Sulfur-coated Urea and Urea Compared as Nitrogen Sources for Irrigated Corn
1980
Sander, D. H. | Moline, W. J.
Sulfur-coated urea (SCU) was compared to urea (U) to determine their value as N fertilizers for irrigated corn (Zea mays L.) production. Two soils were studied from 1970 through 1972, Cass sandy loam (Fluventic Haplustoll) and Holder silty clay loam (Udic Arguistoll). Comparisons were made with different rates of the two fertilizers and the results interpretated in terms of yields, N uptake, and residual NO₃⁻-N in the root zone. Results of the study indicated little difference between the performance of the two N fertilizers in terms of grain, forage yields, or in N uptake although N from SCU tended to be less available than from U. After 3 years of application, more NO₃⁻-N was found in the root zone with SCU than U. This was especially apparent on the fine-textured Holder soil and to a lesser extent on the sandy Cass soil. While the increased NO₃⁻-N found after 3 years in the root zone did not affect fertilizer N need, data does suggest that SCU has potential for increased N efficiency by reducing leaching under moderate leaching situations. The data emphasizes the need for more accurate N recommendations that will access NO₃⁻-N in the root zone, N mineralization potential of the soil, and N in the irrigation water. It was possible to grow 92 to 94% of maximum corn yields without losses of N to the groundwater.
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