Rice cultivation in saline tracts of Kerala: An overview

Abstract

Salinity is one of the most important abiotic constraints that limit plant growth. It also affects the development, productivity and yield of crop plants. Salinization is a wide spread phenomenon in irrigated agriculture in countries of almost all the continents. Large proportions of both rainfed and the irrigated land face the threat of an increase in concentration of dissolved salts in the soil profile to a level that impairs food production, environmental health and socio-economic wellbeing, due to either natural or human-induced causes. Over 15% of the world’s cultivated land is affected by either salinity or sodicity and the problem is ever increasing. Rice is feeding more than half of the world’s population. One fifth area of Kerala state of India is wetland and there are about 217 wetland areas in Kerala which include the unique ecosystems like marshy and water logged areas, vast paddy cultivation areas associated with backwaters and lakes. The coastal saline soils of South India are highly underutilized because the use of ground water for normal crop production is not possible due to the poor water quality. At present, the entire coastal area is mostly monocropped during the monsoon period with rice as the only crop. The land remains fallow during the rest of the year due to lack of good quality irrigation water and high soil salinity. Thirty seven percent of rice production in the state is contributed by the lowland ecosystems. This paper is an effort to review the Pokkali and Kaippad systems of rice cultivation in Kerala which is significant presently since the wetlands under rice-fish farming have been facing severe threats due to a variety of factors including shift from the ecologically fragile rice-fish farming to semi intensive fish farming.