Study site and sampling
The study was conducted in two locations: Hainan Island and Bnna. Hainan Island experiences a tropical maritime monsoon climate, characterized by a rainy season from May to October and a dry season from November to April. Rubber plantations in Hainan are located at low latitudes and altitudes, making them tropical island-type plantations. On the other hand, Bnna has a warm and humid climate throughout the year, with dry (November to April) and rainy seasons (May to October) similar to Hainan. The rubber plantations in Bnna are situated at higher latitudes and altitudes, representing a tropical inland static wind plantation area type with fertile soil (Lan et al., 2020).
We selected six major plantation sites from Danzhou, Wanning, and Ledong Districts in Hainan Island, as well as from Jinghong, Menglun, and Mengpeng Districts in Xishuangbanna (Figure S1). At each site, we chose three plots separated by distances of 5-15 km for sampling, resulting in a total of 18 plots. The sample collections were carried out in August to September 2019 and November to December 2020, corresponding to the rainy and dry seasons, respectively. Therefore, we obtained 36 soil samples from each plot, resulting in a total of 216 samples, including those from the phyllosphere, leaf endosphere, soil, rhizosphere, rhizoplane, and root endosphere compartments. For each sample, we analyzed water content (WC), pH, leaf phosphorus (P), potassium (K), nitrogen (N), and organic matter (LOM). Additionally, we quantified soil total nitrogen (TN), total phosphorus (TP), total potassium (TK), organic matter (SOM), available potassium (AK), ammonium nitrogen (AN), nitrate nitrogen (NN), and available phosphorus (AP). The soil, root, and leaf sampling approach, as well as the analysis of physicochemical properties, were conducted based on the methods described in our previous study (Lan et al., 2023; Wei et al., 2022a). We collected latitude, longitude, and elevation data for each site. Additionally, data on average monthly precipitation and average monthly temperature for each month were obtained from the National Meteorological Information Center. (https://www.data.cma.cn).