Effects Of Biochar-based Fertilizer And Chemical Fertilizer On Soil N₂O Emssion In Moso Bamboo?Phyllostachys Edulis?forests

Moso bamboo?Phyllostachys edulis?is one of important bamboo forest resources in subtropics.China has the area of Moso bamboo plantation of approximately 4.4 millions hectares,accounting for36%of the world's bamboo forest area.Moso bamboo plantation has unique advantages and great potential in alleviating green house gas?GHG?emissions and improving forest soil carbon sink.However,management practices,including fertilization,tillage and understory vegetation removal,has caused serious environmental problems of nutrient loss and GHG emissions increase.Thus,it is critically important to investigate soil N₂O emissions from plantation ecosystems to fully understand the global budget of N₂O in the atmosphere.Currently there are many researchers have been concentrated on fabrication of biochar-based functional materials that can improve soil fertility,meet crop nutrient requirements while significantly reduce soil N₂O emissions.However,the effects of biochar-based fertilizer?BF?application on soil N₂O emissions from subtropical plantation soils and their mechanisms still remain unclear.This one-year field trial was conducted in the intensively managed Moso bamboo plantation in the typical subtropical region of Hangzhou,Zhejiang Province,China.The effects of different fertilization?incl.Biochar-based fertilizer,Chemical fertilizer and Biochar-based compound chemical fertilizer?on soil N₂O emissions,temperature,moisture,soil nitrogen and carbon pools,enzyme activity in the Moso bamboo plantation were measured.The relationship between soil N₂O emissions and soil environment factors in Moso bamboo plantation were analysed,and the effects of different fertilization applications on soil N₂O emissions in Moso bamboo plantations and associated mechanisms were revealed.The main research results obtained are as follows:?1?The soil N₂O emissions of Moso bamboo plantation shows a remarkable seasonal change in all treatments?incl.Biochar-based fertilizer,Chemical fertilizer and Biochar-based compound chemical fertilizer?,and the maximum value of soil N₂O emissions is in summer,the minimum value is in winter.And the results also shows that the treatment of BF significantly decreased the annual soil N₂O emissions?P<0.05?,while chemical fertilizer?CF?and biochar-based compound chemical fertilizer?BCF?treatments significantly increased the annual soil N₂O emissions?P<0.05?,as compared to the control treatments.?2?The treatments of different fertilization have no significant effect on the soil moisture,temperature and microbial biomass nitrogen?MBN?in Moso bamboo plantation.The treatment of BF,CF and BCF increased the water soluble organic carbon?WSOC?concentration by 13.3%,4.9%and11%,and increased the microbial biomass carbon?MBC?concentration by 12.0%?6.8%and 8.9%,as compared to the control treatment.The treatment of BF decreased the soil NH₄⁺-N concentration by12.6%,while the treatments of CF and BCF increased soil NH₄⁺-N concentration by 18.9%and 7.7%,as compared to control.Compared to the control treatment,BF treatment decreased the soil NO₃^–-N concentration by 13%,and CF and BCFtreatment increased soil NO₃^–-N concentration by 17%and 10%.The treatment of BF decreased water soluble organic nitrogen?WSON?concentration by 11.8%,while the WSON concentration were significantly increased by 25.3%and 14.2%under the treatments of CF and BCF,as compared to control.?3?The soil enzyme activity of Moso bamboo plantation shows a remarkable seasonal change in all treatments?incl.Control,BF,CF and BCF?,The treatment of BF decreased the urease activity by 13.8%while the treatments of CF and BCF increased soil urease activity by 13.0%and 6.0%,as compared to control treatment.The BF treatment decreased the protease activity by 15.7%,while CF and BCF treatments increased soil protease activity by 14.7%and 9.1%,as compared to control.?4?Under the control treatment,the soil N₂O emissions in Moso bamboo plantation was significantly correlated to the soil temperature,WSOC,WSON,MBN concentration,and urease activity and protease activity?P<0.01?,and the soil N₂O emissionswascorrelated to the MBC,NH₄⁺-N and NO₃^–-N concentration?P<0.05?.In the treatment of BF,CF and BCF,the soil N₂O emissions in Moso bamboo plantation was significantly correlated to the soil temperature,WSON concentration,urease activity and protease activity?P<0.01?,and the soil N₂O emissionswascorrelated toNH₄⁺-N,NO₃^–-N concentration?P<0.05?,while the soil N₂O emissions was no correlated to WSOC and MBC concentration.