Study On The Characteristics Of Greenhouse Gas Emission From Wheat And Maize By Biochar And Nitrification Inhibitors

In recent years,due to N2O,CH4 and CO2 and other three kinds of greenhouse gas emissions increased year by year,leading to global warming and other environmental degradation has been a global concern,become today's research focus.Agroecosystem,as an important source of emissions,is most affected by human activities.(CK),traditional fertilization(TO),urea and biochar(T1),urea and DMPP(T2)and foliar spray(T3)were set up in the Jianghuai area.And the annual greenhouse gas emission of wheat and maize was measured by static dark box-gas chromatography.The total greenhouse gas emission was calculated and the comprehensive greenhouse effect and greenhouse gas intensity under 5 treatments were estimated.The main results and conclusions are as follows.The results showed that the N2O emission was similar to that of CK,and the N2O emission rate of CK was gentle and no peak appeared.Wheat season TO,T1,T2 and T3 treatment After top dressing and rain,the N2O emission rate peaked and no peak was found after basal fertilizer.The total N2O emissions from T0,T1,T2 and T3 treatments were 29.90%,36.88%,27.90%and 29.88%of the total growth period 15 days after topdressing.Compared with T0 treatment,the total N2O emissions from T1 and T2 treatment Decreased by about 25.09%and 46.07%,reaching a significant level(P<0.05),while T3 treatment increased by about 1.50%.In the maize season,we found that the T0,T1,T2 and T3 treatments were peaked after fertilization and topdressing,and the emission peaks at T1,T2 and T3 were lower than the T0 treated emission peak 680.04 ?gN·m-2·hr-1,755.33 ?g N·m-12·hr-1,30.11 ?gN·m-2·hr-1 and 260.12 ?gN·m-2·hr-1,323.27 ?gN·m-2·hr-1,3.38 ?gN·m-2·hr-1.And T1,T2 and T3 treatments were about 64.01%,70.70%and 9.87%lower than those of T0,respectively(P<0.05).During the observation period,CH4 emissions were not detected on December 9,December 15,2015,and July 18 and July 20,2015,and no CH4 absorption was observed throughout the growth period.The average annual emission rate of CK,T0,T1,T2 and T3 in wheat season was 0.26 mg C·m-2·hr-1,0.34 mg C·m-2·hr-1,0.25 mg C·m-2·hr-1,0.36 mg C·m-2·hr-1 and 0.36 mg C·m-2·hr-1,respectively,and the average emission rate in the maize season was 0.59 mg M-2·hr-1,0.36 mg C·m-2·hr-1,0.48 mg C·m-2·hr-1,0.42 mg C·m-2·hr-1 and 0.37 mg-2·hr-1.Compared with TO treatment,the total CH4 emissions from T1 treatment decreased by 25.92%,while the total CH4 emissions from T2 and T3 increased by 5.16%and 5.57%respectively.The treatments of T1,T2 and T3 were higher than those of T0.The total CH4 emissions increased by 31.84%,16.69%and 3.23%respectively.The results showed that the CO2 emission trends of the two treatments were basically the same.The rate of CO2emissions from CK,T0,T1,T2 and T3 treatments in wheat season remained flat before March 4,and then the emission rate increased gradually and reached the peak of discharge on April 8,respectively,at 261.00 mg C·m-2 Hr-1,297.86 mg C·m-2·hr-1,304.86 mg C·m-2·hr-1,254.02 mg C·m-2.hr-1 and 313.60 mg C·m-1·hr-1,and then gradually decreased,the total amount of CO2 emissions during the winter period accounted for only 11.47%,11.52%,9.56%,11.43%and 11.53%of the whole growth period respectively.Compared to T0 treatment,the total CO2 emissions from T1 and T3 increased by 5.05%and 10.53%,and the total CO2 emissions from T2 treatment decreased by 5.18%.The emission rates of CO2,CK,T0,T1,T2 and T3 in the maize season showed a trend of increasing first and then decreasing,and reached the emission peak on August 7 and 10,respectively,which was 307.00 mg C·m-2·hr-1,328.54 mg C·m-2·hr-1,334.69 mg C·m-2·hr-1,281.42 mg C·m-2·hr-1 and 253.97 mg C-m-2·hr-1.Compared with T0 treatment,the total CO2 emissions from T1,T2 and T3 decreased by about 13.36%,19.01%and 5.35%,respectively(P<0.05).The results showed that the treatments of T1,T2 and T3 treatments increased by 9.8%,8.53%and 12.43%,respectively,and the treatments of T1 and T2 treatments increased by 11.80%and 15.1 7%compared with T0 treatments,while the treatments decreased 1.29%.The results showed that the addition of biochar and DMPP improved nitrogen use efficiency and nitrogen partial productivity.The addition of biochar treatment not only reduces the comprehensive greenhouse effect of wheat and maize,but also improves the soil physical and chemical properties compared with T0 treatment.(P<0.05),the content of total nitrogen,total phosphorus and total potassium was higher than that of T0 treatment(P<0.05),and the content of total nitrogen,total phosphorus and total potassium was higher than that of T0 treatment(P<0.05)The soil bulk density decreased by 0.02 g·kg-1 and 0.03 g·kg-1,3.0 g·kg-1,respectively.