Pongamia a multipurpose leguminous tree containing non-edible oil grows widely in India. Oil extracted from the seeds of Pongamia is used as energy source as well as In tanneries while the cake (a by-product after extracting oil) was found to be rich in all plant nutrients in general and nitrogen (4.28%) and sulphur (0.19%) in particular. Both nitrogen and sulphur were found to be deficient in 100% and 80% soil samples from farmers' fields in Powerguda village of Adilabad district, respectively. Use of Pongamia seed cake as a source of plant nutrients for maize, soybean and cotton was found beneficial in participatory research and development (PR&D) trials on farmers' fields. Further, application of critically deficient micronutrients such as zinc and boron and secondary nutrient sulphur increased crop yields by 16.7% and 19% in soybean and cotton, respectively. Additional B:C ratios of 5.03, 1.81 and 2.04 were obtained for soybean, maize and cotton, respectively with use of cake as a source of N, however it needed higher initial investment.
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