Urea and Manure Effects on Soil Nitrogen and Corn Dry Matter Yields
1986
Xie, Rongjing | MacKenzie, A. F.
Fresh (FC) and composted (CC) cow (Bos taurus) manures, liquid hog (Sus scrofa domesticus) manure (HM), and urea (U) were applied as N sources for silage corn (Zea mays L., hybrid W844) production on a Chicot (Hapludalfs) and a St. Benoit soil (Eutrochrepts) at rates of 0 to 240 N ha⁻¹. Soil NO₃-N levels were significantly increased while soil NH₄-N levels were only temporary increased by N additions. Highest NO₃-N levels were noted 30 and 60 d (June and July) after N applications for the St. Benoit and the Chicot soils respectively. Hog manure resulted in more NO₃-N compared with FC and CC manures. One to 5 kg manure-N was found to be equivalent to 1 kg of urea-N in terms of increasing soil NO₃-N levels at the end of growing season. Differences between surface spreading or incorporating of manures on corn dry matter yields (DMY) and N uptake were not significant. Nitrogen uptake increased with increases in N application rates and was higher with HM than with CC or FC manures. Regression between DMY or N uptake and N application rates showed linear relationships with manure-N and quadratic relationships with urea-N. In 1984, 1 to 4 kg manure-N resulted in similar corn DMY as 1 kg urea-N. Cumulative effects of treatments on yields and on nutrient uptake observed in second and third years were greater on the St. Benoit soil than on the Chicot soil.
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