大豆根系分泌物对土壤团聚体大小和稳定性的影响

Effect of Soybean Root Exudates on Soil Aggregate Size and Stability

采用水培实验法收集大豆植株根系分泌物,添加到黑土中,在25℃下培养30d,研究了大豆根系分泌物对土壤水稳性团聚体大小、稳定性、土壤有机碳矿化率、土壤水溶性糖和多糖含量的影响。结果表明,大豆根系分泌物添加到土壤中,显著提高了土壤有机碳矿化率(P<0.05),增加了土壤中水溶性糖和多糖含量(P<0.05),但二者均随培养时间的推移而下降。大团聚体(粒径>1mm)的比例随培养时间的延长而显著增加(P<0.05),小团聚体(粒径<0.1mm)的比例随培养时间的延长而显著降低(P<0.05)。水稳性团聚体含量皆显著高于对照(P<0.05)。培养时间越长,水稳性团聚体含量越高。培养1d时,添加大豆根系分泌物的土壤水稳性团聚体比例是对照的2.7倍。

Root exudates, collected from soybean （ C, tycine max （ L. ） Merr. ） plants under hydroponic conditions, were added to black soil incubated for 30 days at a temperature of 25 degrees C. The effects of soybean root exudates on soil aggregate size and stability were studied. Results showed that addition of soybean root exudates to black soil significantly increased soil organic carbon mineralization and contents of water-soluble sugar and polysaccharide, but they both decreased with the prolonged incubation time. The proportion of macroaggregates（ greater than 1 mm）obviously increased and that of soil microaggregates （less than 0.1 ram） markedly decreased with the prolonged incubation time. The content of water-stable aggregates was higher than that of the control. The proportion of water-stable aggregates of the soil with soybean root exudates on the first day of the incubation multiplied 2.7 times compared with the control.