Ridge-furrow mulching system regulates diurnal temperature amplitude and wetting-drying alternation behavior in soil to promote maize growth and water use in a semiarid region

Utilizing the ridge- furrow mulching system with plastic film (RFMS) is an effective strategy for improving crop productivity in semiarid areas. However, the key mechanism by which RFMS drives spatiotemporal hydrothermal variation of soil to positively affect crop production is not well-defined, and a better understanding of this mechanism could guide RFMS optimization. A two-year field experiment was conducted with three planting treatments: 1) the RFMS with high coverage ratio, 50 cm mulched ridge:10 cm bare furrow, RFH; 2) the RFMS with low coverage ratio, 60 cm mulched ridge:60 cm bare furrow, RFL; and 3) flat planting without mulching as the control treatment, CK. The results showed that RFMS increased topsoil temperature by 1.0-2.5 degrees C during the day (08:00-20:00) and 1.6-3.4 degrees C at night (20:00-08:00), respectively, compared with CK, which led to a decrease of 0.4-1.3 degrees C in diurnal temperature amplitude, but indicated a strong positive impact on maize growth in the thermally deficient study area. In addition, RFMS drove the spatio-temporal alternation of soil wetting and drying (alternation of high and low SWC) relative to CK, indicating an efficient water use strategy that significantly reduces soil evaporation but promotes the plant transpiration during water sensitive period. These effects in RFH were significantly greater than those in RFL due to its significantly enhanced water infiltration, suppressed evaporation and reduced heat loss, which stimulated vigorous crop growth. This study suggested that, compared to CK, RFH was more efficient than RFL to improve maize production, which increased these amplitudes from 43.1% to 59.2% in grain yield increase, from 38.5% to 57.4% in water use efficiency (WUE) increase and from 71.7% to 95.0% in economic benefit increase, respectively. Therefore RFH can be considered as a superior technique for overcoming simultaneous drought and cold stresses in northwestern China.