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Subsistence agriculture practice and a combination of harsh climate and fragile soils along with increasing demographic pressure are matters of great concern from the viewpoint of resource management and longterm sustainability in the semi-arid tropical Alfisol soils of India. In this study, soil quality index (SQI) has been computed on 190 sites of farmers' fields in southern India to evaluate the possible effect of land management practices on soil degradation and determine the critical levels of soil organic C stock to maintain a desirable SQI and also suggest appropriate management practices. In all, 26 predominant physical, chemical and biological properties of soils were studied and based on principal component analysis, moisture retention at field capacity, available soil N, available P, DTPA-extractable Zn, exchangeable sodium percentage, C-mineralization and bulk density were identified as the key indicators of the study region. SQI was also computed using four soil functions, viz. nutrient cycling, availability of water, resistance of soil to degradation, and salinity and sodicity. Soil resilience index was computed using data on substrateinduced respiration after exposing the soil to heat stress. SQI was highest under paddy followed by permanent fallow, maize, cotton, intercropping, redgram, and was lowest under castor system. Based on the results, it was observed that the soils which had higher SQI were also productive and they exhibited higher resilience capacity. An amount of 8.6 Mg ha -1 soil organic C stock per 15 cm depth was found essential to maintain soil quality and 2.2 Mg ha -1 of organic matter was needed every year to maintain this stock. On-farm participatory research trial was conducted using SQI as a tool for sustainable land-management practices.

This book series provides complete, comprehensive and broad subject based reviews about existing biodiversity of different habitats and conservation strategies in the framework of different technologies, ecosystem diversity, and genetic diversity. The ways by which these resources are used with sustainable management and replenishment are also dealt with. The topics of interest include but are not restricted only to sustainable development of various ecosystems and conservation of hotspots, traditional methods and role of local people, threatened and endangered species, global climate change and effect on biodiversity, invasive species, impact of various activities on biodiversity, biodiversity conservation in sustaining livelihoods and reducing poverty, and technologies available and required. The books in this series will be useful to botanists, environmentalists, marine biologists, policy makers, conservationists, and NGOs working for environment protection.More information about this series at

To meet the requirement of increasing demand for food and fodder and to ensure food security, it is important to increase the production potential through soil health improvement in rainfed agroecological regions besides the irrigated regions. Degrading soil health because of decrease in soil organic carbon (SOC) and resultant decline in overall soil fertility in rainfed areas is a major threat to sustenance of crop and fodder productivity. In view of the importance of soil organic matter (SOM), and its close relationship with soil health and crop production, its role in carbon sequestration and nutrient cycling has gained much attention in the last few years. Restoration of SOM contents in the soil to optimal levels will not only improve the soil health of rainfed agroecosystem, but will also significantly contribute towards boosting crop production. In this article, we have critically reviewed the impacts of different crop management practices on SOC content and its impact on soil health and crop productivity in rainfed agroecological regions of the country.

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