引用本文:李忠意, 白颖艳, 刘莉, 程永毅, 文绍明, 谢德体.土壤有机质对交换性酸测定结果的影响[J].西南大学学报(自然科学版),2018,40(11):119~126
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土壤有机质对交换性酸测定结果的影响
李忠意, 白颖艳, 刘莉, 程永毅, 文绍明, 谢德体1,2
1. 西南大学 资源环境学院, 重庆 400715;2. 重庆市丰都县农业生态环保检验检测站, 重庆 丰都 408200
摘要:
为探讨土壤有机质对两种常用的土壤交换性酸测定方法(BaCl2-TEA提取法和KCl淋溶法)结果的影响,选取了85个不同有机质质量分数的酸性土壤并采用BaCl2-TEA提取法和KCl淋溶法测定其交换性酸含量.结果表明,BaCl2-TEA提取法测得的土壤交换性酸含量远大于KCl淋溶法的测定结果.KCl淋溶法测得的土壤交换性酸含量与土壤pH值间的负相关性极有统计学意义(r=-0.79**),而BaCl2-TEA提取法测得的土壤交换性酸含量与土壤pH值间的相关性统计学意义(r=-0.08).但BaCl2-TEA提取法测得的土壤交换性酸含量却与土壤有机质质量分数间的正相关性极有统计学意义(r=0.94**).此外,由KCl淋溶法测得的土壤交换性酸进一步计算得到的盐基饱和度与土壤pH值间的相关性(r=0.69**)也大于BaCl2-TEA提取法(r=0.25*).通常土壤酸化越严重,土壤pH值越低,交换性酸含量越高,盐基饱和度越低.可以得出,土壤有机质会使BaCl2-TEA提取法的测定结果产生较大的正误差,而对KCl淋溶法的影响较小.由于土壤有机质中的腐殖酸会与BaCl2-TEA提取法中的有机弱碱TEA发生反应,增加TEA用量,从而使计算得到的土壤交换性酸的结果偏高.因此,对于高有机质质量分数的酸性土壤,不宜采用BaCl2-TEA提取法测定其交换性酸含量.但在KCl淋溶法中,由于K+对Al3+的交换能力较弱,使得该方法测得的土壤交换性酸含量偏低.因此,可乘以1.5左右的校正系数,以便能真实地反映出土壤交换性酸含量.
关键词:  交换性酸测定  BaCl2-TEA提取法  KCl淋溶法  土壤有机质
DOI:10.13718/j.cnki.xdzk.2018.11.017
分类号:P594;S153.4
基金项目:国家自然科学基金项目(41701256);重庆市博士后科研项目(Xm2016076);西南大学本科生创新基金项目(20162402007).
Influence of Soil Organic Matter on the Measurement of Soil Exchangeable Acidity
LI Zhong-yi, BAI Ying-yan, LIU Li, CHENG Yong-yi, WEN Shao-ming, XIE De-ti1,2
1. School of Resources and Environment, Southwest University, Chongqing 400715, China;2. Agroecological and Environmental Testing and Monitoring Station, Fengdu County, Fengdu Chongqing 408200, China
Abstract:
In order to investigate the effects of soil organic matter on the measurements of soil exchangeable acidities with different extraction methods, the exchangeable acidities of 85 acidic soils with different contents of organic matter were measured by the BaCl2-TEA (Triethanolamine) extraction method and the KCl leaching method. The results showed that the contents of soil exchangeable acidity measured by BaCl2-TEA extraction were much higher than those measured by the KCl leaching method. The correlation between soil pH and soil exchangeable acidities measured by the KCl leaching method (r=0.79**, p<0.01) was better than that measured by the BaCl2-TEA extraction method (r=0.08). However, there was a highly significant positive correlation between soil organic matter and soil exchangeable acidities obtained by the BaCl2-TEA extraction method (r=0.94**, p<0.01). In addition, the correlation between soil pH and base saturation calculated with the KCl leaching method (r=0.69**) was higher than that calculated with the BaCl2-TEA extraction method (r=0.25*). Generally, when the soil is acidified, the content of soil exchangeable acidity will increase and the base saturation will decrease. The humic acids in soil organic matter can react with TEA and increase the usage of TEA, thus inducing higher content of soil exchangeable acidities. Therefore, the BaCl2-TEA extraction method is not suitable for the measurement of exchangeable acidity in acidic soil with high content of organic matter. In addition, the soil exchangeable acidity measured by the KCl leaching method was low because of the weakly exchangeable ability of K+. Therefore, it is advisable to adjust the content of soil exchangeable acidity measured by the KCl leaching method with a coefficient of 1.5.
Key words:  measurement of soil exchangeable acidity  BaCl2-TEA extraction  KCl leaching  soil organic matter
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