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土体呼吸输出碳来源于土壤固有有机碳和外源添加碳,而以往关于不同施肥措施对水稻土碳排放的研究少有区分碳的来源。本试验利用一个长达30年的水稻土定位试验,在保证原有定位试验继续正常开展的前提下变更部分施肥处理,得到继续施用高量有机肥(HOM)、施用常量有机肥30年后改施高量有机肥(N-H)、继续施用常量有机肥(NOM)、施用化肥30年后改施常量有机肥(C-N)、施用高量有机肥30年后改施化肥(H-C)、施用常量有机肥30年后改施化肥(N-C)、继续施用化肥(CF)等7种施肥处理。通过观测早稻生长期间原有施肥和改施肥处理土体CO2排放通量(FCO2),研究不同后续施肥对水稻土FCO2的影响,以期探讨土壤原始有机碳和外源添加碳对土壤FCO2的影响。结果表明:7种不同施肥处理土体CO2平均排放通量(F珔CO2)分别为85.34、69.10、51.27、49.15、14.89、12.92和11.59 mg C.m-2.h-1;对施用无机肥料和常量有机肥料的土体而言,土壤本身有机碳含量对F珔CO2无显著影响,但对施用高量有机肥的土体而言,土壤本身的高有机碳含量会增强F珔CO2;CO2排放通量(Y)与添加外源碳量(x)之间符合指数方程:Y=13.33e1.719 x(R2=0.967,n=21),施入的外源有机碳对土体FCO2产生极显著影响;当季外源添加碳以CO2-C矿化分解释放的碳占其总碳量的14%左右,且该分解率受土壤有机碳含量和有机物料添加量的影响较小。
Soil respiration output carbon comes from soil organic carbon and exogenous added carbon. However, previous studies on carbon emissions from paddy soil under different fertilization measures seldom distinguish carbon sources. In this experiment, we used a 30-year paddy soil location experiment to change part of the fertilization treatment under the precondition of ensuring the original location test continued to be carried out normally. The application of high organic fertilizer (HOM) Applying constant amount of organic fertilizer (NH), applying continuous organic fertilizer (NOM), applying constant amount of organic fertilizer (CN) after 30 years of applying chemical fertilizer, reusing chemical fertilizer (HC) after applying high amount of organic fertilizer for 30 years, Fertilizer 30 years after the conversion of fertilizer (NC), continue to use fertilizers (CF) and other seven kinds of fertilizer treatment. The effects of different fertilization treatments on FCO2 in paddy soils were studied by observing the FCO2 fluxes of fertilized and fertilized soils during early rice growth so as to investigate the effects of soil source organic carbon and exogenous carbon on soil FCO2. The results showed that the average fluxes of F CO2 in the seven fertilization treatments were 85.34, 69.10, 51.27, 49.15, 14.89, 12.92 and 11.59 mg Cm-2.h-1, respectively. Organic manure soil organic carbon content had no significant effect on F 珔 CO2, but the high organic carbon content of the soil itself would enhance F 珔 CO2; the CO2 emission through The exponential equation between the quantity (Y) and the exogenous carbon (x) was Y = 13.33e1.719 x (R2 = 0.967, n = 21) The carbon released by exogenous CO to CO2-C mineralization accounted for about 14% of the total carbon, and the decomposition rate was less affected by soil organic carbon content and organic material addition.