孙旭超, 张紫薇, 王若飞, 冯成, 曹凑贵, 王浩, 杨青华, 张学林, 胡权义. 秸秆还田下氮肥水平对秸秆碳固定及土壤有机碳储量的影响[J]. 中国生态农业学报 (中英文), 2024, 32(10): 1−10. DOI: 10.12357/cjea.20240204
引用本文: 孙旭超, 张紫薇, 王若飞, 冯成, 曹凑贵, 王浩, 杨青华, 张学林, 胡权义. 秸秆还田下氮肥水平对秸秆碳固定及土壤有机碳储量的影响[J]. 中国生态农业学报 (中英文), 2024, 32(10): 1−10. DOI: 10.12357/cjea.20240204
SUN X C, ZHANG Z W, WANG R F, FENG C, CAO C G, WANG H, YANG Q H, ZHANG X L, HU Q Y. Effects of nitrogen fertilizer level on straw carbon sequestration and soil organic carbon stock under straw returning[J]. Chinese Journal of Eco-Agriculture, 2024, 32(10): 1−10. DOI: 10.12357/cjea.20240204
Citation: SUN X C, ZHANG Z W, WANG R F, FENG C, CAO C G, WANG H, YANG Q H, ZHANG X L, HU Q Y. Effects of nitrogen fertilizer level on straw carbon sequestration and soil organic carbon stock under straw returning[J]. Chinese Journal of Eco-Agriculture, 2024, 32(10): 1−10. DOI: 10.12357/cjea.20240204

秸秆还田下氮肥水平对秸秆碳固定及土壤有机碳储量的影响

Effects of nitrogen fertilizer level on straw carbon sequestration and soil organic carbon stock under straw returning

  • 摘要: 土壤有机碳(SOC)库在养分循环和缓解全球温室效应方面起重要作用。为了探究氮肥对秸秆碳在土壤中转化以及SOC库的影响, 本研究采用盆栽试验, 向不同施氮水平0 (N0)、120 kg(N) hm−2 (N120)、240 kg(N) hm−2 (N240)、360 kg(N) hm−2 (N360)的稻田土壤中添加13C标记的小麦秸秆, 在水稻成熟后采集土样测定不同碳组分含量以及δ13C值, 并分析土壤微生物群落组成。研究结果显示, 与N0处理相比, N240和N360处理中SOC显著提高了7.8%和7.4%, 全氮显著提高了37.2%和34.3%, 溶解性有机碳显著提高了33.7%和48.6%, 微生物量碳显著提高了97.9%和89.6%; 但土壤碳氮比显著降低了21.6%和20.0%。相比N0处理, N120处理的SOC、全氮、碳氮比和溶解性有机碳并没有显著差异, 但显著提高了微生物量碳的含量。此外, 秸秆还田下施用氮肥使细菌含量显著提高24.7%~55.4%, 真菌含量显著提高18.3%~30.2%, 总磷脂脂肪酸含量18.1%~45.2%。施用氮肥提高了>2000 μm和2000~250 μm团聚体的占比以及轻组颗粒有机碳(fPOC)和微团聚内颗粒有机碳(iPOC)组分的有机碳储量, 同时分别显著增加了fPOC和iPOC组分中δ13C值128.3%~194.8%和105.6%~216.9%。但是在高氮(N360)处理下, 各有机碳组分储量没有持续增加。结构方程表明, 施用氮肥可通过增加溶解性有机碳含量, 增加土壤中fPOC组分中有机碳储量, 或者促进微生物群落活性增加iPOC组分中有机碳储量来提高SOC含量。本研究结果表明, 秸秆还田下施用适量氮肥能够促进秸秆碳向土壤中固定并且增加SOC含量。

     

    Abstract: Soil organic carbon (SOC) plays a critical role in nutrient cycling and mitigating global greenhouse effects. This study aimed to investigate the impact of nitrogen fertilizer on the transformation of straw carbon in soil and its effects on the SOC pool. A pot experiment was conducted using paddy soil with different nitrogen application levels 0, 120 kg(N) hm−2, 240 kg(N) hm−2, 360 kg(N) hm−2, denoted as N0, N120, N240, and N360, respectively. 13C-labeled wheat straw was added to the soil, and samples were collected after rice maturity to measure various carbon fractions, δ13C values, and to analyze soil microbial community composition. The results indicated that, compared to the N0 treatment, SOC in the N240 and N360 treatments increased significantly by 7.8% and 7.4%, respectively. Total nitrogen increased significantly by 37.2% and 34.3%, dissolved organic carbon by 33.7% and 48.6%, and microbial biomass carbon by 97.9% and 89.6%. However, the soil carbon-to-nitrogen ratio decreased significantly by 21.6% and 20.0%, respectively. In the N120 treatment, there were no significant differences in SOC, total nitrogen, carbon-to-nitrogen ratio, or dissolved organic carbon compared to the N0 treatment, but microbial biomass carbon content was significantly higher. Furthermore, nitrogen fertilization under straw returning significantly increased bacterial content by 24.7% to 55.4%, fungal content by 18.3% to 30.2%, and total phospholipid fatty acid content by 18.1% to 45.2%. Nitrogen fertilizer application also increased the proportion of >2000 μm and 2000-250 μm aggregates and the organic carbon stock in the light fraction particulate organic carbon (fPOC) and intra-microaggregate particulate organic carbon (iPOC) fractions. Additionally, the δ13C values in the fPOC and iPOC fractions increased significantly by 128.3% to 194.8% and 105.6% to 216.9%, respectively. However, at the highest nitrogen level 360 kg(N) hm−2, the stock of various organic carbon fractions did not continue to increase. The structural equation indicates that the application of nitrogen fertilizer can improve soil organic carbon content by increasing the dissolved organic carbon content, increasing the organic carbon stock in the fPOC fraction, or promoting microbial activity to increase the organic carbon stock in the iPOC fraction. The results of this study indicate that applying an appropriate amount of nitrogen fertilizer under straw returning can promote straw carbon fixation into the soil and increase soil organic carbon content.

     

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