不同添加量生物炭对酸性土壤镁吸附解吸特性的影响  

Effect of biochar on magnesium adsorption and desorption characteristics of acidic soil

作　　者：姜亚男 李梦婷 吴良泉 杨文浩 邢世和 JIANG Yanan;LI Mengting;WU Liangquan;YANG Wenhao;XING Shihe(College of Resources and Environment,International Magnesium Institute,Fujian Agriculture and Forestry University,Fuzhou 350002;University Key Laboratory of Soil Ecosystem Health and Regulation in Fujian Province,Fuzhou 350002)

机构地区：[1]福建农林大学资源与环境学院国际镁营养研究所,福州350002 [2]土壤生态系统健康与调控福建省高校重点实验室,福州350002

出　　处：《安徽农业大学学报》2021年第1期128-134,共7页Journal of Anhui Agricultural University

基　　金：国际镁营养研究所开放基金IMI2018-10资助。

摘　　要：为研究不同生物炭对酸性土壤镁吸附-解吸特性的影响,采集南方典型酸性缺镁土壤,开展等温吸附、动力吸附、解吸等试验进行探究。结果表明:随着平衡液浓度的增加,土壤镁的吸附量与解吸量增加。施用生物炭后,随生物炭添加量的增加,土壤镁吸附量降低;外源镁浓度不同时,生物炭对土壤镁吸附的影响不同,当外源镁浓度在60~200 mg·L^(-1)时,少量生物炭添加促进土壤镁的吸附;施用生物炭后吸附分配系数Kd降低,与CK对照处理相比,添加生物炭的T1-0.5%、T2-1%、T3-2%、T4-4%处理土壤对镁的吸附分配系数Kd平均值分别降低0.08、0.98、2.98、6.08kg·L^(-1);对试验结果进行拟合,发现Langmuir和Freundlich方程均能较好的拟合不同生物炭添加量后土壤镁吸附热力过程,且各处理拟合方程回归系数R2均为0.99。采用的土壤对镁吸附速率较快,在10min左右便基本达到平衡;对试验结果进行准一级动力方程、准二级动力方程以及颗粒内扩散方程拟合,发现3种动力方程的拟合效果均不理想。当平衡液浓度大于20mg·L^(-1)后,相较于对照处理,添加生物炭促进了土壤镁的解吸;随着生物炭施用量的增加,土壤镁解吸量减少,一定量的生物炭添加能够提高镁的解吸率,解吸率大小总体表现为:T4>T1>T2>T3>CK;T4处理镁的平均解吸率最高为14.70%,其次为T1处理11.02%,CK对照处理的平均解吸率最低为10.52%。施用生物炭后,土壤镁的吸附能力受到一定的抑制,解吸能力提高,镁释放量增加,镁的吸附能力与释放能力都随生物炭添加量的增加而下降。To explore the effects of different biochar on the adsorption and desorption of magnesium by acid soil,typical acid magnesium-deficient soils in south China were collected,test in isothermal adsorption,dynamic adsorption,and desorption were conducted.The results showed that the adsorption and desorption of soil magnesium increased with the increasing equilibrium solution concentration.After the application of biochar,the adsorption amounts of soil magnesium decreased with the increase of biochar.With different concentrations of exogenous magnesium,biochar had different effects on soil magnesium adsorption.When the concentration of exogenous magnesium was in the range of 60-200 mg·L^(-1),the small amount of biochar added could promote the magnesium adsorption by soil.After biochar application,the adsorption and distribution coefficient Kd was reduced.Compared with CK control treatment,the average value of the adsorption and distribution coefficient Kd of magnesium in the soil treated with biochar at T1-0.5%,T2-1%,T3-2%and T4-4%was reduced by 0.08,0.98,2.98,and 6.08 kg·L^(-1),respectively.By fitting the experimental results,it was found that both Langmuir and Freundlich equations could well fit the thermodynamic process of soil magnesium adsorption after addition of different amounts of biochar,and the regression coefficient R2 of each fitting equation was 0.99.The adsorption rate of magnesium by the soil adopted in this paper was fast,and the equilibrium basically reached in about 10 min.The quasi-first-order dynamic equation,quasi-second-order dynamic equation and intra-particle diffusion equation were not well fitted to the test results.When the equilibrium solution concentration was greater than 20 mg·L^(-1),the addition of biochar promoted the desorption of soil magnesium compared with the control treatment.With the increase of biochar application amount,the soil magnesium desorption amount decreased.A certain amount of biochar addition could improve the desorption rates of magnesium.The total desorption ra

关 键 词：酸性土壤 镁 吸附解吸 生物炭 

分 类 号：S153[农业科学—土壤学]