Conservation tillage offers an alternative approach for managing clayey soils in the midsouthern United States. This study compared conservation tillage seedbed preparation vs. conventional tillage main plots with subplots of (i) nonirrigated soybean (Glycine max L. Merr.), (ii) irrigated soybean, (iii) irrigated grain sorghum (Sorghum vulgare L.), (iv) irrigated soybean followed by irrigated grain sorghum, (v) irrigated soybean followed by irrigated corn (Zea mays L.), and (vi) continuous irrigated cotton (Gossypium hirsutum L.) for the years 1986 to 1991 at Keiser, AR. Cropping practices were similar to those used by producers in the area. Grain sorghum yielded better in a soybean rotation than in monoculture and also in conventionally tilled seedbed than in conservation tillage. For other crops, yield did not differ significantly by tillage. Except for cotton, conventional tillage resulted in higher average net returns (NR) than conservation tillage. Although the most profitable system was continuous cotton with conservation tillage, NR varied widely across years, and there were fewer observations for cotton than for other systems in the study. Among conventional tillage seedbed preparation, nonirrigated continuous soybean was more profitable than any of the irrigated systems, including irrigated soybean. However, irrigated soybean resulted in NR that were less variable than nonirrigated soybean. The study confirmed the increased variable costs and decreased equipment costs that accompany conservation tillage systems. Even with the dramatic changes in burndown herbicide costs that have occurred since the study was conducted, the rankings of the cropping systems for profitability would not change.
Construction in urban areas usually results in compacted soil, which restricts plant growth and infiltration. Nutrients may be lost in storm runoff water and sediment. The purpose of this study was to determine if existing lawns benefit from aeration and surface compost additions without the negative impact of nutrient loss in runoff. Four sets of lawns were compared, with or without compost plus aeration, as a paired comparison. Surface bulk density was significantly reduced in the treated lawns (1.32 versus 1.42 Mg·m −3 ). Visual evaluation of soil structure showed improvement in the treated lawns. Of fifteen measurement dates over four years, four dates showed significantly higher surface soil water contents in the treated lawns compared with the untreated lawns. When compared over time, three of the four treated lawns had significantly higher soil water content than the untreated lawns. Nutrient concentrations in rainfall simulator runoff were not significantly different between treated and control lawns, which showed that compost did not negatively impact water quality. Compost and aeration helped restore soil quality for urban soils of recent construction.
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