Spatial structural variations in ridge-furrow unit size and its ratio can result in the drastic fluctuation of soil hydrothermal status, and thereby affect water use and yield formation in dryland crops. Previous studies were little focused on the responses of dryland wheat productivity to the structural changes in ridge-furrow plastic mulching (RFM) system and its mechanism in semiarid eastern African Plateau (EAP). A two-year field experiment was conducted in Juja, a semiarid area in Kenya from 2015 to 2016. There were seven treatments of ridge-furrow width and ratios in randomized block design as follows: (1) 40 cm ridge width and 20 cm furrow width (R₄F₂, the same below), (2) R₃F₂, (3) R₂F₂, (4) R₃F₄, (5) R₂F₄, (6) R₃F₆ and (7) R₂F₆, and conventional flat planting without mulching as control (CK). The results showed that R₄F₂, R₃F₂, R₂F₂, R₃F₄ and R₂F₄ treatments significantly improved soil water storage and temperature across two growing seasons compared with CK (P < 0.05). Among all the treatments, R₃F₂ and R₂F₂ obviously achieved the highest plant height, leaf area, aboveground biomass (AgB), grain yield and water use efficiency (WUE) (P < 0.05). Also, R₂F₂ had the highest economic benefits in all treatments. The optimal ridge-furrow ratio appeared to be 1.32–1.38, 1.28–1.31, 1.39–1.49, 1.37–1.45 and 1.46–1.56 for wheat yield, AgB, WUE_Y, WUE_B and harvest index (HI), respectively. In addition, wheat yield, AgB, WUE and HI tended to decrease linearly with the increased ridge-furrow unit size. In conclusion, ridge-furrow ratio of 1–1.5 (R₂F₂ to R₃F₂) in combination with the minimum ridge-furrow unit size proved to be the optimum RFM system for the best dryland wheat productivity in accordance to regional soil and climate characteristics in semiarid EAP and other similar areas of the world.

垄沟单位面积及其比例的空间结构变化会导致土壤热液状态的剧烈波动，从而影响旱地作物的水分利用和产量形成。先前的研究很少集中在旱地小麦生产力对垄沟塑覆（RFM）系统结构变化的响应及其在半干旱东部非洲高原（EAP）的机理。2015年至2016年，在肯尼亚半干旱地区Juja进行了为期两年的田间试验。随机区组设计对垄沟宽度和比率进行了7种处理，具体方法如下：（1）垄宽40厘米，沟宽20厘米宽度（R ₄ F ₂，下同），（2）R ₃ F ₂，（3）R ₂ F ₂，（4）R ₃ F ₄，（5）R ₂ F ₄，（6）R ₃ F ₆和（7）R ₂ F ₆，以及不覆盖的常规平整作对照（CK）。结果表明，与CK相比，R ₄ F ₂，R ₃ F ₂，R ₂ F ₂，R ₃ F ₄和R ₂ F ₄处理显着改善了两个生长季节的土壤储水量和温度（P  <0.05）。在所有治疗方法中，R ₃ F₂和R ₂ F ₂明显达到最高的株高，叶面积，地上生物量（AgB），谷物产量和水分利用效率（WUE）（P  <0.05）。另外，在所有处理中，R ₂ F ₂具有最高的经济利益。小麦单产，AgB，WUE _Y，WUE _B和收获指数（HI）的最佳垄沟比分别为1.32–1.38、1.28–1.31、1.39–1.49、1.37–1.45和1.46–1.56 。另外，小麦产量，AgB，WUE和HI倾向于随着垄沟单位尺寸的增加而线性下降。总之，垄沟比为1–1.5（R ₂ F ₂与R ₃ F ₂）结合最小的垄沟单位尺寸，被证明是根据半干旱EAP和世界其他类似地区的区域土壤和气候特征，实现最佳旱地小麦生产力的最佳RFM系统。