Design and Plowing Performance of an In Situ Soil-Turning Plow for Facility Agriculture

To address soil degradation and pest accumulation in facility agriculture, this study developed an in situ soil-turning plow for deep soil inversion under spatially constrained greenhouse conditions. A reference plow surface was obtained by reverse engineering, and the final in situ plow surface was reconstructed using plow-body forming theory and a constrained soil-turning trajectory. Soil contact parameters were calibrated in EDEM using the measured soil moisture content and angle of repose. An in situ furrow soil retention rate was proposed to evaluate the proportion of disturbed soil remaining within or returning to the original furrow region. Plackett–Burman screening identified plowing width, plow-body installation angle, and soil-cutting angle as the main factors affecting the retention rate. Box–Behnken optimization yielded optimal values of 278.392 mm, 40.522°, and 23.211°, respectively, with a predicted retention rate of 81.166%. Physical validation showed a 3.13% relative error between predicted and measured values. The optimized plow provides a design reference for compact deep-tillage machinery in greenhouses where lateral soil displacement must be minimized.