龙脊稻作梯田休闲期的土壤水分、养分与酶活性特征

Soil moisture,nutrients and enzyme activities during interval condition in Longji rice terrace fields

为了解休闲期稻作梯田的土壤水分、养分和酶活性特征对提高梯田土壤有机碳的固持水平状况的影响,在广西龙脊梯田景区内采集休闲期19个稻田土壤样品,测定土壤养分和酶活性,结果表明:龙脊稻作梯田土壤水分、pH、有机碳、总氮、碱解氮、总磷和速效磷的平均值分别为40.58%、4.76、18.82 g/kg、1.97 g/kg、97.51 mg/kg、0.32 g/kg和68.61 mg/kg,土壤蔗糖酶活性、脲酶活性和酸性磷酸酶活性的平均值分别为5.01 mg/(g·24 h)、4.02 mg/(g·24 h)和9.75 mg/(g·2 h);土壤水分含量与土壤总有机碳含量和3个土壤酶活性之间均呈显著的正相关关系,归一化的土壤养分和归一化的土壤酶活性之间呈显著的正相关关系。综上,在休闲期提高土壤水分有利于龙脊稻作梯田土壤总有机碳的固持和土壤酶活性的提高。

It is of great significance to study the characteristics of soil moisture,nutrients and enzyme activities during interval condition in rice terrace for soil organic carbon(SOC)sequestration.Nineteen soil samples(0-20 cm)were collected in scenic area of Longji rice terrace fields to determine soil moisture,nutrients and enzyme ac-tivities in March,2016.The results showed that the average values of soil moisture,pH,SOC,total nitrogen,al-kali-hydrolyzed nitrogen,total phosphorus and available phosphorus were 40.58%,4.76,18.82 g/kg,1.97 g/kg,97.51 mg/kg,0.32 g/kg and 68.61 mg/kg,respectively.The average activities of sucrase,urease and acid phosphatase were 5.01 mg/(g·24 h),4.02 mg/(g·24 h)and 9.75 mg/(g·2 h),respectively.Statistical a-nalysis showed that there was a significant positive relationship of soil moisture with SOC and the activities of the three enzymes.There was also a significant positive correlation between normalized soil nutrient and normalized soil enzyme activity.The above results indicated that improving soil water moisture during interval could increase SOC sequestration and improve soil enzyme activities in Longji rice terraces.