Soil fertility evaluation to assess the nutrient status of a soil can be considered as the key factor to fertilizer and manure recommendation. In the present era of increased environmental damages and declining soil productivity due to indiscriminate and non judicious use of fertilizers and enhanced fertilizer cost, soil test based fertilizer recommendation deserves special attention. Precision farming approach to find out fertlizer recommendations to achieve a targetted yield is another technology available today. A more precise recommendation which is specific to soil test data, yield target and planting season is available today
Site specific nutrient management means supplying plants with nutrients to optimally match their spatial and temporal need for supplemental nutrients. It can increase profit by higher yields, higher nutrient use efficiency (output/input), reduced incidence of diseases and pests and is environment friendly. Nutrient management of cassava by blanket fertilizer recommendations over wide areas and soil types over the past 40 years or so in India have resulted in significant yield increase. But when we extrapolate the results from experimental stations to farmers’ fields, the yield cannot be increased beyond a certain level due to the high temporal and spatial variability of soil and plant properties. Studies clearly showed that further increase in yield and nutrient use efficiency can be possible only by managing this large spatial and temporal variability existing in soil nutrient supply, nutrient use efficiency and crop response to nutrients among different farms.