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农田土壤已成为大气氧化亚氮(N2O)最大的人为释放源,为了解长期有机肥与无机肥配施对后茬作物土壤N2O排放的影响,本研究基于宁夏河套地区典型冬小麦-油葵复种农田生态系统,利用静态箱-气相色谱法对后茬作物(油葵)种植期内土壤N2O通量特征进行了测定.结果表明:前茬施肥对后茬油葵土壤N2O排放具有显著的刺激效应,N300-OM(210kg N·hm-2无机肥、90 kg N·hm-2有机肥)、N240-OM1/2(195 kg N·hm-2无机肥、45 kg N·hm-2有机肥)、N300(300 kg N·hm-2无机肥)和N240(240 kg N·hm-2无机肥)处理下土壤N2O生长季平均通量为(34.16!9.72)、(39.69!10.70)、(27.75!9.57)和(26.31!8.52)μg·m-2·h-1,分别是对照样地的4.09、4.75、3.32、3.15倍.施肥处理下油葵生长季内N2O总累积排放量高达1242.5~796.7 g·hm-2,是对照组的4.67~2.99倍;在整个生长季,有机肥与无机肥配施处理N2O排放速率都维持在较高水平,各月累积排放量间无显著差异;而单施化肥处理N2O排放速率逐渐下降,生长季初期为主要排放阶段,7月累积排放量占总排放量的41.3%~41.8%;不同施肥方式下,有机肥与无机肥配施处理N2O总累积排放量显著高于单施化肥,但相同施肥方式下高氮量处理与减氮优化处理(N300-OM与N240-OM1/2,N300与N240)间差异不显著.受干旱影响,土壤水分是控制油葵田土壤N2O排放的主要环境因素.有机肥与无机肥配施处理下N2O排放速率与NH4+-N含量呈显著正相关,而所有处理下N2O排放速率与土壤NO3--N含量均不相关,表明添加有机肥会持续改善土壤NH4+-N供给进而增加N2O排放.
Cropland soil has become the largest anthropogenic release source of atmospheric N2O. In order to understand the effect of long-term organic fertilizer and inorganic fertilizer on the N2O emission of the following crop plants, this study was based on the typical winter wheat-sunflower multiple cropland Ecosystem, the characteristics of soil N2O flux in the following crop (sunflower) planting period were measured by static box-gas chromatography.The results showed that: the former stubble fertilization had a significant stimulating effect on the N2O emission of the late crop oil sunflower soils, N300-OM (210 kg N · hm-2 inorganic fertilizer, 90 kg N · hm-2 organic fertilizer), N240-OM1 / 2 (195 kg N · hm-2 inorganic fertilizer, 45 kg N · hm-2 organic fertilizer) , N300 (300 kg N · hm-2 inorganic fertilizers) and N240 (240 kg N · hm-2 inorganic fertilizers), the mean fluxes of soil N2O during the growing season were (34.16 ± 9.72), (39.69 ± 10.70) 9.57) and (26.31! 8.52) μg · m-2 · h-1, respectively, which were 4.09, 4.75, 3.32 and 3.15 times higher than that of the control plots respectively.The total N2O emission of oil sunflower during the growing season was as high as 1242.5 ~ 796.7 g · hm-2, which was 4.67 ~ 2.99 times of that in the control group. During the whole growing season, the N2O emission rate of organic manure and inorganic manure was maintained at a relatively high level, While the N2O emission rate decreased with the single application of chemical fertilizers, with the main discharge stage in the early growing season, and the accumulated emissions in July accounted for 41.3% -41.8% of the total emissions. In different fertilization modes, the combination of organic manure and inorganic fertilizer The total N2O emission was significantly higher than that of single application of chemical fertilizer, but there was no significant difference between high N treatment and N3 optimization (N300-OM and N240-OM1 / 2, N300 and N240) under the same fertilization mode.Drought affected by drought, Soil moisture was the main environmental factor controlling the N2O emission from the oilfields.N2O emission rate was significantly and positively correlated with NH4 + -N content under organic and inorganic fertilizer treatments, but the N2O emission rate was positively correlated with NO3 - N Content are not related, indicating that the addition of organic fertilizer will continue to improve soil NH4 + -N supply and thus increase N2O emissions.