Diversified cropping systems integrated with winter cover crops (CCs) and no-till (NT) systems can provide substantial soil conservation benefits in the midwestern Corn Belt of the United States, but there is uncertainty on how these practices affect producer profits. This study compared crop yield and economic performance from cropping systems that featured three crop rotations: corn ( Zea mays L.)–soybean ( Glycine max [L.] Merr.; two-year), corn–soybean–oat ( Avena sativa L.; three-year), and corn–soybean–oat–winter wheat ( Triticum aestivum L.; four-year); two tillage systems: NT and conventional-till (CT); and two cover cropping managements: CC and no-cover crop. Tillage and rotation treatments were established in 1991 whereas cover cropping was introduced in 2013, so data from 2014 through 2018 were used for the yield and economic comparisons. Over the study period, the NT system reduced the corn yield across all rotations but increased the soybean yield under two-year rotation as compared to the CT system. Hence, both tillage systems were economically equivalent, whereby the NT system improved benefit-cost ratio as compared to the CT system. In our study, while CC in its short term did not contribute to yield and overall economic benefits, we observed highest gross revenue and second-best net returns from two-year CC plots under the NT system as compared to all other cropping systems. When compared to two-year rotations, diverse crop rotations (three- and four-year) increased the corn and soybean yields and associated profits yet compromised overall profitability due to the lower profits of small grains. It is important to identify other profitable crops that are beneficial for soils and the environment to diversify the corn–soybean rotations.

中文翻译：

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涉及不同轮作、耕作和覆盖作物的种植系统的作物产量和经济性

与冬季覆盖作物 (CC) 和免耕 (NT) 系统相结合的多样化种植系统可以为美国中西部玉米带提供大量的土壤保护效益，但这些做法如何影响生产者利润尚不确定。本研究比较了以三种轮作为特征的种植系统的作物产量和经济表现：玉米（Zea mays L.）-大豆（Glycine max [L.] Merr.；两年）、玉米-大豆-燕麦（Avena sativa L. .；三年），以及玉米-大豆-燕麦-冬小麦（Triticum aestivum L.；四年）；两种耕作系统：NT 和常规耕作 (CT)；和两种覆盖作物管理：CC 和无覆盖作物。耕作和轮作处理是在 1991 年建立的，而覆盖作物是在 2013 年引入的，因此，2014 年至 2018 年的数据用于产量和经济比较。在研究期间，与 CT 系统相比，NT 系统降低了所有轮作的玉米产量，但增加了两年轮作下的大豆产量。因此，两种耕作系统在经济上是等效的，因此与 CT 系统相比，NT 系统提高了效益成本比。在我们的研究中，虽然 CC 在短期内对产量和整体经济效益没有贡献，但与所有其他种植系统相比，我们观察到 NT 系统下两年 CC 地块的最高总收入和第二好的净回报。与两年轮作相比，不同的作物轮作（三年和四年）增加了玉米和大豆的产量和相关利润，但由于小谷物的利润较低，因此损害了整体盈利能力。