Improved yield by harvesting water with ridges and subgrooves using buried and surface plastic mulchs in a semiarid area of China

•Ridge-subgroove with plastic film mulching was applied in a dryland system.•Subgrooves with plastic film mulching increased topsoil temperature.•Subgroove with plastic film mulching increased large and moderate-sized potato yield.•Ridge-subgroove with plastic film mulching increased crop yields.

This paper determines the responses of soil temperature, water status and crop yields to a new planting pattern involving ridges and subgrooves with plastic film mulching in a millet-field pea-spring wheat-potato cropping system. The study was conducted in a typical semiarid area, during the four annual growing seasons of 2005–2008 and five treatments were designed: (1) a flat plot with no mulching, which is the conventional tillage practice (CK); (2) alternating ridges and furrows with no mulching (M0C0); (3) alternating ridges and furrows with no mulching, and subgrooves mulched with plastic film (M0C); (4) alternating ridges and furrows, with only the ridges mulched with plastic film on the surface (MC0); and (5) alternating ridges and furrows, as well as subgrooves, with the ridges and subgrooves mulched with plastic film (MC). The subgrooves with plastic film mulching increased topsoil temperature, the average daily soil temperature of the 4-growing seasons was 16.7, 16.8, 16.9, 17.4 and 17.2 °C for the CK, M0C0, MC0, M0C and MC, respectively. The soil temperature was significantly higher in the M0C and MC than in the CK, M0C0 and MC0 in May 2006, September in 2007 and May 2008. In average and wet years, the soil water content in the 20–40 cm soil layer was 6.2–37.7% higher in the MC than in the CK. The ridges and subgrooves with plastic film mulching improved crop yields, and the average yield over the four years was higher in the MC than in the CK, M0C0, M0C and MC0 by 163%, 98%, 62% and 21%, respectively. Potato is a staple and economic crop in this region, and the ratio of large and moderate-sized potato tuber yield to total tuber yield was 21.7% higher in the treatments with subgrooves than in the treatments without subgrooves. In conclusion, the technique of ridges and subgrooves with plastic film mulching is an effective practice for improving crop yields in semiarid agroecosystems.