Characteristics And Influential Factors Of Emission Of Green House Gas From Red Soil Under Long-term Fertilization

Soil which is the important part of land ecosystem has the significant role controlling emission of green house gas and global climate change.Red soil is one type of soil in the southern China,which hold the balance of agriculture practice.In order to ascertain the characteristics and influential factors of green house gas emission under long-term fertilization,we collected and incubated the soil of 6 treatment from long-term fertilization(without any fertilization or tillage,CK_O;without any fertilization, CK;nitrogen plus phosphorus plus Potassium,NPK;manure plus NPK,NPKM;NPK plus straw, NPKS;manure,M),measured CO₂ or N₂O emission during incubation and in field,analyzed the correlation between temperature,moisture,biological and chemical character which is effected by long-term fertilization and CO₂ or N₂O emission,ascertained the influential mechanism of long-term fertilization to the green house gas emission in red soil.We hope to supply the academic thereunder about reducing green house gas and modeling the contribution of long-term fertilization for decreasing climate change.The main results and conclusion are given as follows:(1) The mineralization of organic Carbon in red soil under long-term different fertilization is significantly different(P＜0.05).The potential CO₂-C production(C₀) derived from the first-order kinetic model,is 19.3～589.2 mg·kg^-1.The pattern is CK_O＞M＞NPKM＞NPK≈NPKS＞CK.The production of CO₂ is increased by the use of chemical fertilizer and manure. The effect of manure is higher than chemical fertilizer's.The productive rate of CO₂-C(1.7～163.4 mg·m^-2·h^-1) measured in field is similar to that of incubation.The rate of M,CK_O and NPKM is significantly greater than that of NPKS,CK and NPK(P＜0.05).(2) The mineralization of organic Carbon during incubation with different temperature and moisture varies significantly(P＜0.01):the higher the temperature is,the greater the rate and the accumulate production is;the mineralization of organic Carbon is increasing with the higher moisture.During incubation,soil temperature has significant effect on C₀(P＜0.05). The result modeled by linear and exponential equation shows that the response of C₀ under different fertilization to temperature varies,the response of CK_O and M is greater.(3) The use of manure can significantly increase the account of microbe(P＜0.01).The increasing account of microbe which is later than the change of mineralization rate,its activity is low when the mineralization rate gets the peak.However,the amount of microbe is significantly correlative with those of mineralization after the 14^th day of incubation(P＜0.05). Average well color development(AWCD) and the diversity value(H') of the soil with manure is greater.The integrative value of principal Component Analysis(F) under different fertility varies,the pattern is CK_O＞M＞NPKM＞CK＞NPKS＞NPK,which is similar to that of C₀.Long-term fertilization has significant effect on the microbial communities.That of the treatment under manure and chemical fertilization is obviously different.Long-term fertilization has significant effect on the Carbon composition.Microbial Carbon,total organic Carbon,soluble organic Carbon of siol with manure is greater,which is significantly correlative with C₀(P＜0.05).During incubation,the cost of microbial Carbon is corresponding to the changing rate of the mineralization of organic Carbon.The production of CO₂ during incubation may come from the microbial Carbon mostly.The result of regression and pathway shows that the influential factors of C₀ as following as:dissolved organic Carbon＞microbial Carbon＞pH value＞alkali dispelled Nitrogen＞total Nitrogen.The direct effect of dissolved organic Carbon is greater than microbial Carbon.Other factors,like pH value and alkali dispelled Nitrogen has effect on microbial Carbon,and then effect on C₀.(4) Long-term fertilization has significant effect on the emission of N₂O(P＜0.05).The sample with the use of chemic fertilization(NPK) has the highest production of N₂O(2.8～3.4 mg·kg^-1) during the incubation of 30 days.The N₂O production of M and NPKM is 1.4～1.9 mg·kg^-1,1.1～1.7 mg·kg^-1.The use of organic-Nitrogen has effect on that,but it is significantly lower than chemic fertilization(urea).The productive rate of N₂O is greater when the soil moisture is higher.The production of N₂O with the moisture of 95%of field water- holding capacity(FWHC) is significantly higher than which of 55%FWHC and 75%FWHC(P＜0.05).The total Nitrogen and total organic is not significantly correlative with production of N₂O,but the ratio of Carbon and Nitrogen is significantly negative correlative with it(P＜0.01).Alkali dispelled Nitrogen,NH₄⁺-N and NO₃^--N is significantly positive correlative with it(P＜0.01).The negative correlation between pH value and production of N₂O is significant (P＜0.01).(5) The productive rate of CO₂-C and N₂O measured in field is almost similar to that of incubation.The productive rate of CO₂-C is 1.7～163.4 mg·m^-2·h^-1,that of M,CK_O and NPKM is significantly greater than that of NPKS,CK and NPK(P＜0.05).The rate of CO₂-C in the soil with root is greater than that without root.The variation of CK_O and M is great.The rate of N₂O of NPKS and NPK is greater than others'.The moisture measured in field is significantly correlative with the productive rate of CO₂-C(P＜0.05),yet the effect of soil temperature is small.The productive rate of CO₂-C is significantly linearly correlated with soil moisture(P＜0.05).The slope of M,CK_O and NPKM is greater,whose response to soil moisture is strong.The productive rate of N₂O is significantly linearly correlated with soil temperature and moisture(P＜0.05).However,the result of stepwise regression shows that soil moisture is the direct factor which has effect on the productive rate of CO₂-C and N₂O,but the effect of soil temperature is little.To sum up,the long-term use of manure has significant effect on the emission of CO₂ from mineralization of organic Carbon;the use of chemic fertilization significantly increases the production of N₂O,yet the same amount of organic-N have smaller effect on it.Besise siol temperature and moisture, the amount of microbe,microbial communities,total organic Carbon,microbial Carbon,dissolved organic Carbon,the ratio of Carbon and Nitrogen,total Nitrogen,Alkali dispelled Nitrogen and pH value which is influenced by long-term fertilization,is significantly correlative with the production of green house gas.They practise as referent to track and forecast the variation of organic mineralization and accumulation and the production of green house gas,it has essential sense to supervise fertilization and controlling the environmental change.