The Effect of Intercropping with Eucommia ulmoides on the Growth and Quality of Abelmoschus manihot and Its Rhizosphere Microbial Community

Intercropping is a specific agricultural practice where multiple crops are alternately planted in the same field, focusing on optimizing crop interactions and resource use. The key advantages of this approach encompass the complementary ecological niches of crops, which facilitate efficient resource utilization, promote soil microbial diversity, and ultimately lead to enhanced crop yield and quality. Within this context, rhizosphere microorganisms play a pivotal role in plant growth, not only maintaining crop health but also augmenting resistance to various stressors through intricate mechanisms, such as colonizing the plant rhizosphere to produce phytohormones that stimulate plant growth, activating plant defense systems, and competitively excluding soil pathogens. Abelmoschus manihot (A. manihot) is widely distributed and possesses medicinal value; thus, it is utilized to treat a variety of diseases. When cultivating A. manihot, we hope to make rational use of limited planting space, while ensuring the yield of A. manihot and enhancing its medicinal quality. Therefore, a field experiment was conducted in which two planting patterns for A. manihot were designed. Monocropping plots featured A. manihot planted at 0.3 m intervals with a row spacing of 0.5 m. In the intercropping plots, A. manihot was also planted at 0.3 m intervals, maintaining a row spacing of 0.5 m. Furthermore, Eucommia ulmoides (E. ulmoides) was planted at 0.3 m intervals, with a row spacing of 0.25 m between A. manihot and E. ulmoides. Through the field experiment, we evaluated the effects of monocropping and intercropping with E. ulmoides on the quality and biomass of A. manihot, as well as the rhizosphere microbial community structure. The results showed that intercropping can promote the growth of A.manihot, especially by increasing the number of flowers and fruits, but the quality of the medicinal properties is not affected. Specifically, in 2024, the number of flowers in the intercropping plants was 20 ± 2, compared to 13 ± 2 in the monocropping; in 2023, the number of fruits in the intercropping plants was 19 ± 2, compared to 13 ± 2 in the monocropping; and in 2024, the number of fruits in the intercropping plants was 20 ± 2, compared to 13 ± 2 in the monocropping. This effect is due to the self-regulation of A. manihot in response to the biological stress from E. ulmoides. The composition and function of the A. manihot rhizosphere fungal community in the intercropping system changed significantly, which may be the reason for the growth and development of A. manihot. This discovery reveals the potential of intercropping as an agricultural practice in promoting plant growth and increasing yield. Intercropping with E. ulmoides significantly promoted the growth of A. manihot, increasing the number of its flowers and fruits without compromising the quality of its medicinal properties. This finding offers valuable insights for agricultural production: by employing rational intercropping configurations, crop yields can be increased without compromising crop quality.