In strip tillage (ST), tillage is limited to the crop rows while soil between the rows remains undisturbed. ST offers multiple potential benefits compared to full-width tillage (FWT), including preventing erosion and reducing the number of operations required for soil preparation. However, weed management may be complicated by the lack of soil disturbance in ST. We conducted field experiments and a partial budget analysis to study tradeoffs associated with ST within cabbage and sweet corn production.In order to understand and address weed management challenges associated with ST, field studies were evaluated the impacts on emergence, growth, and reproduction of Powell amaranth (Amaranthus powellii), a widespread problem weed in vegetable cropping systems. Weed emergence in cabbage was examined in ST and FWT, with and without a cover crop. We manipulated soil moisture and nitrogen, and planted fungicide-treated seeds to elucidate mechanisms that affect weed emergence. Emergence was often lower in ST compared to FWT, though this effect diminished over time. Cover crop residues also reduced early emergence of weeds but in some cases led to increased emergence later in the season. This suppression was often alleviated by fungicides, suggesting that fungal pathogens may mediate this cover crop effect. In another set of experiments, plots without cabbage were included to assess the relative importance of crop competition and soil moisture and nitrogen on weed growth and reproduction. ST was often associated with higher soil moisture while the oat cover crop also reduced soil nitrogen in many cases. Weed growth, however, was often influenced more by the cabbage than by soil moisture and nitrogen. Yield of weedy and weed-free cabbage was not affected by ST or the cover crop. To evaluate the economic impact of ST adoption in sweet corn, we conducted a partial budget analysis with various assumptions regarding prices, yield, and weed management costs to examine changes in profitability. Tillage-related costs were estimated using an economic engineering approach. Sweet corn yields with a small grain cover crop were similar in ST and FWT across nine site years of experiments suggesting that yields, and thus revenue, will be maintained with ST. ST adoption resulted in increased profits of $26-34/acre depending on the level of investment. To evaluate potential environmental impacts of ST, we compared the effects of FWT and ST with deep-banded N fertilizer on potentially leachable nitrate (PLN) and nitrous oxide flux (NOF) in a cabbage and sweet corn rotation. Two ST treatments varying the strip position from year to year were included. PLN after harvest was assessed using 1 m deep soil cores. Compared to FWT, ST had little effect on PLN in four of five crop-years. In 2012, following drought conditions with poor sweet corn growth, ST reduced PLN by 44-62 kg/ha compared to FWT. NOF in the cabbage field was lower in ST than in FWT. Relative strip placement had no effect on these losses, though sweet corn yield was 10-18% higher when strips were moved from year to year. ST can reduce production costs and weed emergence, and has the potential to reduce nitrogen loss while maintaining cabbage and sweet corn yields.
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