耕作方式和氮肥用量对旱地小麦产量、水分利用效率和种植效益的影响

为探索旱地小麦增产增效增收协同的耕作方式及其配套施氮技术.2016—2017(欠水年)和2017—2018(丰水年)年度,在豫西典型旱区洛宁县设置夏闲期深松(ST,麦收后2周左右隔年进行)和翻耕(PT,传统的7月或底8月初连年进行)2种耕作方式为主区,设置4个氮肥用量为副区(播前基施纯氮0(N0),120(N120),...

Effects of Tillage Practices and Nitrogen Rates on Grain Yield, Water Use Efficiency and Planting Profit in Winter Wheat in Dryland

The objective of the present study was to explore the suitable combined pattern of tillage practice and nitrogen(N) rate for synchronously increasing the grain yield, water use efficiency and planting benefits in dryland wheat. In the dry year 2016-2017 and wet year 2017-2018, a field experiment was carried out in the typical dryland in western Henan province. In the experiment, the two tillage practices:Subsoiling tillage (ST) and conventional ploughing (PT), were set as the main treatment, and the four N fertilizer application rates of 0, 120, 180 and 240 kg/hm², expressed as N0, N120, N180 and N240, respectively, were set as secondary treatment. The subsoiling in ST was conducted about two weeks after the harvest of previous wheat every two years, and the ploughing in PT was carried out each year around late July to early August after once heavy rainfall. We tested the soil water content, yield and its components, water use efficiency and planting profit. Compared with PT, ST significantly enhanced rainfall fallow efficiency, and increased the water storage in 0-200 cm soil depth by 6.5%~11.7%, 5.0%~8.5% and 4.7%~8.2% respectively at pre-seeding, anthesis and maturity. Therefore, ST significantly enhanced the spike numbers and numbers per spike in the wet year and the 1000-grain weight in the dry year, and thus increased the grain yield and economic return by 7.1%~17.8% and 5.5%~30.2% in the dry year, and increased the grain yield, water use efficiency, economic return by 10.2%~22.0%, 3.0%~13.0% and 16.1%~35.1% in the wet year, compared with PT. With the increase of N rates, the rainfall fallow efficiency was significantly enhanced, resulting in that the water storage at pre-seeding was recovered in PT and significantly increased in ST. N180 was the optimal treatment in PT, and the grain yield, water use efficiency and economic return in N180 was 6.5%~43.9%, 8.1%~36.1% and 12.4%~61.3% higher than those of the other N rate treatments. Under the ST, the optimal N treatment was N180 in the dry year while N240 in the wet year, and the grain yield, water use efficiency and economic return in the optimal treatment was 3.9%~67.9%, 1.0%~54.1% and 3.6%~95.8% higher than those of the other N rate treatments. Above all, subsoiling at about two weeks after the harvest of previous wheat once every two years contributed to accumulating precipitation and increasing soil water storage, and thereby improving grain yield, water use efficiency and planting profit in dryland wheat, particularly with N rate at 180 kg/hm² in the dry year, and with N rate at 240 kg/hm² in the wet year. These results can provide a theoretical basis and technical reference for improving the grain yield, efficiency and profit in dryland wheat.