As China’s High-Standard Farmland Construction Program advances, many dryland wheat fields can now receive a one-off irrigation during the growing season (hereafter, one-off irrigation). To evaluate the effects of tillage practices and nitrogen (N) rates on wheat yield and quality under one-off irrigation, we conducted a two-factor split-plot experiment from 2020 to 2022 at three sites in Luoyang, Henan province (Xiaolangdi town, Mengjin county; Yaling town, Yichuan county; and Xiaojie town, Luoning county). Tillage practice was the main-plot factor—rotary tillage (RT), subsoiling (SS), and plough tillage (PT)—and N rate was the subplot factor at 0 (N0), 120 (N120), 180 (N180), and 240 (N240) kg hm-2. We measured grain yield, protein content and protein fractions, grain Zn content, and key processing-quality traits. Tillage practice and N rate significantly affected wheat yield and quality; their interaction significantly influenced grain yield, protein yield, and the contents of all protein components except albumin. Compared with PT and RT, SS increased grain yield by 6.9% and 12.6%, respectively, and increased protein yield by 7.7% and 14.5%, while generally improving protein content, most protein fractions, processing quality, and grain Zn content (with a few site-year exceptions). Relative to PT, SS increased albumin, globulin, gliadin, and glutenin contents as well as dough development time, stability time, wet gluten content, sedimentation value, extensibility, maximum resistance, and grain Zn content by 21.9%, 19.0%, 12.5%, 8.0%, 18.6%, 28.4%, 8.2%, 26.4%, 10.1%, 14.0%, and 12.6%, respectively; compared with RT, the corresponding increases were 22.0%, 19.6%, 19.7%, 15.0%, 19.5%, 32.8%, 9.1%, 27.8%, 10.3%, 22.6%, and 23.2%, respectively. Across all tillage practices, increasing N rate led to an initial increase followed by a plateau in yield, protein yield, protein fractions, processing-quality traits, and grain Zn content. In most cases, N180 and N240 did not differ significantly, and both outperformed N120. Except for grain yield at the Xiaolangdi site and gliadin content in 2021-2022, SSN180 achieved similar yield, quality, economic returns, and input-output ratio to SSN240, while outperforming the other treatments in most comparisons. Overall, subsoiling combined with 180 kg hm-2 N is recommended for dryland regions where one-off irrigation is available, as it can simultaneously improve wheat yield, quality, and economic benefits.
WeChat