Crop Information

Four key items unique to each crop impact P and K fertilizer recommendations and lime requirement:

• The P and K demand level for the crop. Each crop requires varying levels of available P and K to optimize yield. Crops are placed into one of four P and K demand levels based on their relative nutrient needs: 1) corn, soybean, small grains (but not wheat), grasses, oilseeds, and pasture; 2) alfalfa, corn silage, wheat, beans, sweet corn, peas, and fruits; 3) tomato, pepper, brassicas, leafy greens, and root, vine, and truck crops ; and 4) potatoes. The demand levels for specific crops are identified in Table 4.2. 
• The amount of phosphate (P₂O₅) and potash (K₂O) removed in the harvested portion of the crop is used to establish the amount of fertilizer to apply. Table 4.2 lists the amount of P₂O₅ and K₂O removed in pounds per unit of yield. 
• The yield goal for each crop is required to determine the application rate of P₂O₅ and K₂O fertilizer for all crops and the nitrogen (N) fertilizer rate for potatoes. Realistic yield goals should not be higher than 10 to 15% above the previous 3- to 5-year field average. Typical yield ranges and the moisture content at which yield is reported are provided in Table 4.2. 
• Target pH is the optimal pH for production of a particular crop. Target pH is used to determine lime requirement and other pH adjustments. Refer to Table 4.2 for target pH values for various crops.

Table 4.2 – Crop codes, typical yield range, moisture content at which yield is reported, phosphorus (P) and potassium (K) crop removal values and demand levels, and target soil pH values for each crop.