Long-term chemical and organic fertilization differently affect soil aggregates and associated carbon and nitrogen in the Loess Plateau of China

Authors: YANG, CAIDI - Northwest University; Sainju, Upendra; LI, CHAO - Northwest University; FU, XIN - Agricultural University Of Hebei; ZHAO, FAZHU - Northwest University; WANG, JUN - Northwest University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2023
Publication Date: 5/25/2023
Citation: Yang, C., Sainju, U.M., Li, C., Fu, X., Zhao, F., Wang, J. 2023. Long-term chemical and organic fertilization differently affect soil aggregates and associated carbon and nitrogen in the Loess Plateau of China. 13(6). Article 1466. https://doi.org/10.3390/agronomy13061466.
DOI: https://doi.org/10.3390/agronomy13061466

Interpretive Summary: Extensive use of chemical fertilizers for the last several decades has degraded soil aggregation and stability and declined winter wheat yield in China. Alternative source of fertilizers is needed to enhance soil aggregation, carbon and nitrogen storage in aggregates, wheat yield. ARS researcher in Sidney, MT in collaboration with researchers from Northwest University, Xian, China evaluated the long-term effect of organic manure, chemical fertilizers, and their mixture on soil aggregation and stability, aggregate-associated carbon and nitrogen, and winter wheat yield in central China. They reported that a mixture of organic manure and chemical fertilizer improved soil aggregation and stability, aggregate-associated carbon and nitrogen, and winter wheat compared to chemical fertilizer alone or no fertilization. Application of organic manure alone enhanced soil aggregation and carbon and nitrogen storage, but reduced wheat yield compared to chemical fertilizers. Replacing chemical fertilizers by a mixture of organic manure and chemical fertilizer can enhance soil health by increasing soil aggregation and stability and carbon and nitrogen sequestration and sustain winter wheat yield under dryland cropping systems in the Loess Plateau of China.

Technical Abstract: Fertilizer sources may have variable effects on soil aggregation, aggregated associated C and N, and wheat yield. A 34-year-old field experiment was performed to evaluate the effect of chemical and organic fertilization on soil aggregation and associated C and N under winter wheat in a Cumulic Haplustoll in the Loess Plateau of China. Treatments included an unfertilized control (CK), inorganic N fertilizer (NF), inorganic P fertilizer (PF), inorganic N plus P fertilizer (NP), organic manure (M), inorganic N fertilizer plus manure (NM), inorganic P fertilizer plus manure (PM), and inorganic N plus P fertilizer plus manure (NPM). Compared to CK and chemical fertilizers, manure with or without chemical fertilizers increased the proportion of soil macroaggregates (>2 mm), mean weight diameter (MWD), and geometric mean diameter (GMD), but decreased the fractal dimension. Aggregate-associated soil organic C (SOC), soil total N (STN), particulate organic C (POC), and microbial biomass C (MBC) were also greater in manure with or without chemical fertilizers than chemical fertilizers or CK in all aggregates. The reverse was true for C/N ratio in all aggregates. Average winter wheat (Triticum aestivum L.) yield across years was greater with NP, PM, and NPM than other treatments. Organic manure with or without chemical fertilizer can enhance soil aggregation and stability, aggregated associated C and N, and winter wheat yield compared to chemical fertilizer alone or no fertilization.