Here are eight tips to maximize the efficiency of your fertilizer dollars:
- In grass crops, such as corn, prioritize nitrogen. “If corn runs out of nitrogen, it’s over, regardless of phosphorus and potassium levels,” says Ken Ferrie, Farm Journal Field Agronomist, based in Heyworth, Ill.
- Don’t neglect sulfur. “In medium to low organic matter soils, you must maintain sulfur levels,” Ferrie says.
- Try not to deplete soil potassium levels. “While potassium doesn’t have as direct of a yield response as nitrogen, it impacts standability, water management and disease resistance,” Ferrie says. “Nitrates and potassium are tied together in the soil, so applying more nitrogen in pursuit of higher corn yields demands more potassium. Cutting potassium rates can decrease soil levels quickly, and it’s slow and difficult to build them back up.”
- “Compared to potassium, phosphorus offers more opportunities to increase efficiency, by using the 4R approach — right product, right rate, right time and right place,” Ferrie says. “Phosphorus is taken up throughout the life of a plant, but the most important part is taken up early in the growing season. A band of phosphorus, applied with the planter beside and slightly below the seed, is twice as effective as the same amount broadcast.”
- “Although timing and placement can make fertilizer more efficient, they don’t change the amount of nutrients the plant uses,” Ferrie points out. “One thousand bushels of corn requires 740 lb. of diammonium phosphate (DAP) and 380 lb. of potash (0-0-60); and 1,000 bu. of soybeans requires 1,565 lb. of DAP and 200 lb. of potash. If those nutrients are not replaced, levels in the soil will deteriorate.”
- “I’ve encountered farmers who have been told they could cut fertilizer rates by banding but didn’t realize the removal rate remained the same,” Ferrie says. “Years of cutting rates had drained the soil’s nutrient reserves.”
- If you apply two years of fertilizer, you can reduce yearly fertilizer costs by applying a lower rate every year. “Based on your soil test results, you can temporarily pull down soil values and then guide them back up again,” Ferrie says.
- With your profit goals in mind, study your soil test results to decide where you can cut fertilizer cost. “The best approach is to examine each zone in a field and pull back fertilizer rates on high-testing zones and maintain rates in low-testing areas,” Ferrie says.
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