Crop rotations can reduce problems that occur in monoculture planting systems. In 1990, at Lane, Okla., 0.5 ha of Bernow fine-loamy soil was planted to peanut (Arachis hypogaea L.). In the following 5 years, bell pepper (Capsicum annuum var. annuum L.), cucumber (Cucumis sativas L.), navy bean (Phaseolus vulgaris L.), and cabbage (Brassica oleracea L. Capitata group) were planted in one of four rotations after 1, 2, or 3 years of peanut. The first vegetable planting in each annual rotation was followed by either vegetables or peanut in following years. In 3 of the 6 years, peanut or vegetables were planted in each rotation. Peanut yields in the first year averaged 6.6 Mg·ha-1, but were <1.9 Mg·ha-1 thereafter. Yields of the first vegetable planting, which followed 1 or 2 years of peanut, were normal for this location, but were significantly lower after 3 years of peanut. For second or third plantings of vegetables in rotations, yields were reduced up to 50% compared to the first vegetable planting. For most crops, the rotation that had 3 years of peanut followed by 3 years of vegetables generally produced the least cumulative yield. Numbers of sclerotia produced by soilborne plant pathogenic fungi fluctuated over the years, but were the same in the spring of the second and sixth years. Rotating these crops appears to have limited applicability for maintaining high vegetable or peanut yields.
Vincent M. Russo
Abiotic and biotic factors, and government farm policy, affect peanut (Arachis hypogaea L.) production especially in the Southern Plains of the United States. A coincident increase in vegetable production has led to interest in diversification of production on land that has historically supported peanut. A multi-year experiment was conducted from 1998 to 2001 to determine how rotating bell pepper (Capsicum annuum var. annuum L.) and sweet corn (Zea mays L.) with peanut affect yields of all three crops. In the first year, the site was planted to peanut, except for those areas of the field that would have monocultured bell pepper or sweet corn throughout the experiment. In following years, parts of the field that were planted with peanut were planted with either peanut, bell pepper, or sweet corn. Except for the monocultured crops, plots had 2 years of peanut and one year each of bell pepper or sweet corn in one of four rotations. Yields were determined and terminal market value was assigned to crops. Cumulative yields for monocultured bell pepper and sweet corn were 27.8 and 22.8 Mg·ha-1 after 4 years. The best yield of bell pepper or sweet corn in any rotation was 15.3 or 11.3 Mg·ha-1, respectively. Rotation did not affect peanuts, and cumulative yields for monocultured peanut were 8.39 Mg·ha-1 and averaged 2.13 Mg·ha-1 per year in rotations. Cumulative yields for all crops in rotations where vegetables were planted in the last 2 years averaged 21.5 Mg·ha-1 as opposed to 13.8 Mg·ha-1 when vegetables were planted in the middle 2 years of a 4-year rotation. Yields of all crops were modified by environmental conditions, and terminal market price affected crop value so that high yields were not always associated with high returns.