Study on simulated Acid Precipitation Effects on Growth and Yield of Agricultural Crops Preparation and in-vitro Antioxidant Activity of Proteins from the Larvae of Black Soldier Fly, Hermitia Illucens (Diptera: Stratiomyidae) Effects of Acid Precipitation and Al on Carbon Metabolism in Mycorrhizal Symbionts of Pinus massoniana Tree-Ring Chemical Changes and Possible Impacts of Acid Precipitation in Dinghushan, South China Soil solution chemistry and element budget in the forest ecosystem in Guangzhou Chemical composition, seasonal variation and origin of acid precipitation in typical forest areas in Guangzhou