[Effects of optimal nitrogen fertilizer management on water and fertilizer utilization efficiency and yield under double-ridge-furrow sowing with the whole plastic film mulching in maize in a semi-arid area].

Improper fertilization style is one of the main reasons for low water and fertilizer use efficiency of double-ridge-furrow sowing with the whole plastic film mulching in maize production in the semi-arid area. Understanding the effects of reduction, postponing, and organic fertilizer substitution of nitrogen fertilizer on water and fertilizer use efficiency and yield of maize can provide theore-tical basis for effective management of water and fertilizer in maize production. Based on a 4-year field experiment with three treatments: all fertilizers as base fertilizer under double-ridge-furrow sowing with the whole plastic film mulching (CK), nitrogen fertilizer reduced by 15% and topdres-sing in tasseling stage (RN), 30% of the chemical fertilizer replaced by organic fertilizer and topdressing in tasseling stage (RNM), we measured water consumption characteristics, growth and development, water and fertilizer utilization efficiency of maize. The results showed that fertilization pattern significantly affected water and fertilizer utilization efficiency and yield of maize, which was dependent on annual rainfall. In dry and normal rainfall year, water consumption in pre-flowering stage of RN was decreased by 16.1%-18.8% and that in post-flowering stage was increased by 18.0%-22.2%, while water consumption in pre-flowering and post-flowering stages of RNM did not differ from that in CK. In wet year, water consumption in pre-flowering stage of RN and RNM was decreased by 16.7% and 6.3%, while that in post-flowering stage was increased by 11.4% and 29.7%, respectively. Compared with CK, RN significantly increased the relative content of chlorophyll (SPAD) of maize leaves after topdressing, the biomass in post-flowering stage was increased by 15.6%-44.9%, the ear length, the number and weight of grains per spike and the 100-grain weight were increased significantly, yield was increased by 9.8%-17.0%, and water use efficiency (WUE) was increased by 6.3%-21.4%, with the partial productivities of fertilizer (PEP), N (PEP), P (PEP) and K (PEP) were all increased significantly. In conclusion, RN could improve water consumption and the SPAD value in post-flowering stage of maize in different precipitation years, increase post-flowering biomass, and optimize the ear character, obviously improve yield, water and fertilizer use efficiency. It was a effective fertilizer management mode with high-efficiency utilization of water and fertilizer under double-ridge-furrow sowing with the whole plastic film mulching in maize in the semi-arid area.