造纸废水灌溉对芦苇湿地根际土壤酶活性的影响

Influence of Papermaking Wastewater Irrigation on the Enzyme Activities in Reed Wetland Rhizosphere Soil

为了探究废水灌溉条件下芦苇湿地根际土壤酶活性变化趋势及其影响因素,以辽滨苇、盘锦苇、小紫散穗等天然混栽芦苇为试材,采用桶栽方法,设置不同浓度(60,120,180,240,300 mg·L-1)造纸废水灌溉芦苇试验,测定芦苇根际土壤中脲酶、磷酸酶、脱氢酶活性,并分析根际土壤酶活性动态变化规律及其与土壤理化性质的相互关系。结果表明:清水灌溉条件下,在芦苇不同生育期,土壤脲酶活性在发芽期最大,为0.57mg NH3-N·(g±24h)-1。磷酸酶活性在快速生长期达到最大值,为0.93mg酚·(g±24h)-1,但各时期脲酶与磷酸酶活性变化差异不显著。脱氢酶活性在快速生长期达到最大值0.092μg TPF·g-1·20h-1,各时期间差异显著;废水灌溉显著提高了芦苇根际土壤脲酶、磷酸酶、脱氢酶活性,3种酶活性受废水浓度影响,在同一生育时期,土壤中3种酶活性均随着废水浓度的增加而增大,在快速生长期废水浓度为300mg·L-1时,脲酶、磷酸酶、脱氢酶,3种酶活性均达到最大值,分别为:2.76 mg NH3-N·(g±24h)-1,1.377mg酚·(g±24h)-1和0.426μg TPF·g-1·20h-1;相关分析表明3种酶活性之间极显著正相关,脲酶、磷酸酶、脱氢酶活性与土壤呼吸强度正相关且相关系数最大,其中脱氢酶与土壤呼吸强度相关系数为0.917,3种酶活性与土壤全氮、全磷显著正相关,与p H值、容重显著负相关。说明芦苇湿地造纸废水灌溉不仅增加了土壤中的养分含量,也提高了根际土壤酶活性。

In order to explore the change trend and the influencing factors of enzyme activitiesin reed wetland rhizosphere soilunder the condition of wastewater irrigation, Liaobin reed,Panjin reed,Phragmitescommunis and other natural mixed planting reedswas taken as the test materials, barrel cultivation was used and the reeds were irrigated with different concentrations of wastewater（60,120,180,240,300mg.L-1）. The activities of urease, phosphatase and dehydrogenase in reed rhizosphere soil were detected. Thedynamic changing law of rhizosphere soil enzyme activities and the correlation between the enzyme activities and the physical andchemical properties of reed rhizosphere soil were analyzed. The results were as follows： under the condition of clean water irrigation,during the different growth stages of reeds, the activities of urease reached the maximum 0.57mg NH3-N.（g·24h）-1 in germinationstageand phosphatase reached the maximum 0.93mg phenol.（g·24h）-1 in rapid growth period. There was no significant differencebetween the changes of soil urease and phosphatase while there was significant difference between their dehydrogenase activities andthe activities of dehydrogenase reached the maximum 0.092μg TPF.g-1.20h-1. Besides, wastewater irrigation significantly improved theactivities of urease, phosphatase and dehydrogenase in reed rhizosphere soil and it showed the change trend of decline after risingfirst along with the rapid growth periods; the enzyme activity was affected by the concentration of wastewater; in the same growthstage, the activities of the three kinds of enzymes in soil increased along with the increase of wastewater concentration; during therapid growth period, when the wastewater concentration was 300mg.L-1, the activity of the three kinds of enzymes reached themaximum and the values were 2.76mg NH3-N.（g·24h）-1, 1.377mg phenol.（g·24h）-1, 0.426μg TPF.g-1.20h-1, respectively. In addition,the correlation analysis showed that there was extremely significant positive correlation between the activities of the three kinds ofenzymes, the three kinds of enzymes had the positive correlation with soil respiration and the correlation coefficient betweendehydrogenase and soil respiration intensity was 0.917. The activities of urease, phosphatase and dehydrogenase was significantlypositively correlated with soil TN and TP, while it was significantly negatively correlated with pH value and soil bulk density. Reedwetland papermaking wastewater irrigation not only increased soil nutrient content, but also improved the rhizosphere soil enzymeactivities