Yields and Protein Contents of Crops in Various Rotations1
- J. A. Hobbs2
In 1956 a study was initiated at Manhattan, Kansas, to measure effects on crop yield and protein content of five crop rotations: continuous wheat; continuous grain sorghum, sorghum, wheat, wheat; alfalfa, (2 years), sorghum, wheat, wheat; and bromegrass (2 years), sorghum, wheat, wheat. The study had a split plot, randomized block design with four replications. Three levels of nitrogen fertilizer were superimposed over the rotation variables.
Cereal crop yields were not improved by including other cereals or perennial crops in a rotation on a Geary silty clay loam, upland soil. From 1959 through 1967 average wheat yields were highest in the continuous wheat system; sorghum yields were best in the sorghum, wheat, wheat rotation, and in the continuous sorghum system. More often than not sorghum yields were reduced following the perennial crops, due no doubt to moisture deficiency.
Nitrogen fertilizer, which increased wheat yields in some years and decreased them in others, had little effect on the 9-year average wheat yields. Nitrogen fertilizer generally increased sorghum yields.
Protein content of cereal grain was highest in the alfalfa rotation and was increased by applying nitrogen fertilizer.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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