Soil physical degradation is a current problem in Molisols of the Pampas Region under no-tillage (NT), that has been related to over-simplified agricultural systems with scarce or no rotations and long winter bare fallows. Soil physical quality (SPQ) is a key factor of soil health and productivity, as it controls root development and air and water fluxes and storage in the soil, which in turn affect nutrient uptake and plant growth. Cover crops have been proposed as a companion agricultural practice to improve NT performance and SPQ. The aim of this study was to evaluate the effect of the inclusion of winter cover crops in different cropping sequences on capacity and intensity indicators of SPQ in two soils of different texture under NT and to compare it with different traditional crop sequences, including non-agricultural plots. SPQ was evaluated at two different sites, one with a silty loam Argiudoll and the other with a sandy loam Hapludoll. Treatments included plots with and without cover crops, with different summer crop sequences (continuous soybean and corn – soybean rotations). Also, a corn – wheat/soybean rotation with and without pastures was evaluated. All treatments had more than 15 years under the same management. We measured soil organic carbon (SOC), and capacity SPQ indicators (bulk density, total porosity, pore size distribution, air capacity, plant available water, relative field capacity and S index). We also measured dynamic SPQ indicators derived from field infiltration tests (saturated and near saturation hydraulic conductivity, effective macro and mesoporosity, and porosity connectivity indexes for different pore families). On the silty loam Argiudoll, cover crops increased SOC but failed to improve SPQ. This was related to soil physical degradation and the low ability of these soils for structure regeneration. On the sandy loam Hapludoll, cover crops had mixed effects on SOC and pore size distribution, but increased near saturation hydraulic conductivity, in the case of the corn – soybean rotation with cover crops, reaching values similar to those of a natural grassland.

土壤物理退化是潘帕斯地区免耕 (NT) 下 Molisols 的当前问题，这与过度简化的农业系统有关，很少或没有轮作以及长期的冬季裸休。土壤物理质量 (SPQ) 是土壤健康和生产力的关键因素，因为它控制根系发育以及土壤中空气和水的通量和储存，进而影响养分吸收和植物生长。覆盖作物已被提议作为改善 NT 性能和 SPQ 的配套农业实践。本研究的目的是评估在不同种植序列中加入冬季覆盖作物对 NT 下两种不同质地土壤中 SPQ 容量和强度指标的影响，并将其与不同的传统作物序列，包括非农业作物序列进行比较。地块。在两个不同地点对 SPQ 进行了评估，一个地点是粉质壤土 Argiudoll，另一个地点是砂质壤土 Hapludoll。处理包括有和没有覆盖作物的地块，具有不同的夏季作物序列（连续大豆和玉米 - 大豆轮作）。此外，还评估了有和没有牧场的玉米-小麦/大豆轮作。所有治疗均在同一管理下超过15年。我们测量了土壤有机碳 (SOC) 和容量 SPQ 指标（容重、总孔隙度、孔径分布、空气容量、植物可用水、相对田间持水量和 S 指数）。我们还测量了来自现场渗透测试的动态 SPQ 指标（饱和和接近饱和的导水率、有效宏观和中孔隙度以及不同孔隙系列的孔隙度连通性指数）。在粉质壤土 Argiudoll 上，覆盖作物增加了 SOC，但未能提高 SPQ。这与土壤物理退化和这些土壤的结构再生能力低有关。在沙质壤土 Hapludoll 上，覆盖作物对 SOC 和孔径分布有不同的影响，但在玉米 - 大豆与覆盖作物轮作的情况下增加了接近饱和的导水率，达到与天然草地相似的值。