施用硫酸铵对黄土高原地区不同类型土壤CO<sub>2</sub>释放的影响

孟延; 蔡苗; 师倩云; 周建斌

文章摘要

孟延,蔡苗,师倩云,周建斌.施用硫酸铵对黄土高原地区不同类型土壤CO₂释放的影响[J].农业环境科学学报,2015,34(7):1414-1421.

施用硫酸铵对黄土高原地区不同类型土壤CO₂释放的影响

Effect of Ammonium Sulfate Application on CO₂ Emissions from Four Different Soils in Loess Plateau

投稿时间：2015-01-25

DOI：10.11654/jaes.2015.07.026

中文关键词: 土壤类型碳释放灭菌无机碳矿质态氮土壤pH

英文关键词: soil type carbon emission sterilization inorganic carbon mineral nitrogen soil pH

基金项目:国家自然科学基金项目(31372137);国家“十二五”科技支撑计划课题(2012BAD15B04)

作者	单位	E-mail
孟延	西北农林科技大学资源环境学院, 陕西杨凌 712100 农业部西北植物营养与农业环境重点实验室, 陕西杨凌 712100
蔡苗	西北农林科技大学资源环境学院, 陕西杨凌 712100 农业部西北植物营养与农业环境重点实验室, 陕西杨凌 712100
师倩云	西北农林科技大学资源环境学院, 陕西杨凌 712100 农业部西北植物营养与农业环境重点实验室, 陕西杨凌 712100
周建斌	西北农林科技大学资源环境学院, 陕西杨凌 712100 农业部西北植物营养与农业环境重点实验室, 陕西杨凌 712100	jbzhou@nwsuaf.edu.cn

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中文摘要:

采用密闭培养法研究了未灭菌及灭菌条件下施用硫酸铵对陕西黄土高原地区的四种石灰性土壤(塿土、黑垆土、黄绵土和风沙土)pH值、矿质态氮含量及CO₂ 释放量的影响。结果表明:经过46 d的培养,未灭菌条件下施用硫酸铵后不同土壤CO₂ 释放量相比各不施氮土壤均有所提高,培养结束时塿土、黑垆土、黄绵土和风沙土分别比不施氮各土壤CO₂释放量增加了26.9%、19.5%、68.8% 及 46.1%;采用哌嗪-1,4-二乙磺酸(PIPES)缓冲的HgCl₂溶液灭菌后,培养期间土壤pH值降低幅度小于未灭菌土壤,矿质态氮含量稳定,CO₂ 释放量明显降低,表明灭菌效果良好,有效抑制了土壤有机质矿化及铵态氮的硝化作用。灭菌条件下相比不施氮土壤,施氮后四种土壤CO₂ 累积释放量仍平均增加了25.5%。一方面与硫酸根的存在能导致土壤酸化促进碳酸盐分解有关,另一方面也与土壤溶液的分压作用导致CO₂产生有关,表明石灰性土壤培养过程中释放的CO₂不仅来自有机质,也可来自无机碳。我国西北无机碳储量巨大,应在今后的农业生产中重视生理酸性氮肥对土壤无机碳释放的影响。

英文摘要:

Large emissions of greenhouse gases have caused the global temperature increase. CO₂ is one of the most important greenhouse gases. Calcareous soils are rich in calcium carbonate, which may release CO₂. Soil pH and calcium carbonate content are often deemed to be important factors controlling soil inorganic carbon turnover. Here airtight culture method was adopted to evaluate the role of applying ammonium sulfate[(NH₄)₂SO₄] fertilizer on CO₂ emissions from four different calcareous soils from Loess Plateau. These soils are Lou soil, dark loessial soil, loessial soil and aeolian sandy soil varying in SOM, pH, texture and carbonate content. The soils were incubated under closed-jar conditions for 46 days at 25 ℃with and without 1000 mg·kg^-1 mercury chloride(HgCl₂) buffered by piperazine-1,4-bisethanesulfonic acid(PIPES). Under non-sterilized condition,(NH₄)₂SO₄ application decreased soil pH and NH₄⁺ content. However, sterilization effectively inhibited the nitrification process, thus alleviating soil pH reduction and resulting in NH₄⁺ accumulations in soil. After 46 days of incubation, applying (NH₄)₂SO₄ funder non-sterilized condition increased CO₂ emissions by 26.9%, 19.5%, 68.8% and 46.1% for Lou soil, dark loessial soil, loessial soil, and aeolian sandy soil, respectively, compared to control soils(no fertilization). Sterilization obviously decreased CO₂ releases, implying restrained soil organic mineralization. However,(NH₄)₂SO₄ treatments still increased CO₂ emissions from four sterilized soils by average 25.5% in comparison to no(NH₄)₂SO₄ soils. Our results suggest that the main mechanism for CaCO₃ dissolution was protons produced by nitrification under non-sterilized condition, while it was H₂SO₄ under sterilized conditions. The partial pressure of soil solution might also leads to release of CO₂. Our study confirmed that CO₂ released from calcareous soil during the incubation may be from both soil organic carbon and soil inorganic carbon. Ignoring this inorganic process would result in overestimation of mineralization of soil organic carbon.

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