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Intensive cropping of maize in the southeastern United States

Busscher, W.J., Sojka, R.E.
Soil technology 1994 v.7 no.3 pp. 197
Zea mays, Helianthus annuus, Glycine max, Trifolium incarnatum, double cropping, intensive cropping, continuous cropping, seedbed preparation, tillage, minimum tillage, discing, no-tillage, weed control, cultural control, chemical control, crop management, irrigated conditions, dry environmental conditions, soil water content, soil profiles, crop yield, nutrient content, chemical constituents of plants, reduced tillage, conventional tillage, South Carolina
The long growing season of the southeastern Coastal Plains allows planting of a second crop after spring-planted maize (Zea mays L.). Second crops have been shown to reduce erosion and prevent leaching of nutrients and pesticides. Maize grown with a second annual crop might also have a yield advantage over mono-cultured maize. Seven tillage/cropping systems were compared. They included disking for weed control, disking for seedbed preparation, or no disking. Double-cropped treatments included sunflower (Helianthus annuus L.), soybean (Glycine max. L.), a cover crop [crimson clover (Trifolium incarnatum L.)] or no double crop. Double-cropped soybean yields did not respond to irrigation. They averaged 0.63 Mg/ha over 4 years. This is less than half of the local non-double-cropped yields. Sunflower yields averaged 0.89 Mg/ha, also less than non-double-cropped yields (1.0-2.5 Mg/ha). The best continous maize yields (7-8 Mg/ha) were from treatments with disking in some phase of the operation. Treatments with lower maize yields generally had higher plant nutrient contents. Double-cropped maize yields significantly (P<0.10) outyielded mono-cropped maize yields in two of the three years. In 1984, a dry year, the minimum tillage treatment had lower tensiometer readings than the conventionally tilled treatment.