Effect of Added Urea and Potassium Chloride on Yields of Corn over Four Years and on Soil Potassium
- A. F. MacKenzie ,
- L. E. Phillip and
- P. C. Kirby
- D ep. of Renewable Resources, Faculty of Agric., Macdonald College of McGill Univ., 21111 Lake Shore Rd., Ste. Anne de Bellevue, P.Q., Canada H9X 1C0
D ep. of Animal Sci., Faculty of Agric., Macdonald College of McGill Univ., 21111 Lake Shore Rd., Ste. Anne de Bellevue, P.Q. Canada H9X 1C0
D ep. of Renewable Resources, Faculty of Agric., Macdonald College of McGill Univ., 21111 Lake Shore Rd., Ste. Anne de Bellevue, P.Q. Canada H9X 1C0
Silage corn (Zea mays L.) is a major crop in eastern Canada, and yield increases due to added N and K have been noted. However, possible interaction between N and K, and the effect of weather conditions on yield response and maturity must be determined for rational use of N and K fertilizers. A fertilizer experiment on the production of silage corn using urea and KCI was established on an Ormstown silty clay loam (fine silty, mixed, non-acid, mesic Typic Humaquept) for 4 yr. Rates of fertilizer were 0, 90, and 180 kg N ha−1, and 0, 60, and 120 kg K2O in the first 2 yr, increased to 0, 120, and 240 kg K2O ha−1 in the last 2 yr. Yields of silage corn were increased with N in 3 yr and with K in 2 of the 4 yr. An interaction between N and K was found in the years when there were yield responses to added KCl, indicating that increased crop yields with K occurred only at relatively high N rates. Added N increased dry matter contents of corn plants, whereas added K reduced dry matter contents at low rates of N. Relative yields of the control plots over the high N-K plots were correlated positively with precipitation during the growing season. Added urea when combined with added KCl increased exchangeable and soluble K, probably due to reduced K fixation by illite, mica and vermiculite minerals in the soil.
Copyright © . .