Effects of long-term maize-peanut Intercropping and Phosphorus Application on C-N-P Content and Stoichiometry in soil Aggregates

This study aims to explore the influences of intercropping and phosphorus application on the contents and stoichiometry of C, N, and P in soil aggregates.

By taking the soil under the 12-year maize-peanut intercropping system as the research object, the size distribution and stability of soil aggregates as well as the contents and stoichiometric characteristics of C, N, and P of aggregates of different particle sizes were hereby explored. The investigation involved three planting patterns of sole maize (SM), sole peanut (SP), and maize-peanut intercropping (M||P), and two phosphorus application levels of phosphorus application (180 kg P ha^− 1, P₁₈₀), and no phosphorus application (0 kg P ha^− 1, P₀).

The results showed that intercropping and appropriate application of phosphorus fertilizer increased the > 0.5 mm aggregate content, and improved the soil aggregate stability. Compared with SP and SM, M||P increased the C, N, and P contents in soil aggregates by 6.16% and 2.22%, 7.59% and 12.85%, 13.29% and 7.06%, respectively; Compared with P₀, P₁₈₀ increased the C, N, and P contents in soil aggregates by 17.73%, 13.55%, and 51.87%, respectively. With decreasing aggregate size, the C/N decreased, with higher C/N observed in SM. Intercropping and phosphorus application decreased the C/P in aggregates, increased the phosphorus availability in aggregates. Phosphorus application decreased the N/P in soil aggregates, accelerated the consumption of soil nitrogen, possibly limiting crop growth due to nitrogen restriction.

Maize-peanut intercropping and phosphate fertilizer application can improve soil aggregate stability and the distribution of C, N, and P in aggregates. This holds considerable significance in maintaining the stability of soil structure and achieving sustainable farmland development in North China Plain.