Effect Of Greenhouse Gas Emission And Analysis Of Soil Benefit By Applying Biochar On The Paddy Field

Biochar, refers to the highly aromatic substance remaining after pyrolysis of biomass undercomplete or Partial exclusion of oxygen. Due to the high stability and high capacity of absorption,biochar became the focus about increasing resources and emission reduction of carbon. Lowutilization rate of agricultural waste and large amount of greenhouse gas emissions from paddyfield were two substantial issues which prevent the sustainable development of agriculture inChina. In this thesis, the detailed analysis of effect of greenhouse gas emission and soil benefit byapplying biochar on the paddy field is presented which aim to provide comprehensive data supportfor the development of new technique on greenhouse gas emission of paddy soil ecosystem andthe new idea about the utilization of agricultural waste which is used by straw carbon. The mainresults of this thesis are as following:The samples were collected and measured by static-chamber and gas chromatograph, and thecharacteristics of CH4emission were studied under the action of different biochar type, applicationamount, returning time and returning depth in the greenhouse. The results showed that the yieldwas significantly increased after different biochar applying, compared with the control treatment,and the highest filled grainweight of BC treatment reached18.12g per pot;CH4emission flux ofBC treatment was significantly higher than that of RC or WC treatment （P<0.05）, however for thelater two, there were no significant differences （P>0.05）; A linear negative correlation was foundbetween CH4emission flux and biochar application amount （r=-0.904, P<0.05）; Meanwhile, CH4emission flux of bamboo carbon applying before rice transplantation (56.6mg m^-2h^-1) was notsignificant lower than those of CK (96mg m^-2h^-1) and before or after rice survival (73.4mg m^-2h^-1and76.6mg m^-2h^-1, P>0.05), which was consistent to the change of soil redox potential （Eh）;In addition, the sequence of CH4emission flux in different biochar returning depth was in theorder of middle inputting<surface inputting<deep inputting<CK, which showed the biocharmiddle inputting was more beneficial to the growth of soil microorganism. It is an effectivemethod to decrease CH4emission by applying biochar on the paddy field.The effects of N₂O emission were studied under the action of different biochar type,application amount, returning time and returning depth in the greenhouse. The results showed thatN₂O emission flux of BC treatment (17.57μg·m^-2·h^-1) was significantly lower than that of RC(21.78μg·m^-2·h^-1) or WC treatment (27.5μg·m^-2·h^-1); A linear negative correlation was foundbetween N₂O emission flux and biochar application amount （r=-0.907, P<0.05）; In addition, N₂Oemission flux of WC treatment after rice survival (34.0μg·m^-2·h^-1) was higher than those of beforerice survival (26.3μg·m^-2·h^-1) or before rice transplantation (21.68μg·m^-2·h^-1), but there were nosignificant differences; Meanwhile, the sequence of N₂O emission flux in different biocharreturning depth was in the order of CK>deep inputting>middle inputting>surface inputting. The study showed it is an effective method to decrease N₂O emission by applying biochar on thepaddy field.The analysis of soil benefits were studied in the greenhouse. The results showed that contrastwith CK, the soil organic matter content of SC treatment respectively increased by12.8%,15.2%,22.4%�'�21.0%（P<0.05）; the content of soil available P and K was higher than CK（P<0.05） afterSC treatment, however, the content of soil available N show a trend which was lower than CK atprophase and close even higher than CK at anaphase; In addition, the yield of lolium plants afterapplying straw carbon with1%、2%and4%were significantly higher than that of CK with aincrease by3.7%、4.8%and3.2%（P<0.05） which indicated the yield of lolium plants wasimproved by applying biochar.