Nitrogen Leaching and Nitrous Oxide Emission fromThree Soils in China

摘要

Through rye grass (Lolium multiflorum) covered soil column experiment wasconducted to study nitrogen leaching and nitrous oxide emission from three Chinesesoils with different physical and chemical properties. Red, yellow and blue soils with tworeplications of each soil samples were considered throughout the experiment and soilswere collected to the plough layer depth (0-30 cm) from three different sites in China.Nitrate concentrations and nitrous oxide emission from soil column surfaces weremonitored for 60 days. During sampling period, soil column were placed in a greenhouse to ensure standard temperature and germination of rye grass. Maximumtemperature of the green house was 29.50C and minimum temperature was 160C thataffected leaching and emission by nitrification and denitrification. But relative humidityhad no remarkable effect on leaching and emission. Nitrogen leaching and N2Oemissions were influenced by soil properties before and after nitrogen and phosphorousfertilizer application and different stages of rye grass from soil column. Nitrogen leachingwas calculated by measuring the nitrate concentration in soil solution relating with theamount of percolation based on the changes in the soil water content within thesampling periods. The value of NO 3-N concentration in the collected soils were higher inblue and red than in yellow soil. Due to temperature, growing and maturity stage of ryegrass and plant N up taking behavior from soil, NO3-N concentrations were fluctuates inall kinds of soil during sampling period. Nitrous oxide gas samples were collected withclose chamber technique and analyzed in the laboratory by gas chromatography. Amongthree soils nitrous oxide emission was higher in blue soil than in yellow and red soils.From this study, it was observed that nitrous oxide emission was higher during the firsttwo weeks of sampling period and becomes constant rest of the sampling period.