Farm Productivity Loss due to Flood-Induced Sand Deposition: A Study in Dhemaji, India

It is widely believed that the decline in agricultural productivity in the Dhemaji district of Assam, India, is due to flood-induced sand depositions in paddy fields. Increased sand content reduces the water retaining capacity of soils and reduces crop productivity. Soil tests in 346 agricultural plots in the Jiadhal basin of the Dhemaji district show high concentrations of coarse sand, low pH, low organic carbon and nutrients. Some 39% of the plots tested had sand concentrations greater than 70%. An analysis of the effect of sand on productivity suggests that sand deposits have a significant effect on paddy yields. The annual damage costs from sand deposition in the study area are estimated to range from INR 690 to 1845 (US$ 13 to 35) per hectare. This study underscores the need for further research to identify other factors that may also be responsible for the decline in paddy productivity in the region, while proposing interventions to improve paddy productivity.