Implementing intercropping maintains soil water balance while enhancing multiple ecosystem services

Abstract

Intercropping in plantations may alter soil water consumption, absorption and retention. However, little is known about how soil water changes impact ecosystem services. In the present study, we planted Alpinia oxyphylla Miq. (a medicinal herb) in rubber (Hevea brasiliensis) plantations and monitored daily soil water content in the surface (0–20 cm), middle (20–40 cm), and deep (40–60 cm) soil layers after intercropping. We analyzed the impact of soil water connected with ecosystem properties such as hydraulic conductivity, soil organic matter, root length density, and canopy density on water regulation, soil retention, soil fertility (available N, P, and K), and biodiversity (bacterial and eukaryotic diversity). Our results showed that intercropping significantly increased and decreased soil water consumption by 54.34% and 36.78% in the surface and middle soil layers, respectively. Water absorption increased by 52.93% and decreased by 39.58% in the surface and middle soil layers, respectively. Hence, water was replenished, and the water balance was maintained across soil layers. Moreover, soil water absorption rather than consumption, with hydraulic conductivity and root length density, predicted increases in water regulation and soil retention. Soil water retention positively promoted soil bacterial diversity, which could increase available P content in the surface soil layer. Our results confirmed that intercropping balanced soil water distribution and improved several ecosystem services without increasing water consumption across the entire system. Hence, intercropping does not exacerbate the water deficit. We propose that adaptive and profitable intercropping in rubber plantation should protects crop production and ecosystem services while promoting sustainable land use.