With profit margins potentially tight this coming year, some farmers may be looking for the minimum levels of phosphorus (P) and potassium (K) needed to ensure a strong yield. Soil tests are critical when micromanaging nutrient applications. If P is less than 15 ppm or K is less than 150 ppm, yields will be lower. Ideal levels for 180- to 200-bushel corn should be closer to 30 ppm of P and 200 ppm of K. If farmers choose to limit nutrient inputs, they must lower their yield expectations as well.
In the absence of nutrients, plants actually become more susceptible to pests and disease, which lowers yield potential. For instance, if soybean fields are low in potassium, the plants produce a nitrogen-heavy amino acid in the sap of the plant, which attracts aphids. Aphid infestations can result in heavy crop damage, dropping yields by as much as 10 bushels per acre. Nutrients are meant to help plants grow, making them stronger and much more resistant to stresses throughout the growing season.
Additionally, if farmers are choosing high-yield varieties, soil fertility is critical. If macronutrients are at minimum levels, the crop is already at a disadvantage. Be sure to plant high-yield varieties in the fields with the highest soil fertility — this provides a balance of nutrients for plants that will aggressively be taking them from the soil.
Balanced nutrition for plants is an ongoing responsibility. In fact, balanced crop nutrition is responsible for as much as 60 percent of yield. And it’s something that is built over time. A good nutrient management plan will not only address nutrient deficiencies for the coming year, but also help build up macronutrients over a period of several years. Micronutrients are managed annually, using soil tests as the guide. These proactive, comprehensive buildup programs are an economical approach to providing a consistent nutrient base for plant health, which results in consistency in resisting weeds, disease and pests year after year.
Although low commodity prices create an instinctive “tightening of the belt,” farmers are better off continuing to build soil fertility this growing season. Not only will this year’s yields be more fruitful, but the yields in the coming years will also prove to be higher. A committed, consistent investment in crop nutrition is one of the most sustainable business decisions a farmer can make.