（通訊員 杜俊）近日，我校yl7703永利夏俊芳教授課題組研究成果以“Investigation of the burial and mixing performance of a rotary tiller using discrete element method”為題在Soil and Tillage Research發表。研究建立了粘性土壤的顆粒力學模型，揭示了旋埋刀輥對粘性土壤的擾動過程，為長江中下遊水旱輪作區稭稈還田機具作業性能優化提供了新思路。

長江中下遊水旱輪作區土壤粘性大，稭稈含量高，旋耕作業後土壤中存在稭稈堆積現象，旋耕作業時刀具對土壤的擾動決定了耕後稭稈的分布特性。然而，稭稈還田作業過程中土壤-刀具相互作用複雜，傳統方法難以揭示刀具對土壤的擾動過程，制約了土壤翻埋機理解析和旋耕刀具性能優化。因此，闡釋土壤-刀具相互作用下的土壤擾動過程尤為重要。

該研究基于離散元法建立粘性土壤顆粒力學模型，針對粘性土壤離散元法建模過程中輸入參數及接觸模型難以确定的問題，本研究基于土槽試驗對粘性土壤顆粒輸入參數的敏感性進行分析，對最敏感參數進行單一标定；對比不同粘性接觸模型仿真效果，建立了粘性土壤的離散元法模型；通過提取不同深度土壤顆粒微觀遷移特性，研究了旋耕刀和螺旋橫刀對土壤的擾動形式、範圍及強度，獲取了刀具不同工作參數及結構參數下的土壤擾動過程，分析了刀具擾動特性的影響因素。研究表明，HM-JKR模型（Hertz-Mindlin contact model with JKR）對粘性土壤的模拟更符合旋耕作業時的土壤形态；作業參數方面，耕深對刀具擾動特性影響最顯著，當耕深由150mm增加到180mm時，旋耕刀和螺旋橫刀對土壤的平均擾動強度分别提高25%和30%；結構參數方面，旋耕刀正切刃結構、旋耕刀數量及間距是優化旋埋刀輥擾動性能的關鍵。該研究為優化長江中下遊水旱輪作區稭稈還田機具作業性能提供了新思路。

yl7703永利杜俊老師為論文第一作者，夏俊芳教授為論文通訊作者。該研究得到國家自然科學基金、湖北省自然科學基金、公益性行業（農業）科研專項和國家重點研發計劃等項目的資助。

審核人：夏俊芳

【英文摘要】

Rotary tiller is a widely used tillage tool in China, and its burial and mixing ability determine its performance. Discrete element method (DEM) is a promising numerical method to study the soil-tool interaction, and a suitable contact model is required to obtain a reasonable accuracy. In order to investigate the burial and mixing performance of a rotary tiller consisted of rotary blade and spiral horizontal blade in silty clay loam, two cohesion contact models HM-B and HM-JKR were compared. The sensitivity analysis for HM-B and HM-JKR were conducted by Plackett-Burman test. The bonding stiffness of HM-B and the surface energy of HM-JKR were the most sensitive parameters for their contact model, respectively, and were calibrated to compare their simulation performance. HM-JKR obtained a relatively smaller error on torque compared with measurement results in a soil bin test. The tillage characteristics of rotary blade and spiral horizontal blade were studied, and the effect of working conditions and rotary tiller structures on these were investigated by simulation. The distribution ratio and the disturbance intensity were selected to evaluate the burial and mixing performance. Compared with rotary blade, the spiral horizontal blade obtained a larger disturbance area and intensity. Tillage depth had the most significant effect on the tillage characteristics. The average disturbance intensity of rotary blade and spiral horizontal blade increased nearly 25% and 30% with the increase of tillage depth from 150 mm to 180 mm. The L-bend structure of the rotary blade was important to the burial and mixing performance of rotary tiller. A reasonable number of rotary blade group in the rotary tiller and distance between each rotary blade group can obtain a satisfied burial and mixing performance with a relative low torque consumption.

論文鍊接：https://doi.org/10.1016/j.still.2022.105349