Variation of the carbon budget and comparison between static chamber method and eddy covariance method in the Reaumuria soongorica -Salsola passerina community in the Tennger Desert Comparative analysis of evapotranspiration rates of tea crops before and after pruning in the Western Hills of the Tai Lake Basin Short-Term Effects of Clear-Cutting of Populus deltoides Plantation on Methane Flux on the Beach Land of Yangtze River