Intercropping of peanut–tea enhances soil enzymatic activity and soil nutrient status at different soil profiles in Subtropical Southern China

Intercropping is one of the most widely used agroforestry techniques, reducing the harmfulimpacts of external inputs such as fertilizers. It also controls soil erosion, increases soil nutrientsavailability, and reduces weed growth. In this study, the intercropping of peanut (ArachishypogaeaL.)was done with tea plants (Camellia oleifera), and it was compared with the mono-cropping of tea andpeanut. Soil health and fertility were examined by analyzing the variability in soil enzymatic activityand soil nutrients availability at different soil depths (0–10 cm, 10–20 cm, 20–30 cm, and 30–40 cm).Results showed that the peanut–tea intercropping considerably impacted the soil organic carbon(SOC), soil nutrient availability, and soil enzymatic responses at different soil depths. The activityof protease, sucrase, and acid phosphatase was higher in intercropping, while the activity of ureaseand catalase was higher in peanut monoculture. In intercropping, total phosphorus (TP) was 14.2%,34.2%, 77.7%, 61.9%; total potassium (TK) was 13.4%, 20%, 27.4%, 20%; available phosphorus (AP)was 52.9%, 26.56%, 61.1%; 146.15% and available potassium (AK) was 11.1%, 43.06%, 46.79% higherthan the mono-cropping of tea in respective soil layers. Additionally, available nitrogen (AN) was51.78%, 5.92%, and 15.32% lower in the 10–20 cm, 20–30 cm, and 30–40 cm layers of the intercroppingsystem than in the mono-cropping system of peanut. Moreover, the soil enzymatic activity wassignificantly correlated with SOC and total nitrogen (TN) content across all soil depths and croppingsystems. The depth and path analysis effect revealed that SOC directly affected sucrase, protease,urease, and catalase enzymes in an intercropping system. It was concluded that an increase in the soilenzymatic activity in the intercropping pattern improved the reaction rate at which organic matterdecomposed and released nutrients into the soil environment. Enzyme activity in the decompositionprocess plays a vital role in forest soil morphology and function. For efficient land use in the croppingsystem, it is necessary to develop coherent agroforestry practices. The results in this study revealedthat intercropping certainly enhance soil nutrients status and positively impacts soil conservation.

The funding sources include the National Science and Technology Support Grant ofChina (2015BAD07B0503), Forestry Science and Technology Promotion Project of China (No. 122017) and Postdoctoral research funding of Central South University of Forestry and Technology(70702-45200003).