Yield and Botanical Composition of a Grass-Legume Mixture on Reclaimed Land as Affected by N and P Fertilizer1
- G. A. Halvorson and
- A. Bauer2
The study was conducted to determine the effect of fertilizer N and P on a grass-legume mixture grown on land reclaimed following strip-mining. Phosphorus was broadcast at rates of 0,6,17,50, and 150 kg P/ha in the fall of 1974. One-third of the plots which received 6, 17, or 50 P/ha received no additional P during the course of the study; one-third received an additional broadcast application of 6, 17, or 50 kg P/ha, respectively, in the spring of 1976 and one-third received 6,17, or 50 kg P/ha, respectively, in the spring of each year from 1976 to 1981. Nitrogen was applied annually in the spring, on the same plots, beginning in 1975, at rates of 34,67, and 134 kg N/ ha. Fertilizer N applied at 134 kg/ha increased total forage yield from 11 to 459/0 compared to 34 kg N/ha. ‘Lincoln’ smooth bromegrass (Bromus inermus Leyss.) and wheatgrass sp. yields were increased 30 and 3796, respectively, in 1981 while botanical composition on a percent by weight basis increased 15 and 19%, respectively. Compared to the 34 kg N/ha rate, yield and percent composition of ‘Vernal‘ alfalfa (Medicago sativa( L.) were decreased by the 134 kg N/ha rate. Total forage yields were not increased by fertilizer P. Yield and percent composition of wheatgrass increased with increasing additions of P, while the percent composition of smooth bromegrass decreased. Yields of smooth bromegrass and wheatgrass were highly correlated with the cumulative P applied 4 to 6 years prior to the 1981 harvest. Fertilizer recommendations based on soil test values accurately predicted response to N and P fertilizer.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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