Yield contribution of nitrogen fertilizer, herbicide, and insecticide in a corn-soybean rotation
1995
Hons, F.M. | Saladino, V.A.
Interest is increasing in alternative, reduced input cropping systems. Potential interactive effects of input additions or eliminations on crop yield must be delineated to develop the most resource-efficient cropping systems. Information of this type is especially lacking in the southern United States. The principal objective of this field study was to determine the main and interactive effects of nitrogen (N) fertilization herbicide, and insecticide on grain yields in a corn (Zea mays L.) - soybean [(Glycine max (L.) Merr.)] rotation. Dryland studies were conducted for four years (1990-1993) on a Weswood silt loam soil (fine, mixed, thermic Fluventic Ustochrept). Variables included none or "optimal" applications of N fertilizer, herbicide, and insecticide. Mean corn grain yield was increased 156% by N fertilization compared to the no N control. Herbicide significantly increased corn grain yield two of four years, while soil-applied insecticide had no effect. Johnsongrass [Sorghum halepense (L.) Pers.] was identified as the primary competitive weed species in corn. No interactions of inputs were observed for corn grain yield. Nitrogen fertilization and herbicide did not affect soybean yield, but insecticide increased average soybean yield by 29%. Interactions of N fertilization and insecticide and herbicide and insecticide were significant for soybean yield.
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