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在温室条件下连续种植 4茬玉米和水稻幼苗 ,分别研究好气和淹水条件下土壤无机硫(MCP S)和有机硫包括酯键硫 (C O S)、碳键硫 (C S)和未知态有机硫 (UO S)的转化及生物有效性。结果表明 ,植物吸硫总量和植株含硫量从第一茬至第四茬逐渐下降 ,这与土壤MCP S含量下降有关 ,而与土壤有机硫各组分的变化无关。种植期间土壤MCP S的含量也是逐渐下降 ,种植水稻时下降的幅度小于种植玉米 ;土壤有机硫组分如C O S、C S和UO S从第一茬到第四茬逐渐下降 ,种植 4茬后 ,玉米和水稻的吸硫总量远大于土壤MCP S的下降量 ,其高出部分来源于土壤有机硫的矿化。C O S、C S和UO S对植物都是有效的 ,各组分有机硫对玉米和水稻幼苗吸硫的表观贡献为 :C O S >C S >UO S。淹水条件下有机硫对水稻的贡献大于好气条件下对玉米的贡献
Four successive cropping of corn and rice seedlings under greenhouse conditions were conducted to study the effect of soil organic sulfur (MCP S) and organic sulfur on aerobic and submerged conditions including ester bond sulfur (COS), carbon bond sulfur (CS) and unknown organosulfur (UO S) transformation and bioavailability. The results showed that the total sulfur uptake by plants and the sulfur content of plants decreased gradually from the first stubble to the fourth stubble, which was related to the decrease of MCP S content in the soil, but not to the change of organic sulfur components. The soil MCP S content also decreased gradually during planting, and the decline rate was less than that of corn planting when planting rice. The contents of soil organic sulfur such as COS, CS and UO S decreased gradually from the first stub to the fourth stubble. After 4 stubble crops, And the total sulfur uptake of rice is much larger than the decrease of soil MCP S, which is partly due to the mineralization of soil organic sulfur. C O S, C S and UO S are all effective for plants. The apparent contributions of organic sulfur to sulfur absorption of maize and rice seedlings are: C O S> C S> UO S. The contribution of organic sulfur to rice under flooding conditions was greater than that of aerobic conditions