Black plastic film combined with straw mulching delays senescence and increases summer maize yield in northwest China

Ridge-furrow farming systems with transparent plastic film have been used extensively for maize (Zea mays L.) production in semi-arid areas. However, with climate warming, problems may arise associated with premature senescence and reduced production. This study examined whether dual mulching of ridges with black plastic film and furrows with straw can delay senescence and increase summer maize yield. Summer maize cultivation experiments were conducted in 2014-2015 by ridge-furrow planting with black (BRM) or transparent (TRM) plastic film mulch over the ridge and wheat straw mulch over the furrow, flat planting with black (BM) or transparent plastic film mulch (TM), and flat planting without mulch (control treatment, CK). The objective of this experiment was to determine the effects of the different mulching treatments on soil water and temperature, evapotranspiration (ET), leaf, photosynthesis rate, yield, and water use efficiency of summer maize. The BRM and TRM treatments were superior to the BM and TM treatments in terms of soil water storage in the 0-200 cm soil profile. The BRM reduced the diurnal variation in the soil temperature and lowered the soil temperature in the root zone. The BRM treatment extended the maize reproductive growth period by 5 days compared with TM, and 2-3 days longer than for the other mulched and control treatments. The BRM also increased the leaf area and dry matter accumulation per plant while significantly increasing the leaf photosynthesis rate. Moreover, BRM increased the 100-seed dry weight and significantly improved yield and water-use efficiency. The 2-year average yield of the BRM treatment was 6.7, 13.4, 18.4, and 72.9 % greater than yield of the TRM, BM, TM, and CK treatments, respectively. The corresponding water-use efficiency improved by 11.2, 13.1, 20.3, and 72.1 %, respectively. Applying the BRM cultivation practice will effectively delay senescence and increase summer maize yield in the agricultural production area of the study region.