STUDY ON SIMULATED ACID PRECIPITATION EFFECTS ON GROWTH AND YIELD OF AGRICULTURAL CROPS
模拟酸雨对农作物生长和产量影响的初步研究

This paper deals with acid precipitation effects on growth and yie-1d of wheat, rice, soybean and Chinese cabbage. Simulated acid precipi-tation contained known concentration of ions of natural acid precipitationin Southern China. The pH values of simulated acid precipitation were5.6, 4.5, 4.0, 3.5, 2.5 and 2.0. The results indicated that visible damage threshold of soybean andChinese cabbage was 2.5 of pH value, and the visible damage thresholdsof rice and wheat were 2.0 and 3.0 pH values, respectively. Conductivi-ty of soybean and Chinese cabbage increased with decreasing pH valueof acid precipitation. A 3.5 pH value acid precipitation could cause areduction in the chlorophyll content in Chinese cabbage, a 3.0 pH valueacid precipitation could cause a reduction in the chlorophyll content insoybean and wheat. The Ratio of chlorophyll a to chlorophyll b waschanged. A pH 3.5 pH value acid precipitation inhibited the growth of Chine-se cabbage, and a 3.0 pH value acid precipitation inhibited the growthof wheat and soybean. A pH 3.5 pH value acid precipitation caused yi-eld reduction of wheat and Chinese cabbage. A 3.0 pH value acid preci-pitation caused yield reduction of soybean. Growth and yield of rice we-re not affected by a 2.5 pH value acid precipitation. The yield reducti-on of wheat and soybean resulted from reduction of seed weight was ma-inly caused by acid precipitation.