CLIMATE AND LANDUSE CHANGE IMPACTS ON SUB-SEA LEVEL RICE FARMING IN A TROPICAL DELTAIC WETLAND

摘要

Sub-sea level paddy farming system practiced 2-3 meters below sea level in the fertile Kuttanad delta situated in the west coast of peninsular India is a unique and globally important agricultural heritage system. This vast tropical estuarine complex is drained by five Western Ghat rivers and is also part of the largest Ramsar site in India. The present study investigates the historic trends in landuse and climate on agricultural production from this unique wetland paddy system over the past 48 years (1966-2014). A supervised classification of Landsat images revealed the drastic changes to landuse in the delta over the past four decades. Two distinct phases of land reclamation are identified: reclamation of land from the natural wetland estuaries for paddy cultivation as well as the more recent paddy land conversions into uplands. The statistical trend analysis of climate variables of temperature and precipitation on paddy yield for the time period in the region revealed weak and insignificant impacts of warming climate on agricultural production from this wetland system. It is observed that in the near term, anthropogenic land use changes have stronger significant impacts on the delta than the impacts of climate change. Such a historical assessment of observed data on climate and landuse is critical for devising sustainable strategies and adaptive mechanisms for the conservation of this valuable agricultural system.