Department of Soil & Environment, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden.
Department of Agroecology & Environment, Agroscope, 8046 Zürich, Switzerland.
Proc Natl Acad Sci U S A. 2022 May 24;119(21):e2117699119. doi: 10.1073/pnas.2117699119. Epub 2022 May 16.
Mechanization has greatly contributed to the success of modern agriculture, with vastly expanded food production capabilities achieved by the higher capacity of farm machinery. However, the increase in capacity has been accompanied by higher vehicle weights that increase risks of subsoil compaction. We show here that while surface contact stresses remained nearly constant over the course of modern mechanization, subsoil stresses have propagated into deeper soil layers and now exceed safe mechanical limits for soil ecological functioning. We developed a global map for delineating subsoil compaction susceptibility based on estimates of mechanization level, mean tractor size, soil texture, and climatic conditions. The alarming trend of chronic subsoil compaction risk over 20% of arable land, with potential loss of productivity, calls for a more stringent design of farm machinery that considers intrinsic subsoil mechanical limits. As the total weight of modern harvesters is now approaching that of the largest animals that walked Earth, the sauropods, a paradox emerges of potential prehistoric subsoil compaction. We hypothesize that unconstrained roaming of sauropods would have had similar adverse effects on land productivity as modern farm vehicles, suggesting that ecological strategies for reducing subsoil compaction, including fixed foraging trails, must have guided these prehistoric giants.
机械化极大地促进了现代农业的成功，农业机械的更高产能实现了粮食产量的大幅增长。然而，产能的增加伴随着更高的车辆重量，这增加了土壤板结的风险。我们在这里表明，虽然在现代机械化的过程中，表面接触压力基本保持不变，但底土压力已经传播到更深的土壤层，现在超过了土壤生态功能的安全机械极限。我们开发了一种全球底土压实敏感性图，该图基于机械化水平、拖拉机平均尺寸、土壤质地和气候条件的估计值进行划分。超过 20%可耕地面临慢性底土压实风险的惊人趋势，可能导致生产力损失，这需要更严格的农机设计，考虑到内在的底土机械极限。由于现代收割机的总重量现在接近在地球上行走的最大动物——蜥脚类恐龙的重量，史前底土压实的悖论出现了。我们假设蜥脚类恐龙不受限制的漫游会对土地生产力产生与现代农用车辆类似的不利影响，这表明减少底土压实的生态策略，包括固定觅食路径，必须指导这些史前巨兽。
