Impacts of different soil fertility improvement practices with film mulched ridge-furrow til-lage on soil nutrient content, maize yield, and water use efficiency in Northwest China.

Abstract

Improvement of soil quality is one of the most important ways to enhance fertility for efficient dryland crop production. However, the effects of different fertilization measurements with film mulched ridge-furrow tillage on soil fertility, crop yield, and water use efficiency (WUE) of maize largely remain unknown. A three-year field experiment was conducted at the Zhuanglang Experimental Station, Gansu Academy of Agricultural Sciences, located in the semiarid region of the Loess Plateau, Northwest China during 2014-2016. Maize breed Funong No.1 was used during the study. There were four treatments, including: 1) conventional planting (CP, served as control), 2) film mulched ridge-furrow with straw incorporation (FS), 3) film mulched ridge-furrow with optimizing fertilization (FF), and 4) film mulched ridge-furrow with controlled fertilization (FC). Seasonal and yearly changes of soil water content, topsoil organic matter (SOM), soil available nitrogen (AN), phosphorus (AP) and potassium (AK) concentration and crop yield were measured. Nitrogen and phosphorus fertilizer partial factor productivity (PFPN and PFPP), soil profile water storage (WC), crop seasonal water consumption (ET) and water use efficiency (WUE) were calculated. The results showed that FS, FF and FC effectively improved soil fertility via synergistic regulation of soil hydrothermal and nutritional condition. Water-fertilizer interaction effect greatly enhanced incorporated straw decomposition and crop growth, resulting in more returning of straw nutrients and crop biomass to soil, thus significantly increased soil water and fertilizer supply capacity. Compared to CP, the three treatments of FS, FF and FC efficiently increased the concentrations of SOM, AN, AP, and AK by 0.27 g·kg-1, 4.44 mg·kg-1, 0.20 mg·kg-1 and 4.53 mg·kg-1 with an order of FC＞FF＞FS, but had no significant difference among them. Meanwhile, in contrast to pre-sowing WC200, the three year's sum of FS,FF and FC increased WC200 at the end of growing season by 107.41, 38.99 and 28.35 mm, respectively. On average, FS, FC and FF significantly reduced maize ET by 60.50, 37.7 and 34.15 mm to CP, with a relative decrease of 12.6%, 7.9% and 7.1% respectively. By the synergistic effect of modified water and fertilizer environment, the three soil fertility improvement strategies greatly enhanced maize growth from tasseling to maturity stages in the relatively dry year. They affected maize growth in relatively more rain and warmer year, resulting in significantly increased maize yield by improving the yield traits (double ear rate, grain number per ear and 100-grain mass), PFPN, PFPP and WUE. Compared to CP, the PFPN,PFPP of FS, FF and FC increased by 1.82, 1.65, 1.62 and 2.41, 1.69, 1.63 times respectively. Yield and WUE were increased by 5986.1, 4972.31, 4585.63 kg·hm-2 and 13.27, 12.65, 14.01 kg·mm-1·hm-2 correspondingly raised by 81.5%, 67.7%, 62.5% and 86.5%, 82.5%, 91.3%. In conclusion, FS was more effective in water harvesting and drought resistance, while FC and FF were effective for high yield.