不同有机酸对石灰性土壤磷的活化效应及机理  

Low molecular weight organic acids activate insoluble soil P through competition adsorption sites and chelating reaction in calcareous soils

作　　者：章浩 王雪薇 褚贵新 ZHANG Hao;WANG Xue-wei;CHU Gui-xin(School of Life Science,Shaoxing University,Shaoxing,Zhejiang 312000,China)

机构地区：[1]绍兴文理学院生命与环境科学学院,浙江绍兴312000

出　　处：《植物营养与肥料学报》2024年第1期99-113,共15页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然科学基金项目(41161047)。

摘　　要：【目的】添加低分子量有机酸是活化土壤难溶性磷有效途径。比较研究几种低分子量有机酸及其组合对土壤磷的活化性能,为土壤磷的高效利用提供依据。【方法】低磷和高磷石灰性土壤选自新疆石河子,设置5个低分子有机酸添加处理:草酸、柠檬酸、黄腐酸、柠檬酸+草酸、草酸+柠檬酸+黄腐酸处理,和一个0.01mmol/L KCl对照。采用吸附平衡实验法测定土壤磷的吸附量;采用土壤吸附动力学实验法测定土壤磷的解吸动力学。采用常规和灭菌土壤培养方法,通过连续浸提法研究低分子有机酸及其组合对磷组分动态转化的影响和pH对磷的活化效应。【结果】Langmuir与Elovich模型均可较好地拟合土壤对磷的吸附热力学(R^(2)=0.852~0.994)与吸附动力学过程(R^(2)=0.882~0.975)。低磷土壤的最大吸附量(Q_(max))、最大缓冲容量(MBC)、吸附力常数(K_L)和吸附速率(b)均高于高磷土壤,表明低磷土壤对磷的吸附更强。低分子量有机酸添加均降低了Q_(max)、MBC和b。草酸对Q_(max)和MBC的降幅最大,低磷土壤降幅分别为28.5%和74.9%,高磷土壤分别为14.7%和73.3%。柠檬酸对低磷土壤的b值降幅最大(80.9%),草酸对高磷土壤的b值降幅最大(22.0%)。与CK相比,草酸添加显著提高了Olsen-P含量,草酸+柠檬酸效果次之,黄腐酸对磷的活化效果最差。不灭菌培养条件下,草酸和草酸+柠檬酸处理低磷土壤的Olsen-P含量分别增加了42.6%和18.5%,高磷土壤分别增加了27.3%和1.01%;草酸和草酸+柠檬酸处理的活性磷组分Resin-P在低磷土壤中分别增加了80.9%和77.4%,在高磷土壤中分别增加了79.5%和72.8%;非活性磷组分Di HCl-P在低磷土壤中分别降低了8.87%和5.89%,在高磷土壤中分别降低了8.83%和5.54%;Con HCl-P在低磷土壤中分别降低了25.1%和12.9%,在高磷土壤中分别降低了16.9%和5.30%。柠檬酸处理的Resin-P在低磷和高磷土壤中分别增加了70.2%和79.5%,而NaOH-P【Objectives】Low molecular weight organic acids(LMWOAs)have been noticed effective in mobilizing soil insoluble phosphorus(P).We compared the activating effects of LMWOAs,the possible mechanisms and the proper way of application.【Methods】The LMWOAs used in the research included oxalic acid(OA),citric acid(CA),fulvic acid(FA),oxalic acid plus citric acid(OA+CA),and the three acids together(OA+CA+FA),and KCl was used as control.The low-and high-P soils were collected from Shihezi City,Xinjiang.The P adsorption amount of soils was tested by adsorption balance experiment.The adsorption dynamics of P was tested by isotherm adsorption experiment.The P was fractioned by continuous extraction method and the pH was measured after the unsterilized and sterilized soils were incubated for 30 days.【Results】Langmuir and Elovich equation well fitted soil P adsorptive thermodynamics(R^(2)=0.852-0.994)and adsorptive dynamics processes(R^(2)=0.882-0.975)either in low-or high-P soil.The maximum P adsorption(Qmax),maximum buffer capacity(MBC),Langmuir coefficient(KL)and Elovich constant(b)in low-P soil were significantly higher than those in high-P soil,indicating the stronger P adsorption capacity of low-P soil.All the OA,CA,and FA addition notably decreased Qmax,MBC and b values.OA resulted in the largest decrease in Qmax and MBC values,with decrease by 28.5%and 74.9%in low-P soil,and by 14.7%and 73.3%in high-P soil.CA resulted in significant decrease of b value in low-P soil(80.9%),while OA did that by 22.0%in the high-P soil.Compared to CK,the highest Olsen-P content was exhibited in OA treated soil,followed in OA+CA soil,the least effect was in FA treated soil.Under unsterilized condition,OA and OA+CA significantly increased soil Olsen-P by 42.6%and 18.5%in low-P soil,and by 27.3%and 1.01%in high-P soil;increased Resin-P by 80.9%and 77.4%in low-P soil,and 79.5%and 72.8%in high-P soil;decreased Di HCl-P by 8.87%and 5.89%in low-P soil,and 8.83%and 5.54%in high-P soil;decreased Con HCl-P by 25.1%and 12.9%in low-P soil a

关 键 词：低分子量有机酸 吸附等温线 吸附动力学 磷有效性 磷组分转化 石灰性土壤 

分 类 号：S153.6[农业科学—土壤学]