Fertility – Reducing Fertilizer Costs
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- Use UAN products, such as 30 percent or 24S, for at least the side-dress application if not the entire nitrogen program.
- Apply no more phosphorus than recommended from the soil test. Over 90 percent of the soil test reports from tobacco fields in the coastal plain and 50 percent from fields in the piedmont recommended that fertilizer phosphorus not be applied. Growers reluctant to not apply any phosphorus can apply 5 pounds of phosphorus in the transplant water, which has been shown to equal the growth response of 40 pounds of phosphorus banded in the complete fertilizer (Figure 5-1).
- Based on current fertilizer prices, the most economical program involves the application of a potash material, such as potassium sulfate or potassium magnesium sulfate (or blend), to supply all of the potassium suggested by the soil test report and a UAN product to supply all of the nitrogen (Table 5-1). If soil phosphorus levels are high to very high, then no more than 5 pounds of phosphorus in the transplant water is sufficient to provide rapid early-season growth.
- Avoid products that add cost without improving profitability. For example the product Avail has been shown—under limited soil phosphorus conditions outside of the tobacco production region in North Carolina—to improve phosphorus uptake. However, phosphorus levels in most of our tobacco fields are very high. Studies conducted during 2008 showed no advantage of including Avail in the fertilizer for tobacco produced in fields with typical soil phosphorus levels