长期施肥下红壤旱地CO_2、N_2O排放特征

CO_2、N_2O Emission from Red Soil Dry-land under Long-term Fertilization

通过研究长期不同施肥处理对红壤旱地农田土壤温室气体排放的影响,以期为南方红壤旱地农田生态系统土壤碳氮循环机制、环境气体减排和南方红壤旱地农田生态系统CO2、N2O排放量估算提供科学依据;基于中国农业科学院红壤实验站长期定位试验,采用静态箱/气相色谱法,研究红壤旱地小麦生长季节不同施肥处理(CK、NP、NPK、NPKM、1.5NPKM)下土壤CO2、N2O排放差异;结果表明:在小麦生长季,不同施肥处理之间土壤呼吸CO2、N2O排放通量差异显著,土壤呼吸CO2年累积排放量在8284.02～15863.48kg/hm2之间,N2O年累积排放量在0.37～2.04kg/hm2之间;各处理土壤呼吸CO2排放通量的大小变化:1.5NPKM>NPKM>NPK>CK>NP;土壤呼吸N2O平均排放通量大小顺序为1.5NPKM>NPKM>NPK>NP>CK;土壤呼吸CO2与N2O排放分别与土壤温度和土壤水分呈现显著相关性(P<0.05)。所以得出以下结论:长期不同施肥处理后形成的土壤肥力以及作物生长的差异是影响土壤呼吸CO2、N2O排放的重要因素;红壤旱地小麦季土壤呼吸CO2、N2O排放具有明显的季节变化特征;土壤CO2排放主要集中在作物的拔节期和休闲期,有机肥的配合施用在提升红壤旱地肥力、维持红壤旱地可持续发展的同时,也显著增加了土壤呼吸CO2和N2O的排放。

By studying the effect of different patterns of long-term fertilization on greenhouse gas emissions of red soil in dryland agricultural soils, in order to provide a scientific basis for soil carbon and nitrogen cycle mechanism of dry-land ecosystem of red soil in south China, the reduction of greenhouse gases emission, and estimation of CO2, N2O emission of dry-land ecosystem of red soil in south China. Diurnal variation of soil respi- ration affected by long-term different fertilization at various growth stages of wheat in red soil dry-land was investigated with the static dark chamber method and gas chromatograph technique in the Experimental station of red soil CAAS; Results show that CO2, N2O emission fluxes in different experimental treatments had significant differences Cumulative emissions of CO2 and N2O in the year varying in the range of 8284.02 -15863.48 kg/ hm^2 and 0.37-2.04 kg/hm^2. In terms of the effect of fertilization, the CO2 emissions followed an order of 1.5NPKM〉NPKM〉NPK〉CK〉NP, and N2O emissions followed an order of 1.5NPKM〉NPKM〉NPK〉NP〉CK, The treatment with organic manure increase in CO2 and N2O emissions significantly （P〈0.05） than the others. The change of C02 emissions was obviously related to soil temperature, but the change of N2O emissions was obviously related to soil water content. So we concluded that the different soil fertility and crop growth under long-term different fertilization is an important factor to affect the soil CO2, N2O emissions; during the growth stages of wheat, soil respiration rate displayed an obvious seasonal curve. The emission of CO2 was concentration on jointing stage and fallow period. The application of organic manure could improve the fertility of dry-land red soil, and maintained sustainable development of dry-land red soil, while the application of organic manure increased the soil respiration of CO2 and N2O emissions significantly.