Experimental Data Acquisition

Air temperature was automatically recorded by a small and simple weather station (BN-QX001, Boen, Beijing, China). Soil temperature was measured by geothermal meter (CJ-69, Licheng, Hengshui, China) on 7-day intervals in 5- to 25-cm soil layer with 5-cm intervals, at 08:00, 14:00, and 18:00 h in each of the measuring days, in maize growing season. Soil temperature in 5–25 cm at 08:00, 14:00, and 18:00 h was the average of each soil depth at every measuring day. Soil temperature in 5, 10, 15, 20, and 25 cm was the average of each measuring time at every measuring day. In addition, the difference value between air and soil temperatures was calculated in 5- to 25-cm soil layers in each growth period of different treatments.

Soil accumulated temperature (SAT;°C) was calculated by the following equation:

where ST_i (°C) is soil temperature at various growing stages of maize and Di (days) is the measuring interval time.

Soil gravimetric water content (GWC;%) was measured in 2-week intervals from maize sowing to harvesting with the oven-drying method throughout a sampling soil layer of 0–30 cm in a 10-cm increment. It was measured with a neutron probe (NMM503DR, Concord, CA, United States) throughout a sampling soil layer of 30–120 cm in a 30-cm increment. The oven-drying method was in line with the neutron probe measurements for the measuring places and times. Because a fully mulched system with plastic is used for maize cultivation in arid regions of northwestern China, all soil moisture samples were collected from the section of the plastic mulching.

The WC modulus coefficient (WCMC;%) was calculated by WC of various maize growing stages divided by total WC across the entire maize growing season. The following equation is used to calculate WCMC (Cazcarro et al., 2013):

where WC_i (mm) is WC at various maize growing stages and WC_t (mm) is the total WC.

Meanwhile, the calculation equations of WC_i and WC_t are as follows (Lian et al., 2016):

where P and I are precipitation and irrigation, respectively, of each maize growing stage (mm); ΔSWS is the difference value of soil water storage (mm) in 0- to 120-cm soil layer between the pre- and post-growing stages of maize; and i represents the various maize growing stages.

When maize reached physiological maturity, three rows of unsampled maize plants were selected from each plot, and 3-m length was harvested from each row to evaluate the grain yield of maize. The harvested grain from each plot was weighed, and its moisture content was measured using a grain moisture meter (PM-8188, Shanghai, China). Grain yield was calculated at 13% moisture content, after threshing, cleaning, and air-drying. Use the following equation to calculate water use efficiency (WUE) (kg ha^–1 mm^–1):

The major inputs included labor, machine, plastic, seeds, fertilizers, and irrigation and were recorded in each year. The major output included the economic value on grain and straw for maize (based on the local real-time prices at the time of the experiment). The net income (NI) was determined by calculating the difference between the values of total output and total input, in each treatment. The benefit dominance index (BDI) was determined by calculating the ratio of the net income per unit area of maize production in the experimental area to the average net income per unit area of maize in China; and the data come from the China Statistical Yearbook.