Bhattacharyya, T and Chandran, P and Ray, S K and Mandal, C and Pal, D K and Venugopalan, M V and Durge, S L and Srivastava, P and Dubey, P N and Kamble, G K and Sharma, R P and Wani, S P and Rego, T J and Ramesh, V and Manna, M C (2008) Characterization of Benchmark Spots of Selected Red and Black Soils in Semi-Arid Tropics of India for Identifying Systems for Carbon Sequestration and Increased Productivity in Semi-Arid Tropical Environments: Global Theme on Agroecosystems Report no. 42. Monograph. International Crops Research Institute for the Semi-Arid Tropics , Patancheru, Andhra Pradesh, India.