A mixture of summer legume and nonlegume cover crops enhances winter wheat yield, nitrogen uptake, and nitrogen balance

Authors: ZHANG, SHAOHANG - Northwest University; WANG, JUN - Northwest University; Sainju, Upendra; RAZA, MUHAMMED - Islamia University Of Bahawalpur

Submitted to: European Journal of Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2024
Publication Date: 10/2/2024
Citation: Zhang, S., Wang, J., Sainju, U.M., Raza, M.A. 2024. A mixture of summer legume and nonlegume cover crops enhances winter wheat yield, nitrogen uptake, and nitrogen balance. European Journal of Agronomy. 5, 871-890. https://doi.org/10.3390/nitrogen5040056.
DOI: https://doi.org/10.3390/nitrogen5040056

Interpretive Summary: In the Loess Plateau of China, lands are usually kept under fallow after winter wheat harvest during the summer, which results in enhanced soil erosion due to intense monsoon rain. Summer cover crops can cover soil, reduce soil erosion, and enhance succeeding winter wheat yield and quality and nitrogen relations compared to no cover crop. An ARS scientist in collaboration with Northwest University, Xian, China conducted a four-year study on the effect of four summer cover crops (legume, nonlegume, a mixture of legume and nonlegume and no cover crop) and three nitrogen fertilization rates on winter wheat yield, quality, and nitrogen relations in the Loess Plateau of China. They reported that a mixture of legume and nonlegume cover crops with a nitrogen fertilization rate of 120 kg N/ha increased cover crop biomass and N accumulation, soil mineral nitrogen, and winter wheat yield, protein concentration, nitrogen uptake, and nitrogen balance compared to nonlegume or no cover crop. Producers can enhance winter wheat yield, quality, and soil nitrogen reserve as well as control soil erosion by adopting a mixture of summer legume and nonlegume cover crops with 120 kg/ha fertilizer nitrogen in the semiarid region of the Loess Plateau of China, a region similar to the northern Great Plains, USA.

Technical Abstract: Cover crops protecting soil erosion during the summer fallow period in the monsoon weather may enhance dryland winter wheat yield and N relations. The effects of four summer cover crops and three N fertilization rates were examined on winter wheat yield, quality, and N relations from 2017-2018 to 2020-2021 in the Loess Plateau of China. Cover crops were soybean (Glycine max L., SB), sudangrass (Sorghum sudanense [Piper] Stapf, SG), soybean and sudangrass mixture (SS), and no cover crop (CK) and N fertilization rates were 0, 60, and 120 kg N ha-1 applied to winter wheat. Cover crop biomass and N accumulation, soil mineral N to a depth of 20 cm, winter wheat yield, and N relations were determined. Cover crop biomass and N accumulation, soil mineral N, and winter wheat yield, protein concentration, and N uptake were greater with SB and SS than other cover crops at most N fertilization rates and years. Nitrogen fertilization rate has variable effects on these parameters. Winter wheat aboveground biomass and grain N productivities and recovery indices were greater with CK than other cover crops at all N fertilization rates and years. Nitrogen balance was greater with SS than other cover crops at 60 and 120 kg N ha-1 in all years. Because of the reduced effect of SB on ecosystem services, SS with 120 kg N ha-1 can enhance soil mineral N, dryland winter wheat yield and quality, and N balance compared to CK and SG with or without N fertilization rates.