Impacts of maize and white lupine mixed culture on soil microbial properties, nutrient cycling, and biomass yield and quality: Insights for sustainable soil management practices

Abstract

Intercropping maize with legume is a beneficial farming practice to enhance nutrient use efficiency, among other advantages. The interaction between legume and non-legume rhizobiomes increases soil microbial abundance and stimulates activities related to nutrient acquisition. However, planting patterns in intercropping systems can influence the soil microbial properties of the particular cash crop row. In particular, limited attention has been paid to the dynamics of microbiome-mediated nutrient transformation in strip intercropping systems, especially those with narrow-strip arrangements. Therefore, this work aimed to evaluate the effects of maize (Zea mays L.) and white lupine (Lupinus albus L.) on soil pH and microbial activity in a narrow-strip mixed cropping system comparing them with each other and with a maize monoculture control. A three-year field experiment (mall-scale-plots) was conducted to monitor long-term changes in microbial parameters. Soil pH, the activities of six soil enzymes and three types of substrate-induced respiration were determined annually to assess microbial responses to intercropping over time. Across all three years (2020–2022), the soil from the white lupine row in the intercropping system consistently showed the highest levels of substrate-induced respiration and tendency to increase soil pH(CaCl₂), under initially moderately alkaline conditions. In 2020, enzyme activity in the white lupine row was the most inhibited, while in 2021 it exhibited the weakest phosphorus-limitation, indicating improved phosphorous use efficiency due to maize-legume intercropping. In the same year, the maize row in the intercropping system showed the highest activities of nitrogen-transforming enzymes such as urease and N-acetyl-β-D-glucosaminidase, coupled with highest nitrogen acquisition ratio. By 2022, both maize and white lupine rows stimulated N-acetyl-β-D-glucosaminidase and arylsulfatase activity, indicating enhanced nitrogen cycling potential. Although maize-white lupine intercropping demonstrated partially beneficial impacts on soil microbial activity and nutrient transformation within a single growing season, no significant differences in biomass yield were observed between the intercropped and monoculture maize treatments.