Mineral N suppressed priming effect while increasing microbial C use efficiency and N2O production in sandy soils under long-term conservation management
Mineral N suppressed priming effect while increasing microbial C use efficiency and N2O production in sandy soils under long-term conservation management
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DOI：
10.1007/s00374-022-01665-6
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发表时间：
2022-09
影响因子：
6.5
通讯作者：
Binaya Parajuli;R. Ye;A. Szogi
中科院分区：
文献类型：
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作者：
Binaya Parajuli;R. Ye;A. Szogi
秸秆还田恢复土壤有机碳是土壤健康管理的重要组成部分。在本研究中，我们研究了残留物改良剂和矿质氮(N)添加对沙质Ultisols中添加的残留物和SOC保存的交互影响。土壤样品采集自长期减少耕作的农田，并与13C标记的作物残留物硝酸铵(NH4NO3)或两者同时孵化，或不与其孵化55天。呼吸作用、微生物量碳、酶活性和碳利用效率(CUE)与一氧化二氮(N2O)的产生一起被测量。在培养结束时，残留物改良剂使CO2产量增加了206%，产生了正启动效应(PE)。矿质氮降低了残留物改良剂对CO2产量和PE的积极影响，导致微生物线索较高。然而，N的添加对有机C反应所涉及的酶活性没有影响，除了在残留物存在时β-葡萄糖苷酶的活性。在试验结束时，添加矿质氮可使残渣分解减少89%。总CO_2(R2= − 0.56)、残留物衍生CO_2(R2= − _(0.62))、有机碳衍生CO_2(R2= − _(0.53))和固定生产量(R2= − _(0.52))均与土壤NH_4~+浓度呈负相关。残留物改良剂立即刺激N2O的产生，矿质氮的添加增加了N2O的产生。反硝化作用似乎是产生N2O的主要途径。这一结果进一步证实了氮素通过直接和间接影响土壤微生物活动来调节土壤有机碳动态的观点。氮肥与残留物管理相结合似乎有望提高沙质土壤中有机碳的稳定性和保持性。然而，需要考虑N2O生产的权衡。
Restoring soil organic carbon (SOC) with residue incorporation is an important component of soil health management. In the present study, we investigated the interactive impacts of residue amendment and mineral nitrogen (N) additions on preserving the added residues and SOC in a sandy Ultisols. Soil samples were collected from fields under long-term reduced tillage and incubated with either13C-labelled crop residues, ammonium nitrate (NH4NO3), both, or neither for 55 days. Respiration, microbial biomass C, enzyme activities, and C use efficiency (CUE) were measured along with nitrous oxide (N2O) production. Residue amendment increased CO2production by 206% at the end of the incubation, inducing positive priming effects (PE). Mineral N reduced the positive impacts of residue amendment on CO2production and PE, resulting in higher microbial CUE. However, the N addition had no effects on the measured enzyme activities involved in organic C reactions, except for β-glucosidase activity when residues were present. Additions of mineral N reduced residue decomposition by 89% at the end of the experiment. Total CO2(R2= − 0.56), residue-derived CO2(R2= − 0.62), SOC-derived CO2(R2= − 0.53), and the primed production (R2= − 0.52) were all negatively correlated to soil NH4+concentrations. Residue amendment instantly stimulated N2O production, which was augmented by mineral N addition. Denitrification was seemingly the main N2O production pathway. The results reinforced the concept that N can regulate SOC dynamics through direct and indirect impacts on soil microbial activities. Combining N fertilization and residue management is seemingly promising to increase SOC stability and preservation in sandy soils. However, the trade-offs of N2O production need to be considered.