| 添加葡萄糖对红壤农田肥料氮转化及其酸化的影响 |
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| 引用本文： | 李九玉,邓开英,章威,桑存星,赵悦彤,徐仁扣.添加葡萄糖对红壤农田肥料氮转化及其酸化的影响[J].土壤学报,2021,58(1):162-168. |
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| 作者姓名： | 李九玉 邓开英 章威 桑存星 赵悦彤 徐仁扣 |
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| 作者单位： | 土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所), 南京 210008;南京林业大学生物与环境学院, 南京 210037 |
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| 基金项目： | 国家自然科学基金项目（41878102）、中国科学院创新交叉团队和创新促进会项目（2014272）资助 |
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| 摘 要： | 采用室内培养实验,初步研究了外加葡萄糖对红壤肥料氮素转化及其酸化作用的影响,其中葡萄糖添加量充足,为8 g·kg–1干土,氮肥以(NH4)2SO4和KNO3为例。结果表明,在对照、单施(NH4)2SO4或KNO3处理中,土壤中氮转化过程主要以有机氮净矿化和铵态氮净硝化为主,这主要是由于红壤可利用碳源较少。而外加足够葡萄糖碳源可快速(2 d内)促进土壤及其100 mg·kg–1氮肥中的NH4+-N和NO3--N几乎全部被微生物同化,30 d培养期间微生物同化促进28%~50%的肥料氮迅速转化为固相有机态氮。单施(NH4)2SO4或KNO3主要通过硝化作用和盐效应降低土壤pH,但微生物对NH4+-N的生物固定可抑制其硝化导致的酸化作用,而微生物对NO3--N的生物固定可提高土壤pH高达0.78个单位。因此,添加葡萄糖等碳源可促进农田土壤中NH4+-N和NO3--N的微生物同化,缓解氮肥引起的土壤酸化作用。研究结果对提高农田土壤的保氮能力和氮肥利用率、抑制土壤酸化等具有重要意义。
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| 关 键 词： | 葡萄糖 硝化作用 微生物同化 土壤酸化 红壤 |
| 收稿时间： | 2019/7/19 0:00:00 |
| 修稿时间： | 2019/9/25 0:00:00 |
Effects of Amendment of Glucose on Fertilizer Nitrogen Transformation and Acidification in Ultisol Cropland |
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| LI Jiuyu,DENG Kaiying,ZHANG Wei,SANG Cunxing,ZHAO Yuetong,XU Renkou.Effects of Amendment of Glucose on Fertilizer Nitrogen Transformation and Acidification in Ultisol Cropland[J].Acta Pedologica Sinica,2021,58(1):162-168. |
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| Authors: | LI Jiuyu DENG Kaiying ZHANG Wei SANG Cunxing ZHAO Yuetong XU Renkou |
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| Institution: | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China;College of Biology and Environment, Nanjing Forest University, Nanjing 210037, China |
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| Abstract: | 【Objective】Soil acidification intensifies extensively in cropland due to anthropogenic activities,thus restraining sustainable development of agriculture on the soil and affecting environmental safety.Long-term excessive application of ammonium nitrogen fertilizer results in strong nitrification,and intensive leaching of nitrate accompanied with base cations,which are the main mechanisms of soil acidification in cropland.However,so far little has been reported in the literature on effective methods to exert source control over soil acidification triggered by nitrogen fertilizer application.It has been reported that amendment of readily utilizable carbon sources,such as glucose and sucrose,can promote microbial assimilation of soil inorganic nitrogen and reduce N mineralization and nitrification in forest soils.Based on the relationship of nitrogen transformation and proton flux,this type of organic-carbon-promoted microbial assimilation of inorganic nitrogen could also retard N-fertilizationinduced soil acidification.Does the amendment of this type of readily utilizable carbon sources also have the effect of controlling or retarding nitrogen transformation and soil acidification in cropland?This question deserves further investigation.【Method】For this study,an in-door incubation experiment was carried out to explore effects of extraneous carbon on N transformation and soil acidification.Glucose was amended as model carbon source at a rate of 8 g·kg-1,and(NH4)2SO4 or KNO3 applied as model nitrogen fertilizer at a rate of 100 mg·kg–1.【Result】Results show that in the treatments of CK,application of(NH4)2SO4and application of KNO3 only,net mineralization of organic N and nitrification of ammonia N dominated the process of N transformation in the soil,which is attributed mainly to the lack of usable carbon sources in Ultisol.Amendment of adequate glucose as extraneous carbon source promoted rapid microbial assimilation of almost all the NH4+-N and NO3--N native in the soil and amended in the form of fertilizer within 2 days.Within 30 days of incubation,N microbial assimilation quickly transformed 28%~50%of fertilizer N into solid organic N.However,application of glucose might trigger the risk of N loss through denitrification.Change in soil pH was closely related to chemical reaction of chemical fertilizer on the surface of the soil and transformation of C and N in the cropland.Application of(NH4)2SO4or KNO3alone lowered soil pH through nitrification and salt effect.Decomposition of glucose generated some mid products like organic acids,such as lactic acid,pyruvic acid,citric acid,etc.,thus lowering soil pH.However,these organic acids consumed protons when decarboxylating,thus neutralizing soil acidity.Addition of glucose induced microbial assimilation or fixation of NH4+-N and NO3-,thus inhibiting NH4+-N-nitrification-triggered soil acidification,which could raise soil pH by up to 0.78.【Conclusion】Consequently,amendment of extraneous readily utilizable carbon sources,such as glucose,can promote microbial assimilation of NH4+-N and NO3--N in the soil and mitigate the soil acidification induced by N transformation in the cropland.All the findings in this study are of important significance for building up soil N retention capacity,improving N fertilizer use efficiency,and inhibiting soil acidification in croplands of acid soil. |
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| Keywords: | Glucose Nitrification Microbial assimilation Soil acidification Ultisol |
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