Abstract. Using laboratory measurements and numerical simulations, we studied the long-term impact of contrasting tillage and cover cropping systems on soil structure and soil hydraulic properties. Complete water retention and conductivity curves for top (0–5 cm) and subsurface (20–25 cm) samples were characterized and contrasted. Plot-level properties of water storage and retention were evaluated using numerical simulations in HYDRUS-2D software. Soils under no-till (NT) and cover cropping (CC) systems showed an improved soil structure in terms of pore size distribution (PSD) and the hydraulic conductivity (K) under these systems led to increased infiltration rate and water retention. The conventional measurement of water content at field capacity (water content at −33 kPa suction) and the associated plant available water (PAW) showed that NT and CC plots had lower water content at field capacity and lower PAW compared to standard-till (ST) and plots without cover crop (NO). The numerical simulations, however, showed that NT and CC plots have higher profile-level water storage (albeit marginal in magnitude) and water availability following irrigation. Because the numerical simulations consider retention and conductivity functions simultaneously and dynamically through time, they allow the capture of hydraulic properties that are arguably more relevant to crops. The changes in PSD, water conductivity, and water storage associated with NT and CC systems observed in this study suggest that these systems are beneficial to general soil health and improve water retention at the plot scale.

中文翻译：

---

覆盖作物和减扰耕作对土壤孔隙大小和土壤储水量的长期影响

摘要。使用实验室测量和数值模拟，我们研究了对比耕作和覆盖种植系统对土壤结构和土壤水力特性的长期影响。对顶部 (0–5 cm) 和地下 (20–25 cm) 样品的完整保水率和电导率曲线进行表征和对比。使用 HYDRUS-2D 软件中的数值模拟评估了地块级别的储水和保水特性。免耕 (NT) 和覆盖作物 (CC) 系统下的土壤在孔径分布 (PSD) 和导水率 (K) 方面显示出改善的土壤结构，导致入渗率和保水率增加。田间持水含水量（-33 kPa 吸力下的含水量）和相关植物有效水 (PAW) 的常规测量表明，与标准耕作 (ST) 相比，NT 和 CC 地块的田间持水含水量和 PAW 较低) 和没有覆盖作物的地块 (NO)。然而，数值模拟表明，NT 和 CC 地块在灌溉后具有更高的剖面蓄水量（尽管幅度不大）和可用水量。由于数值模拟同时并随着时间的推移动态地考虑保留和传导率函数，它们允许捕获可以说与作物更相关的水力特性。PSD、水电导率的变化，