Analysis of a 12-Year Corn-Small Grain Rotation Experiment at Four Fertility Levels
1977
Harner, E James | Pohlman, G. G. | Sperow, C. B.
Seven 2-year rotations were laid out in 1953 in order to determine the long term effects of fertilizer rate on the yields of corn-small grain cropping systems on Wheeling fine sandy loam soil (ultic hapludalf). It was also desired to examine the effects of rotation and fertilizer rate on total digestible nutrient (TDN) production and soil nutrient content. Previously, little information of this nature was available. The rotations were corn (Zea mays L.), wheat (Triticum aestivum L.), corn-winter barley (Hordeum vulgate L.), corn-winter oats (Avena sativa L.), corn-rye (Secale cereale L.), corn-spring oats, corn silage-winter barley, and corn silage-winter oats. Fertilizer applications of 336 kg/ha, 672 kg/ha, 1,008 kg/ha, and 1,344 kg/ha of 5-10-10 fertilizer were applied annually. The randomization and placement of crops and fertilizer was basically a split block with repeated measurements over time. Orthogonal contrasts were examined for the fertilizer, cycle, and rotation terms. The analysis was done in three parts: 1) for yields of each crop in each rotation; 2) for total digestible nutrients; and 3) for soil nutrients. The conclusions of the statistical analysis are: 1) corn silage and most of the small grains had significant linear increases in yields with increasing levels of fertilization; 2) corn silage and some of the small grain crops had a significant linear fertilizer by cycle interaction; 3) TDN production, the gain of available soil P and K, and the loss of soil N were linearly related to fertilizer rates; and 4) TDN production was lowest for the corn grain-oats rotations and highest for the corn silage rotations.
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