Environmental management Agricultural expansion 1 Agricultural robots 1 Agriculture 1 Biogeochemistry 1 C/N ratio 1 China 1 Climate change 1 Ecosystems 1 Engineering constructions 1 Environmental economics 1 Flow velocity 1 Guangxi Zhuangzu 1 Human activity 1 Hydrological characteristics 1 Land use 1 Natural disasters 1 Nutrient concentrations 1 Organic carbon 1 Particles (particulate matter) 1 Particulate organic carbon 1 Particulate organic matter source 1 Particulate organic matters 1 Regional & area planning 1 Rivers 1 Small mountainous rivers 1 Soils 1 Stable carbon isotope 1 Total suspended solids 1 Tropical small mountainous river 1