The influence of Indian Summer Monsoon precipitation on crop productivity in the Indo-Gangetic Plain

摘要

Over the next 50 years a projected rapid increase in India's population will increase pressure on food producing areas in the country, primarily the Indo-Gangetic Plain. Climatic parameters, specifically Indian Summer Monsoon (ISM) rainfall, exert a significant control on agricultural production. With little area available for expansion and under the influence of climate change it will be challenging for this region to meet these demands. The ISM climatic event is critical to Indian agricultural production providing water for rainfed (kharij) crops and irrigation water and soil moisture for rabi crops. An improved understanding of how the ISM impacts upon crop production is vital to wider efforts to ensure food security for India's growing population. This study identified trends in the ISM over the last four decades and will link these trends to changes in productivity in the Indo-Gangetic Plain. Using 0.25° gridded APHRODITE daily precipitation data, trends of various facets of monsoon functioning were investigated for the period 1970 - 2007. Spatial and significant temporal trends of total monsoon rainfall, onset date of monsoon, frequency of extreme rain events and drought years were identified for all India. This analysis snowed that interannual variation has exerted a greater influence on monsoon functioning in terms of date of onset and frequency of drought days than any significant trends associated with climate change. The North-West Region of India has had a significant trend of decreasing total monsoon rainfall from 1970 - 2007; this area coincides with the Thar Desert indicating increased risk of desertification, but also parts of Punjab, an area of intensive agriculture and extensive use of irrigation resources. The monsoon related variables were correlated with measures of productivity from AVHRR data over the Indo-Gangetic Plain for the past 30 years. This provided a detailed understanding of the aforementioned facets of monsoon functioning on crop productivity. This information is useful to inform modelling of crop growth under climate change and management of food systems to preserve environmental sustainability whilst meeting an increased demand for food.