Long-term tillage and crop management studies are useful for determining crop production practices that are conducive to securing sustainable yields and profits. The overall goal of this study was to evaluate the effects of 17-year, long-term crop rotations involving cotton, corn, and soybean on yield and profitability. The study was established in 2004 at the Delta Research and Extension Center, Stoneville, Mississippi with six crop rotations. The crop rotations were continuous cotton (CT), corn-cotton (CR-CT), corn-cotton-cotton (CR-CT-CT), corn-soybean (CR-SB), soybean-corn-cotton (SB-CR-CT), and soybean-corn-cotton-cotton (SB-CR-CT-CT) with every crop in a rotation planted yearly. Thirty years of historical (1974–2003) and 17 years (2004–2020) of precipitation data during the 2nd (Q-2: 21 March to 21 June) and 3rd quarters (Q-3: 22 June to 22 September) were used to identify dry, normal, and wet precipitation quarter weather classifications (WC). Both seed cotton and lint yields were greatest in the wet-dry WC and least in the dry-wet WC under all the crop rotations. The normal-normal WC resulted in highest corn grain yields under all rotations, whereas dry-dry resulted in lowest grain yield. Soybean yield was highest under the dry-wet WC for each crop rotation including CR-SB, SB-CR-CT, and SB-CR-CT-CT. The most profitable rotation was CR-CT-CT followed by CR-CT with annual expected profit of $1042 ha⁻¹ and $1024 ha⁻¹, respectively. The CR-SB rotation was the least profitable rotation in the study.

长期耕作和作物管理研究有助于确定有利于确保可持续产量和利润的作物生产实践。本研究的总体目标是评估涉及棉花、玉米和大豆的 17 年长期作物轮作对产量和盈利能力的影响。该研究于 2004 年在密西西比州斯通维尔的三角洲研究和推广中心建立，有六种作物轮作。作物轮作连续棉花（CT），玉米 - 棉花（CR-CT），玉米 - 棉花 - 棉花（CR-CT-CT），玉米 - 大豆（CR-SB），大豆 - 玉米 - 棉花（SB-CR） -CT）和大豆-玉米-棉花-棉花（SB-CR-CT-CT），每种作物每年轮作种植。第二季度（Q-2：3 月 21 日至 6 月 21 日）和第三季度（Q-3：6 月 22 日至 9 月 22 日）用于识别干燥、正常和湿润降水季度天气分类 (WC)。在所有农作物旋转下，在干燥的WC中，种子棉和棉绒的产量均为最大，在干湿WC中均最大。正常-正常 WC 在所有轮作下导致最高的玉米籽粒产量，而干-干导致最低的籽粒产量。对于包括 CR-SB、SB-CR-CT 和 SB-CR-CT-CT 在内的每种作物轮作，干湿湿润条件下的大豆产量最高。利润最高的轮作是 CR-CT-CT，其次是 CR-CT，年预期利润为 1042 美元公顷 正常-正常 WC 在所有轮作下导致最高的玉米籽粒产量，而干-干导致最低的籽粒产量。对于包括 CR-SB、SB-CR-CT 和 SB-CR-CT-CT 在内的每种作物轮作，干湿湿润条件下的大豆产量最高。利润最高的轮作是 CR-CT-CT，其次是 CR-CT，年预期利润为 1042 美元公顷 正常-正常 WC 在所有轮作下导致最高的玉米籽粒产量，而干-干导致最低的籽粒产量。对于包括 CR-SB、SB-CR-CT 和 SB-CR-CT-CT 在内的每种作物轮作，干湿湿润条件下的大豆产量最高。利润最高的轮作是 CR-CT-CT，其次是 CR-CT，年预期利润为 1042 美元公顷^分别为-1和 $1024 ha ^-1。CR-SB 轮换是研究中利润最低的轮换。