3种南方绿肥腐解特征及其对淹水土壤养分和酶活性的影响

利用尼龙网袋法,盆栽模拟淹水土壤环境,研究南方常见绿肥紫云英、油菜和肥田萝卜的氮磷释放规律及其对淹水土壤酶活性的影响,绿肥翻压鲜重量为1.14 kg/m~2。在97 d的试验周期内,绿肥腐解率表现为:肥田萝卜紫云英油菜。3种绿肥向土壤环境中释放氮速率由高到低为:肥田萝卜油菜紫云英,并促进了总氮由土壤→溶液的释放,且土壤溶液97 d氮的平均增加量达到显著水平(p0.05)。磷的释放为:肥田萝卜紫云英油菜,其97 d土壤磷的平均增加量达到显著水平(p0.05);绿肥翻压显著影响了土壤多酚氧化酶和转化酶活性(p0.05)。同一种土壤酶在不同处理之间及同一处理条件下的不同酶之间均表现出显著的相关性(p0.05),即土壤酶在促进物质转化中不仅显示其专性催化特性,同时也体现了共性关系。3种绿肥中肥田萝卜改善土壤酶活性作用最明显。

Effects of Three South Green Manures on Flooded Soil Nutrient and Enzyme Activities and Their Decomposition Properties

The changes of nitrogen and phosphorus release and enzyme activity after ploughed green manure of milk vetch, rape and radish of 1.14 kg/m2 of each ina nylon bag were studied., The results showed that the decomposition rate was in the order radish> milk vetch> rape; The order of release rate of TN from the manure into soil was radish >rape >milk vetch, and the actions of release rate of TN from soil into soil solution were also accelerated and the effects reached to significant level(p<0.05); The release rate of TP from the manure into soil was also increased significantly, and the order was radish> milk vetch> rape. The effect of green manure on soil polyphenol oxidase and invertase were significant(p<0.05); The positive relationships between different green manure treatments based on the same enzyme activities were very high, at the same time, there were some significant correlations among different enzymes based on same treatment(p<0.05), which indicating that soil enzymes showed specific catalytic properties as well as isomorphic correlations; Among the three green manures, radish was the most important in improving soil enzyme activities.