Biochar application to cropland has been recommended as a strategy to reduce increasing at-mospheric CO2 concentrations and mitigate climate change.However,the direction and magnitude of responses of greenhouse gas(GHG)fluxes to biochar application to cropland remain unclear.Our meta-analysis of 296 observations across 61 studies for the first time quantitatively estimated the effects of biochar amendment on fluxes of three GHGsCO2,N2O,and CH4.The results showed that biochar application led to a significant change in soil GHGs emissions:in general,19%for CO2,−16%for N2O(P<0.05),but no pronounced change in CH4 emissions;in paddy,−5%for CO2,−20%for N2O,but+19%for CH4(P<0.05);in upland,−18%for N2O,+12%for CO2,and high uncertainty for CH4.The responses of soil GHG flux-es to biochar application were regulated mainly by experiment length,biochar application rate,biochar properties,providing a new perspective for more comprehensive understanding on biochar.The bio-char derived from husk was recommended to apply to cropland with an application rate of 20-30 t·ha^(−1).
Xinzhang SongGenxing PanChao ZhangLu ZhangHailong Wang
Although paid to upward shift response to global phenomenon at low zones did not receive increasing attention has been of plant species in altitude as a warming, research on this altitudinal and low latitudinal enough attention. In this study, an investigation was carried out to test the relationship between the upward spread of Moso bamboo （Phyllostachys pubescens） along altitudinal gradient and the increasing air temperature over the past decade within the Tianmu Mountain region, situated in southeastern China. Results showed that the peak elevation of Moso bamboo population establishment rose by an average of 9.8 m （±2.7 m） during the past decade and significant correlation existed with mean annual temperature （P 〈 0.0001, n = 339） but not with annual precipitation （P = 0.7, n = 339）, indicating that the upward shift of Moso bamboo along altitudinal gradients was driven primarily by warming temperatures. This upward shift could potentially reduce biodiversity by altering the species composition of the ecosystem. However, there is also the potential for increased carbon sequestration capacity of local forest systems, which would produce an additional carbon sink to combat rising atmospheric C02 concentrations and future global warming.
SONG Xin-zhangPENG Chang-huiZHOU Guo-moJIANG HongWANG Wei-fengXIANG Wen-hua
