Soil-based fertilizer recommendations for precision farming.

In India, current fertilizer recommendations are very old and developed based on agro-climatic zones. The assumption is that agro-climatic zones are homogenous units. However, analyses of agro-climatic zones reveal variability in soil within each zone. Current agro-climatic zonal fertilizer recommendations are generalized for entire zone and not addressed to specific soil types. To know the soil variability within the National Agricultural Research Project (NARP) agro-climate zone and suitability of current fertilizer recommendations, sugarcane in northern dry zone of Karnataka was studied as a test crop. The results indicated that agro-climatic zones vary widely in soils and in their potentials, behaviour and response to management. It was also observed that fertilizer application efficiency varied within each zone and within the management units. These differences contributed to errors of both excess and insufficient applications. Besides, there is a continuous removal of secondary and micronutrients by crops in all farming situations resulting in inappropriate management practices. All these suggest that soil-based fertilizer recommendations should be preferred to achieve precision in farming and to maximize crop production, maintain soil health and minimize fertilizer misapplication. [ABSTRACT FROM AUTHOR]