Data from: Continuous corn and corn–soybean profits over a 45-year tillage and fertilizer experiment

Studies comparing profitability of tillage systems often examine narrow historic windows or exclude annual price fluctuations. This study uses a continuous corn (Zea mays L.) (CC; 1970–1990) and corn–soybean [Glycine max (L.) Merr.] (CS; 1991–2014) Tillage × Fertilizer study in somewhat poorly drained soils in southern Illinois to reconstruct partial annual budgets with historical prices for crops, fertilizers, lime, herbicides, fuel, labor, and machinery. Combinations of tillage (moldboard plow [MP], chisel tillage [ChT], alternate tillage [AT], and no-till [NT]) and fertilizer (Control, N-only, N+NPK starter, NPK+NPK starter, and NPK broadcast) treatments were evaluated. The CC profits were highest in NPK-applied treatments followed by N-only and Control. The MP treatments were similar to ChT and more profitable than NT, while AT fell between. In CS, NPK-applied treatments were similar regardless of tillage. Combined costs for herbicide, machinery, labor, and diesel were higher in MP and ChT systems than AT and lowest in NT, but were a small percentage of total costs (26.6, 26.0, 21.5, and 18.2%, respectively). Nitrogen fertilizer offered a return on investment of 396% in CC and 133% in CS while P & K returned 78% in CC and 109% in CS. Sensitivity analysis in CS showed that NT would be less profitable than MP if herbicide costs increased 850%. A 300% machinery cost increase would have made MP less profitable than NT. These findings suggest that since 1991 CS under NT carried the same potential for profit as other tillage systems under full fertility management.

现有针对耕作系统盈利能力的比较研究，往往仅考察狭窄的历史时间窗口，或忽略了年度价格波动因素。本研究依托一项于伊利诺伊州南部排水性能偏弱土壤中开展的耕作×施肥（Tillage × Fertilizer）定位试验，分别针对连作玉米（Zea mays L.，CC；1970–1990年）与玉米-大豆轮作（Glycine max (L.) Merr.，CS；1991–2014年）两种种植模式，利用历史价格数据重建了涵盖作物、肥料、石灰、除草剂、燃料、劳动力及农机具的年度部分预算。本研究对耕作措施（铧式犁耕[MP]、凿式松土[ChT]、间隔耕作[AT]与免耕[NT]）与施肥措施（不施肥对照、仅施氮肥、氮肥+NPK种肥、NPK基肥+NPK种肥以及撒施NPK）的组合处理进行了评估。连作玉米模式下，施NPK处理的收益最高，其次为仅施氮肥处理与不施肥对照。铧式犁耕处理的收益与凿式松土处理相近，且高于免耕处理，间隔耕作处理的收益则介于二者之间。玉米-大豆轮作模式下，无论采用何种耕作措施，施NPK处理的收益均无显著差异。除草剂、农机具、劳动力与柴油的总成本在铧式犁耕与凿式松土系统中高于间隔耕作系统，在免耕系统中最低；但该类成本占总成本的比例较低，分别为26.6%、26.0%、21.5%与18.2%。氮肥在连作玉米模式下的投资回报率为396%，在玉米-大豆轮作模式下为133%；而磷钾肥在连作玉米模式下的投资回报率为78%，在玉米-大豆轮作模式下为109%。玉米-大豆轮作模式下的敏感性分析结果显示：若除草剂成本上涨850%，免耕系统的收益将低于铧式犁耕系统；若农机具成本上涨300%，铧式犁耕系统的收益将低于免耕系统。本研究结果表明，自1991年起，玉米-大豆轮作模式下采用免耕措施时，其收益潜力与全量施肥管理下的其他耕作系统相当。