Trade-offs between Farm Incomes and Soil Loss: An Application of Bio-economic Modelling in a Semi-Arid Watershed in South India

Abstract

Soil erosion is an economic problem and the cost of soil loss and its consequences could be very harsh. The major threat facing the sustainability and productivity is erosion and the associated nutrient loss through run off. And climatic shocks like drought and floods also aggravate the soil loss Aims: The study aims to bring out the different plans and the tradeoff analysis of the conservation and degradation through a multi objective framework. Study Design:  Primary data was collected from the farmers of the Padmaram watershed, in Mahbubnagaar district, Telangana state in south India. A detailed questionnaire was prepared which included the current management practices, the input costs and output prices associated. And the soil loss was estimated using the RUSLE equation. And the tradeoffs were obtained by the multiobjective linear programming (MOLP) Place and Duration of Study:  The padmaram watershed was selected, from kondurg mandal of Mahabubnagar district of Telanagana. Methodology: The multi–objective linear programming MOLP, is employed to get an efficient solution where in conflicting objectives are simultaneously optimized subject to constraints. The soil loss under different climatic scenarios were modelled using the CMIP data for 2020s,2050s and 2080s. The impact of climate change on soil loss and farm incomes were also assessed. Results: The operational land holding of a small farmer was 1.32 ha, medium famer about 2.71 ha and a large farmer about 4.99 ha. Cotton and maize were two major crops grown in the watershed holding an area of 56 per cent followed by paddy which occupies about 15 per cent. The major rabi crops were maize and rabi paddy (9 %). The cropping intensity of the watershed was 116.87 per cent. The soil loss from 60.0% of the watershed area was below 3.0 t ha−1 y−1.  The soil loss from 27.5% area ranged from 3.1 to 4.5 t ha−1 y−1 and remaining 12.5% area have soil loss more than 4.6 t ha−1 y−1. Soil loss and net returns for future climate scenarios were assessed. Conclusion: The analysis of trade off between production and conservation would be useful in identifying optimum crop plans with reduction in soil loss. The results stress that the interventions in agriculture have varying costs and environmental and economic impacts. Their implementation requires appropriate investment decisions.