Effects of Intercropping System on Organic Matter Dynamics and Soil Erosion in the Loess Plateau: Findings from a 3-Year Experiment

Aims: Maintaining the dynamic balance of organic matter is crucial for crop production, sustainable soil development, and the prevention of soil erosion. Methods: A field experiment was carried out for three consecutive years (2021-2023), various fertilizers and planting methods on maize and wheat. The study assessed grain yield, quality, total soil carbon and mineralization, microbial activities, soil erosion and the dynamic changes in soil organic matter in the Loess Plateau. The study utilized three types of fertilizers: inorganic fertilizer (F1), organic fertilizer (F2), and bio-fertilizers (F3). The planting methods examined were maize mono-culture (T1), wheat mono-culture (T2), and maize-wheat intercropping (T3). Results: Compared to inorganic fertilizers, the application of organic biological fertilizers significantly increased crop yields, and the yields of maize and wheat under intercropping (F3T3) were higher than those under monoculture. The soil organic carbon (SOC) content was 32.94% and 37.31%, representing increases of 13.23% and 38.63%, respectively, compared to the unfertilized treatment (F2T3). The soil erosion rate showed a decreasing trend under the F3T3 treatment. The yield and quality of maize and wheat under intercropping conditions (F2T3) exhibited a significant increase compared to monoculture (F2T1 or F2T2) ( p <0.05). While inorganic fertilizers performed well in accumulating short-term available nutrients, they fell short in providing long-term carbon for plants and microorganisms. Total soil carbon exhibited an increasing trend with the duration of fertilization, and the correlation between the selection index and the dynamic movement of soil organic matter was 75.5%. Conclusions: The maize-wheat intercropping under biological fertilizer (F3T3) treatment can serve as an effective management strategy to enhance productivity and soil health in the Loess Plateau.