Drivers and major changes in agricultural production systems in drylands of South Asia: assessing implications for key environmental indicators and research needs

摘要

The South Asian dryland(arid and semi-arid)ecosystem has been exhibiting considerable agricultural production system changes.There is scientific consensus that this nature of agricultural production system enables it to capture market,technologies and environmental opportunities.Pressing concerns are,however,adverse environmental trade-offs that these changes are experiencing and therefore the challenges toward a resilient agricultural production system.This is particularly important as arid and semi-arid ecosystems are resources constrained and thus more vulnerable: for example to climate change.To stimulate and revive a debate in agricultural research and policy circles,this paper demonstrates the magnitude of major changes,their drivers and environmental implications in context to agricultural production systems in dryland areas in South Asia.As an example we selected districts representing different dryland agricultural production systems in western Rajasthan,Andhra Pradesh and Karnataka states of India.Taking crop,livestock and trees as major enterprises,we characterized agricultural production systems of the sample districts.Key operational resources,demographic and external agents were illustrated as examples of drivers of changes.Major emphasis was given to material and environment related livelihood outcomes and their dynamic as agricultural production system evolves over time.Despite a remarkable improvement in material outcomes of agricultural production(＞ 100％increase in cereal grain yields taking 1966 as a base year),the long term environmental dimension tends to be compromised by short term needs: as demonstrated by perpetual soil nutrient stock mining,ground water depletion and instability of cereal grain yields(28-110％CV).Based on these empirical evidence,we debate as to where a system research should focus and what policy circles need to do to address emerging problems and contribute to advances toward a sustainable agricultural production systems in dryland.