The Indian economy largely depends on agriculture. The winter cropping season, also known as rabi, starts after the summer monsoon and continues up to spring or early summer months. Rainfall occurring at the end of summer monsoon season provides stored soil moisture for rabi crops, which are sown in the post-monsoon season (October-November). Variation in the frequency of heavy rain spell has a profound impact on the ecosystem. Therefore, an attempt has been made in this study to analyze the frequencies of moderate to very heavy precipitation events in India during the summer monsoon season (June through September) using a high resolution (1° x 1° latitude-longitude) gridded daily rainfall datasets prepared by the Indian Meteorological Department (IMD) and its association with rabi foodgrain yield, collected from the DES (2006).

The study indicates that a variation in the foodgrain production during rabi season in India is strongly linked to the variation in frequencies with respect to various fix threshold values of rainfall and shows positive correlation coefficients. However, its spatial coverage varies from threshold to threshold. Spatial coverage of positive correlations for the number of rainy days with rabi foodgrain production is more than the total precipitation of the summer monsoon season. Also spatial coverage of correlation coefficients and its level of significance decreases with increase in the threshold value of rainfall with respect to which frequencies are computed.

There are two major cropping seasons in India, namely, kharif and rabi. The kharif (summer) season crops are grown during summer monsoon period and harvested in the autumn or in early winter. The rabi (winter) cropping season starts after the summer monsoon and continues up to the spring or early summer months (Selvaraju, 2003). Summer monsoon season (June to September), the major rainy season of the country, provides major proportion of rainfall for the kharif growing season. Rainfall occurring at the end of summer monsoon season provides stored soil moisture for rabi crops which are sown in the post-monsoon season (October to November). The summer monsoon is therefore responsible for both the kharif and rabi crop production in India (Parthasarathy et al., 1988; Selvaraju, 2003; and Krishna Kumar et al., 2004). However, summer monsoon, June-September (JJAS), rainfall is sometimes scarce, sometimes plentiful, and always unevenly distributed in space and time. Year-to-year variability in summer monsoon precipitation has a major effect on the foodgrain production in India. The Indian summer monsoon is marked by heavy rain spells that occur due to the passage of monsoon depressions, cyclonic storms and other synoptic scale disturbances.

The agriculture year starts from June 1 and ends on May 31 of the next calendar year. The total foodgrains cultivated in the country are: (a) cereals (rice, wheat, sorghum, maize, pearl millet and finger millet); and (b) pulses (chickpea, pigeonpea, greengram and blackgram). Cereals form the core staple food and pulses are the protein supplement for the large vegetarian population. The major rabi crops are wheat and chickpea. Foodgrain production changes rapidly with time mainly due to the advanced technologies used in farming. Selvaraju (2003) has shown a rapid increase in wheat production and mentioned that this increase is due to the adoption of dwarf, high yielding and fertilizer responsive varieties.

Increase in the intensity and frequencies of rainfall events also has a large impact on the foodgrain production of the country. The Indian summer monsoon is marked by heavy rain spell that occur due to the passage of monsoon depressions, cyclonic storms and other synoptic scale disturbances, and each year, the monsoon brings large amounts of rain over most parts of the country in terms of moderate, heavy and very heavy rainfall events, while other parts of the country experience drought conditions. This rainfall distribution largely depends on the geographical conditions. Hills and mountain ranges over India display striking variations in rainfall. Hence extreme rainfall varies from place to place. The extreme rainfall event of one place can be a normal event for another place. However, change in the frequency of heavy rainfall events would have a profound impact on the nature. Analysis of the daily rainfall events during summer monsoon season reveals that heavy precipitation events are favorable for kharif crops for their lower frequencies and lower intensities and create adverse effect with higher frequencies and higher intensities (Preethi and Revadekar, 2009).

Soil And Water Sciences Journal, Summer Monsoon Precipitation, Foodgrain Production, Indian Meteorological Department, Wheat Production, Summer Monsoon Season, Rainfall Datasets, Agricultural Production, Winter Monsoon Precipitation, Regression Model, Weather Resource Management.