Description

The basic purpose of soil fertility evaluation is to provide information on the nutrient status of the soil and predict the relative response to added nutrient. The Crop Nutrient Requirement (CNR) values are those amounts of nutrients needed to produce optimum, economic yields from a fertilization standpoint. It is important to remember that these nutrient amounts are supplied to the crop from both soil and fertilizer. The amounts are applied as fertilizer only when a properly calibrated soil test indicates very small extractable amounts of these nutrients to be present in the soil.

The nutrient status of cropped soils is variable and continually changing due to the influence of fertilizer addition, nutrient losses by leaching or removal, and overall management. Site-specific estimates of the nutrient fertility status of soil are, therefore, very important to rational fertilizer use. Reliable site-specific information can only be accomplished through an orderly program of soil fertility evaluation in which proper attention is given to the following : 1) techniques of soil sampling; 2) methods of soil analysis; 3) system for correlation of soil analysis and crop response; 4) model for interpretation of fertilizer response in field trials, and 5) procedure for preparing economically sound fertilizer recommendation. The objectives of this study are to build environmentally friendly fertilizer recommendations based on soil analysis for vegetable production in ultisol Jasinga. The Best Management Practices (BMP) for fertilizer recommendations based on soil analysis are not available for Indonesian vegetable farmers.