Organic grain producers are interested in reducing tillage to conserve soil and decrease labor and fuel costs. We examined agronomic and economic tradeoffs associated with alternative strategies for reducing tillage frequency and intensity in a cover crop–soybean (Glycine max L. Merr.) sequence within a corn (Zea mays L.)–soybean–spelt (Triticum spelta L.) organic cropping system experiment in Pennsylvania. Tillage-based soybean production preceded by a cover crop mixture of annual ryegrass (Lolium perenne L. ssp. multiflorum), orchardgrass (Dactylis glomerata L.) and forage radish (Raphanus sativus L.) interseeded into corn grain (Z. mays L.) was compared with reduced-tillage soybean production preceded by roller-crimped cereal rye (Secale cereale L.) that was sown after corn silage. Total aboveground weed biomass did not differ between soybean production strategies. Each strategy, however, was characterized by high inter-annual variability in weed abundance. Tillage-based soybean production marginally increased grain yield by 0.28 Mg ha−1 compared with reduced-tillage soybean. A path model of soybean yield indicated that soybean stand establishment and weed biomass were primary drivers of yield, but soybean production strategy had a measurable effect on yields due to factors other than within-season weed–crop competition. Cumulative tillage frequency and intensity were quantified for each cover crop—sequence using the Soil Tillage Intensity Rating (STIR) index. The reduced-tillage soybean sequence resulted in 50% less soil disturbance compared to tillage-based soybean sequence across study years. Finally, enterprise budget comparisons showed that the reduced-tillage soybean sequence resulted in lower input costs than the tillage-based soybean sequence but was approximately $114 ha−1 less profitable because of lower average yields.

中文翻译：

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替代覆盖作物和有机大豆序列之间的农艺和经济权衡

有机谷物生产商有兴趣减少耕作以保护土壤并降低劳动力和燃料成本。我们研究了与减少覆盖作物——大豆的耕作频率和强度的替代策略相关的农艺和经济权衡。最大甘氨酸L. Merr.) 玉米中的序列 (玉米L.)–大豆–拼写 (小麦L.) 宾夕法尼亚州的有机种植系统实验。以耕作为基础的大豆生产之前是一年生黑麦草的覆盖作物混合物（Lolium perenne L. ssp. 何首乌), 果园草 (肾小球藻L.) 和草料萝卜 (萝卜L.) 种入玉米粒中 (Z.梅斯L.) 与减耕大豆生产进行了比较，然后是碾压谷物黑麦 (黑麦L.) 在玉米青贮饲料之后播种。大豆生产策略之间的总地上杂草生物量没有差异。然而，每种策略的特点是杂草丰度的年际变化很大。以耕作为基础的大豆生产略微增加了 0.28 毫克/公顷的谷物产量-1与减耕大豆相比。大豆产量的路径模型表明，大豆林分建立和杂草生物量是产量的主要驱动因素，但由于季节内杂草-作物竞争以外的因素，大豆生产策略对产量有可测量的影响。使用土壤耕作强度等级 (STIR) 指数对每种覆盖作物的累积耕作频率和强度进行量化。在整个研究年份，与基于耕作的大豆序列相比，减少耕作的大豆序列导致土壤干扰减少 50%。最后，企业预算比较表明，减少耕作的大豆序列比基于耕作的大豆序列的投入成本更低，但约为 114 公顷-1由于平均收益率较低，因此利润较低。