Influence of Nitrogen, Phosphorus, and Plant Population on Yield and Quality of Forage Corn
1972
Robinson, D. L. | Murphy, L. S.
The acreage of forage corn (Zea mays L.) produced in Kansas has steadily increased to meet the demand for corn silage required by commercial feedlots, Fertilization practices and plant populations are major factors involved in corn production, but their combined effects on yield and quality of forage have not been thoroughly evaluated. Therefore, irrigated forage corn was grown at five plant populations and five levels each of N and P at five field locations in central Kansas during a 3-year period to determine the influence of each variable on yield and quality of forage produced. An incomplete factorial arrangement of 23 treatments was used in a randomized complete block design. Multiple regression analyses indicated both forage and grain yields were significantly affected by N but not by P or plant population treatments. Treatment variables contributed little to variability in forage quality as measured by in vitro fermentation and forage fiber analyses. Nitrogen, cellulose, and lignin concentrations in the forage contributed up to 84% of the variation in in vitro dry matter digestibility (IVDMD). Simple correlation coefficients indicated a significant negative relationship between N and cellulose concentrations, a significant positive relationship between cellulose and lignin concentrations, and no consistent relationship between lignin and N concentrations in the forage. These results indicate that in central Kansas, irrigated corn yields are primarily a function of the rate of N application, and that a rather wide range of plant populations can be tolerated without significantly affecting yield or quality of forage produced.
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