施用石灰与钙蒙脱石对酸性土壤硝化动力学过程的影响

王梅; 蒋先军

文章摘要

施用石灰与钙蒙脱石对酸性土壤硝化动力学过程的影响

Effects of Applying Lime and CalciumMontmorillonite on Nitrification Dynamics in Acidic Soil

投稿时间：2016-09-18

DOI：10.13254/j.jare.2016.0226

中文关键词: 土壤酸化，净硝化速率，酸性土壤改良

英文关键词: soil acidification, net nitrification rates, acidic soil improvement

基金项目:国家自然科学基金项目（41271267，41671232）

作者	单位	E-mail
王梅	西南大学资源环境学院, 重庆 400716
蒋先军	西南大学资源环境学院, 重庆 400716	jiangxj@swu.edu.cn

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中文摘要:

土壤酸化是粘土矿物缓慢风化的自然过程，但近年来随着人类高强度的农业利用，土壤酸化现象逐渐加剧，而铵态氮肥的硝化作用是土壤酸化的主要贡献者之一。传统的施用石灰改良酸性土壤，常常会有反酸现象，并可能导致土壤板结。蒙脱石是碱性或中性土壤的主要粘土矿物组分，而在土壤酸化的过程中，蒙脱石被进一步风化掉。本文通过室内模拟实验，采用硝化动力学拟合及对净硝化速率的计算，分别研究了蒙脱石（Ca-M）和石灰（Ca-OH）对酸性黄壤硝化作用的影响。结果表明：酸性黄壤添加石灰或蒙脱石后，土壤均发生了显著的硝化作用，且硝化过程符合一级动力学模型N_NO₃=N₀+N_p（1-exp（-k₁t））（P<0.001）。Ca-OH 处理土壤样品的净硝化速率（3.429 mg·kg^-1·d^-1）显著大于Ca-M处理（2.381 mg·kg^-1·d^-1）；Ca-OH 处理土壤样品的潜在硝化速率（V_p）和平均硝化速率（V_a）在pH 值5.7 和6.2 时分别为6.42、8.58 mg N·kg^-1·d^-1和2.71、3.87 mg N·kg^-1·d^-1，均显著大于钙基蒙脱石处理（pH 值5.7 和6.2 时分别为3.40、4.56 mg N·kg^-1·d^-1和2.36、3.04 mg N·kg^-1·day^-1）。结果表明采用石灰改良酸性土壤发生复酸化现象的可能性及程度大于钙基蒙脱石，本研究为酸性土壤改良提供了新的参考。

英文摘要:

Soil acidification is known as a natural and slow process along with clay mineral weathering. In recent years however, with inten sive soil utilization in agriculture, soil acidification has increased dramatically and nitrification of ammonium nitrogen fertilizer is one of the main contributors to soil acidification. Lime application is the traditional practice to improve acidic soils but it often makes the soil acidic a gain leading to soil compaction in most cases. Montmorillonite is the main clay mineral component of alkaline or neutral soils, more so it is known to undergo further weathering processes during soil acidification. The laboratory-based incubations were used in this study, and nitri fication was measured while kinetic curves were fitted to check the effects of decreasing soil acidity by lime(Ca-OH)and montmorillonite (Ca-M)on nitrification of the acidic soil. The results showed that significant nitrification was observed both in Ca-OH and Ca-M treatments, and the nitrification process was fitted in the first-order kinetic model, N_NO₃=N₀+N_p(1-exp(-k₁t))(P<0.001). The net nitrification rate of Ca-OH treatment(3.429 mg·kg^-1·d^-1)was significantly higher than that of Ca-M treatment(2.381 mg·kg^-1·d^-1). The potential nitrifi cation rate(V_p)were 6.42, 8.58 mg N·kg^-1·d^-1 at pH 5.7 and 6.2 respectively, and the average nitrification rate(V_a)of Ca-OH treatment were 2.71, 3.88 mg N·kg^-1·d^-1 respectively, which were significantly greater than those of Ca-M treatment(V_p were 3.40, 4.56 mg N·kg^-1·d^-1 and V_a were 2.36, 3.04 mg N·kg^-1·d^-1 at pH 5.7 and 6.2 respectively). Therefore the net nitrification rate, potential nitrification rate(V_p) and average nitrification rate(V_a)of Ca-OH treatment were significantly higher than that of Ca-M treatment, suggesting that the possibili ty and degree of soil reacidification by using lime to improve acidic soil is greater than using calcium montmorillonite. This study will provide a new reference for the improvement of acid soils.

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