to capture\udfield hydrology (soil water, surface runoff).\udWeather data calibrated for 36 years showed that incorporating\udcrop residues reduced surface runoff by\ud28% compared to control fields. However, the impact\udof tillage and residue treatment on soil water was\udnot consistent throughout the growing period. Water\udproductivity values for intercropping systems (WUE =\ud0.61 to 1.49 kg m–3) were relatively higher compared\udto sequential cropping systems (WUE = 0.47 to 1.06 kg\udm–3). Second crop in sequential cropping system often\udsuffered from water stress that led to poor crop yield.\udHowever, a few rain events at the end of the monsoon\udperiod were beneficial to second crop. Simulation results\udindicated that the conservation agriculture could\udsave up to 30% yield loss incurred due to water stress\udduring deficit rainfall compared to conventional agricultural\udpractices.