Nitrogen Conservation under Corn Planted in Quackgrass Sod
1975
Bennett, O. L. | Stanford, G. | Mathias, E. L. | Lundberg, P. E.
The mechanics of growing corn (Zea mays L.) in a grass sod using the no-tillage concept have recently been developed. However, little is known abouthe fate of fertilizers, especially nitrogen, or the potential uses of such plant species as quackgrass (Agropyron repens L.) in this management system. Silage yields of corn were determined from field studies in which corn sod-planted in quackgrass, treated with six rates of atrazine, was compared to conventionally planted corn. The effects of no tillage and conventional tillage, using two rates of atrazine on total soil N, and N mineralization potential were compared. Yields of corn silage produced in herbicide-treated quackgrass were significantly higher than yields from conventional tillage. In the first year, silage yields increased with rates of atrazine. Quackgrass persisted for a 2-year period at the three lowest rates of atrazine but not at higher rates. After the first season, mineral N (largely NO₃-N) was significantly greater under untilled quackgrass than under plowed plots, However, by the following spring differences associated with tillage method had disappeared. Soil N mineralization potential, NO, and total N in the 0- to 15-cm layer were considerably higher for untilled than for plowed soils. However, in untilled plots, these values were unaffected by rate of atrazine.
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