不同水分对荒地和开垦农田黑土氮素转化和温室气体排放的影响

郎漫; 韦诗靖; 韦少华; 李冬凌; 李平

文章摘要

郎漫,韦诗靖,韦少华,李冬凌,李平.不同水分对荒地和开垦农田黑土氮素转化和温室气体排放的影响[J].农业环境科学学报,2026,45(3):786-795.

不同水分对荒地和开垦农田黑土氮素转化和温室气体排放的影响

Effects of different moisture contents on nitrogen transformation and greenhouse gas emissions from uncultivated and cultivated cropland black soil

投稿时间：2025-03-28

DOI：10.11654/jaes.2025-0301

中文关键词: 土壤水分农业管理黑土 N₂O CO₂ 氮转化

英文关键词: soil moisture agricultural management black soil N₂O CO₂ nitrogen transformation

基金项目:中央土壤污染防治资金项目（新集采单〔2021〕1468）

作者	单位	E-mail
郎漫	南京信息工程大学, 农业与生态气象江苏省高校重点实验室, 南京 210044 南京信息工程大学生态与应用气象学院, 南京 210044
韦诗靖	南京信息工程大学生态与应用气象学院, 南京 210044
韦少华	南京信息工程大学生态与应用气象学院, 南京 210044
李冬凌	南京信息工程大学生态与应用气象学院, 南京 210044
李平	南京信息工程大学, 农业与生态气象江苏省高校重点实验室, 南京 210044 南京信息工程大学生态与应用气象学院, 南京 210044	pli@nuist.edu.cn

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中文摘要:

为探讨不同水分条件下黑土氮素转化和温室气体排放规律，以荒地和开垦农田黑土为对象，在25℃和不同水分条件[60%最大持水量（WHC）和90% WHC]下进行7 d培养试验，研究土壤中无机氮含量的变化及CO₂和N₂O的动态排放。结果表明，黑土开垦后净氮矿化速率显著下降，而净硝化速率显著增加（P<0.05），水分含量变化对荒地土壤和开垦土壤的净氮转化速率都没有显著影响（P>0.05）。两种水分条件下，荒地土壤的CO₂排放速率都显著高于开垦土壤（P<0.05）。水分含量变化对CO₂排放速率的影响取决于土地利用方式，当土壤水分从60% WHC增加到90% WHC时，荒地土壤的CO₂排放速率显著降低，培养期间CO₂累积排放量从82.52 mg·kg^-1显著下降到69.32 mg·kg^-1（P<0.05），而开垦土壤在60% WHC和90% WHC条件下的CO₂排放速率相当，CO₂累积排放量分别为57.62 mg·kg^-1和59.18 mg·kg^-1，两者之间没有显著差异（P>0.05）。土地利用方式和水分含量对N₂O排放具有显著影响，两者之间存在交互作用（P<0.001）。在60% WHC水分条件下，开垦土壤的N₂O排放速率显著高于荒地土壤（P<0.05），其累积排放量（4.20 μg·kg^-1）是荒地土壤（2.90 μg·kg^-1）的1.45倍。而在90% WHC水分条件下，荒地土壤的N₂O排放速率显著高于开垦土壤（P<0.01），其累积排放量（1 280.4 μg·kg^-1）是开垦土壤（279.9 μg·kg^-1）的4.57倍。在60% WHC水分条件下，荒地土壤和开垦土壤的N₂O排放比例在0.013%~0.041%之间，表明N₂O主要来自硝化过程。在90% WHC水分条件下，荒地土壤的N₂O排放比例介于4.03%~10.00%之间，开垦土壤的N₂O排放比例介于0.021%~1.148%之间，表明N₂O主要来自反硝化过程。研究表明，长期开垦可以导致黑土pH和有机碳含量下降，使得微生物呼吸释放的CO₂减少，氮矿化能力降低，而氮肥的大量施用可促进硝化作用的发生和好气条件下N₂O的排放，但在水分含量相对较高时，N₂O排放量可能低于荒地土壤。

英文摘要:

This study aimed at exploring the regularity of N transformation and greenhouse gas emissions from black soils under different moisture contents. A laboratory incubation experiment was conducted under 25 ℃ and 60%WHC or 90%WHC for 7 days to study the dynamic changes of inorganic N contents and the emissions of N₂O and CO₂ from uncultivated and cultivated cropland black soil. The results showed that the net N mineralization rate of black soil was significantly decreased after soil was cultivated, while the net nitrification rate was significantly increased（P<0.05）, the changes of soil moisture content had no effect on net N transformation rates for both soils（P> 0.05）. The CO₂ emission rate of the uncultivated soil was significantly higher than that of the cultivated soil（P<0.05）, regardless of the soil moisture content, while the soil moisture effects on CO₂ emission were depended on land-use type. When the moisture content in uncultivated soil increased from 60%WHC to 90%WHC, the CO₂ emission was inhibited significantly, with the CO₂ cumulative emission decreased from 82.52 mg·kg^-1 to 69.32 mg·kg^-1（P<0.05）, while the CO₂ emission rates of cultivated soil under 60%WHC and 90%WHC were comparable, and no significant difference（P>0.05）was found for the CO₂ cumulative emissions under the two moisture contents （57.62 mg·kg^-1 and 59.18 mg·kg^-1, respectively）. Land-use type, moisture content, and their interactions had significant effects on N₂O emissions from soil（P<0.001）. The N₂O emission rate of cultivated soil under 60%WHC was significantly higher than that of uncultivated soil（P<0.05）, with the N₂O cumulative emission（4.20 μg·kg^-1）was 1.45 times that of uncultivated soil（2.90 μg·kg^-1）. The reverse was true when soil was incubated under 90%WHC, with the N₂O cumulative emission of uncultivated soil（1 280.4 μg·kg^-1）was 4.57 times that of cultivated soil（279.9 μg·kg^-1）. Under the conditions of 60%WHC, N₂O emission ratio of uncultivated and cultivated soils were between 0.013%-0.041%, indicating that N₂O was mainly emitted from nitrification process. Under the conditions of 90%WHC, N₂O emission ratio of uncultivated and cultivated soil were between 4.03%-10.00% and 0.021%-1.148%, respectively, indicating that N₂O was mainly emitted from denitrification process. Our results indicated that long-term cultivation could lead to the decrease of pH and organic C content in black soil, thereby reducing the CO₂ emission from microbial respiration and the ability of N mineralization. The large application of N fertilizer could promote the occurrence of nitrification and N₂O emission under aerobic conditions, but when the water content increased, N₂O emission maybe lower than that of uncultivated soil.

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