Correcting Iron Deficiency in Corn with Seed Row–Applied Iron Sulfate
2003
Godsey, Chad B. | Schmidt, John P. | Schlegel, Alan J. | Taylor, Randal K. | Thompson, Curtis R. | Gehl, Ronald J.
Corn (Zea mays L.) grown on calcareous, high-pH soils is susceptible to Fe deficiency, which can reduce grain yield by as much as 20%. The objective of this study was to evaluate several treatments of FeSO₄ that could be used with precision-farming technologies to alleviate Fe deficiency in irrigated corn. Three sites in 1999 and four in 2000 were selected (based on a history of Fe deficiency) for small-plot (3 by 12.2 m) studies in western Kansas. In 1999, five treatments, including four rates of FeSO₄·H₂O (0–81 kg ha⁻¹ product) applied in the seed row and one foliar treatment (chelated Fe), were evaluated. In 2000, two additional treatments, CaSO₄·2H₂O (85 kg ha⁻¹ product) and liquid FeSO₄·7H₂O (91 kg ha⁻¹ product) applied in the seed row, were included. Grain yield increased linearly with increasing rates of FeSO₄·H₂O at four of seven site-years, increasing 0.02 Mg ha⁻¹ for each kilogram per hectare of FeSO₄·H₂O applied. Based on yield responses observed in this study, 81 kg ha⁻¹ FeSO₄·H₂O was the most consistent treatment for correcting Fe deficiency in corn. If the average yield response obtained in this study can be achieved on 15% of an individual cornfield, the expected return would be $3.00 ha⁻¹ for the entire field. Current precision-farming technologies allow application of FeSO₄·H₂O only to areas susceptible to Fe deficiency. Employing these technologies provides a practical solution to the spatial heterogeneity of Fe deficiency in irrigated corn and increases the probability of crop response to the fertilizer application.
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