Synergistic effect of tillage-nitrogen interaction on grain yield and quality of dryland wheat

Objectives This study investigated the effects of different tillage practices and nitrogen (N) application rates on grain yield and quality of dryland wheat, aiming to propose an optimal combination of tillage practice and nitrogen rate.

Methods Field experiments for winter wheat with split-plot design were conducted across 2020−2022 at three sites—Mengjin District, Yichuan County and Luoning County of Luoyang City, Henan Province—a typical dryland wheat production region located at the junction of the Loess Plateau and the Huang-Huai-Hai Plain. The main plots consisted of three tillage practices: rotary tillage (RT), plow tillage (PT), and subsoiling (SS). The subplots included four N application rates: 0, 120, 180, and 240 kg/hm², denoted as N0, N120, N180, and N240, respectively. At maturity, grain yield were investigated, and grain Zn content, total protein and protein components, as well as processing quality paramters were measured.

Results Tillage practice, N application rate and their interaction significantly influenced wheat yield and quality in most cases. Under the same N application rate, SS treatments produced the highest grain yield and Zn content, which were 6.3%−25.4% and 10.7%−40.3% higher than those under RT treatments, and 3.9%−11.3% and 3.7%−24.1% higher than those under PT treatments, respectively. These increases became more pronounced with increasing N application rates. Furthermore, the yield increase under SS was higher in the 2021−2022 season than in 2020−2021. Compared to RT and PT, SS significantly increased the contents of total protein and protein components, as well as processing quality indices, across the three experimental sites. With the increase of N application rates, wheat yield, grain Zn content, total protein and protein component contents, and processing quality under all three tillage practices increased initially and then stabilized. Except for globulin content at Yichuan in 2021−2022, no significant differences were observed between N180 and N240, both of which showed significantly higher yield and quality than N120. Further more, SSN180 exhibited similar yield and quality with SSN240, except for maximum resistance at Luoning in 2020−2021.

Conclusions Subsoiling combined with N application rate of 180 kg/hm² is a suitable combination for high yield while maintaining nutritional and procession quality in dryland wheat production.