Maize/soybean intercropping improve yield stability in red soil under different phosphate application rates in southwest China

Abstract

Aims Studying the effects of maize and soybean intercropping for improving maize yield, and maintaining stability of maize yield under different phosphate (P) application rates in red soil is important for promoting the maize productivity, improving soil fertility and optimizing P nutrient management in southwest China. The objective of this study was to evaluate the dynamic changes of maize yield, yield stability and soil fertility under monoculture and intercropping maize with different P application rates. Methods A six-year field experiment was conducted from 2017 to 2022 to investigate the effects of maize intercropping with soybean on the yield stability and sustainability of maize according to the changes in maize yield, biomass, Partial land equivalent ratio of yield (pLERY), actual yield loss index (AYL), contribution rate of soil capacity and fertilizer (SCR, SFCR) over time, as well as the differences in coefficient of variation (CV) and sustainable yield index (SYI) at four P application rates (0 kg P ha-1, P0; 60 kg P ha-1, P1; 90 kg P ha-1, P2; and 120 kg P ha-1, P3) based on the two-factor split block design. The linear-platform model was used to simulate the relationship between the grain yield, SYI and the amount of P fertilizer under different P application rates. Results The maize yield in intercropping was significantly superior to the corresponding maize monoculture throughout the six-year experiments. For all planting years, the yield and biomass of the intercropping was higher than that of the matched monoculture average by 56.0% and 56.1%, respectively. And intercropping had an advantage of pLERY and AYL for maize. Otherwise, intercropping reduced the CV by 30.8% and 39.1%, and increased the SYI by 39.4% and 23.0% in P0 and P3 compared with matched monoculture, respectively. For all planting years, the average SFCR in intercropping treatment was higher than that in monoculture treatment. Linear-plateau model fitted showed that intercropping increased yield and SYI by 19.8% and 40.7% on platform, and reduced P application rate by 37.8% and 11.9% at inflection point, respectively. Conclusions These results demonstrate that maize and soybean intercropping could achieve higher yield, higher yield stability and SYI with lower P input than monoculture. Maize and soybean intercropping could be a sustainable practice for promoting the maize productivity and the yield sustainability in red soil of southwest China.