Prioritizing soil conservation measures based on water erosion risk and production and bio-energy losses in peninsular South Indian states

Critical soil erosion risk areas in peninsular southern Indian states were identified through integration of biophysical and productivity loss following a robust scientific procedure (weighted average). Biophysical priority as a function of difference between soil erosion and corresponding soil loss tolerance values at a given location were redefined into three soil erosion risk classes, namely Low, Mid and High. Cumulative productivity losses, due to water erosion, of major crops grown in the area were also prioritized and an overall harmonization was made by integrating the two datasets. Analysis revealed that Kerala is suffering the most with a loss of 4.8 q ha(-1) followed by Karnataka (2.7 q ha(-1)), Andhra Pradesh (2.1 q ha(-1)) and Tamil Nadu (1.8 q ha(-1)) which is equivalent to annual production loss of about 2.31 M t of cereals, 0.83 M t of oilseeds and 0.52 M t of pulses due to water erosion. As per the weighted methodology, all states fall under Mid Priority class since the weighted values of these states are less than or equal to country's weighted value (16 t ha(-1)), but higher than half of the difference (i.e. 8 t ha(-1)) between weighted India value and lowest non-priority value (zero t ha(-1)). The energy loss in terms of aboveground biomass of all major crops has been estimated as 152 tera joules. The estimated production and energy losses due to soil erosion would greatly help in taking informed decisions for implementing appropriate conservation measures at local, regional and global level as the problem of soil erosion has not been addressed in an integrated manner so far.