The major challenges in 21st century are food security, environmental quality and soil health. Besides, shrinking land holdings and increasing cost of inputs in India merit adoption of scientific use of plant nutrient for higher crop productivity. To address crop productivity through soil test based plant nutrient management, the ICAR project on Soil Test Crop Response has used the multiple regression approach to develop relationship between crop yields on the one hand, and soil test estimates and fertilizer inputs, on the other. Nutrient supplying power of soils, crop responses to added nutrients and amendment needs can safely be assessed through sound soil testing program. Soil test calibration that is intended to establish a relationship between the levels of soil nutrients determined in the laboratory and crop response to fertilizers in the field permits balanced fertilization through right kind and amount of fertilizers. To tide over the management problem of conducting field experiments at different sites, which differ from each other in the extent of uncontrolled variables, the project seeks to create artificial fertility gradients in 3 adjoining plots by applying different amounts of fertilizers to a preceding non-experimental crop. Then each of the three large plots is subdivided into subplots of which 3 are control plots, and 21 or 18 receive different quantities and combinations of fertilizer nitrogen, phosphorus and potassium, in a fractional factorial design. In 2005, the conclusion of a collaborative project with IASRI, New Delhi and recommendations of QRT suggested to adopt a new design. This design was constructed by keeping in mind to get various combinations of optimum doses for a given response. In this design the number of plots was same as those were in previous design, but some different treatment combinations were taken for experiment. Moreover, as recommended by QRT, one strip (L1/2 strip) was also dropped from experimentation. The final proposed design is Response Surface Design.
The project was started in 1967-68 with eight centers (New Delhi, Coimbatore, Pusa, Hisar, Hyderabad, Kalyani, Jabalpur and Ludhiana). During 1970-71, five more centers (Bangalore, Palampur, Pantnagar, Rahuri and Barrackpore) were added. One center (Raipur) was added during 1981-82. Presently, STCR project is working with twenty five cooperating/voluntary centers across India. The coordinating cell of the project was initially located at the Indian Agricultural Research Institute, but in April 1975, it was shifted to the Project Directorate, Central Research Institute for Dryland Agriculture, Hyderabad. Only in April 1996, it moved to its present location at Indian Institute of Soil Science, Bhopal.
Since its inception, ICAR-AICRP (STCR) strive for balance between crop productivity, farmers’ profitability, soil sustainability and better response ratio of applied plant nutrients for offering a diligent mix of crop productivity and soil sustainability which endeavours to give farmers the best of both world and opportunity for higher return based on resource endowment capacities. Besides, established linkages with state extension agency and recently through Schedule Tribe Component (erstwhile Tribal Sub Plan) activities have made headway for effective transfer of technology to the farmers. Also STCR-IPNS based long-term demonstrations under different agro-ecological regions proving the superiority of STCR approach of nutrient management.