Discerning shifting irrigation practices from passive microwave radiometry over Punjab and Haryana

Overexploitation of groundwater (GW) in the recent past is a well-known fact for the Punjab and Haryana region of India, as reported by several studies using satellite-based gravity anomaly from the Gravity Recovery and Climate Experiment mission and also by using observed data. This decline in GW has enforced the Punjab Preservation of Sub-Soil Water Act 2009, and resulted in change in rice irrigation practices over the study region. In this study, a shifting pattern of irrigation practices has been detected during pre- and post-Water Act using high temporal passive microwave radiometer (Advanced Microwave Scanning Radiometer - Earth Observing System, AMSR-E) and optical data. Multi-year soil moisture data for the period May to September were analysed for the years 2002 to 2011. A shift in the early soil wetness pattern has been observed during 2002 to 2011 in most of the study region. The overall delay in irrigation practices was observed to be 10 +/- 4 days over Punjab and Haryana in the pre-and post-Water Act implementation. Multi-temporal passive microwave radiometry was found to be expedient for observing the dynamic pattern of irrigation/agricultural practices over Punjab and Haryana states.