DEVELOPMENT OF A DTPA SOIL TEST FOR ZINC, IRON, MANGANESE, AND COPPER
DEVELOPMENT OF A DTPA SOIL TEST FOR ZINC, IRON, MANGANESE, AND COPPER
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DOI：
10.2136/sssaj1978.03615995004200030009x
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发表时间：
1978-01-01
影响因子：
2.9
通讯作者：
NORVELL, WA
中科院分区：
文献类型：
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作者：
LINDSAY, WL;NORVELL, WA
DTPA土壤测试，以确定近中性和石灰性土壤有效锌，铁，锰，铜不足的最大产量的作物。萃取剂由0.005 M DTPA（二亚乙基三胺五乙酸）、0.1 M三乙醇胺和0.01 M CaCl 2组成，pH值为7.3。土壤试验包括用20 ml提取剂摇动10 g风干土壤2 h。将浸出液过滤，用原子吸收分光光度法测定滤液中的Zn、Fe、Mn和Cu。土壤试验成功地分离了77个科罗拉多[美国]土壤的基础上，作物对锌，铁和锰肥料的反应。必须使用标准化的土壤准备、研磨和提取程序分别确定每种作物的关键营养水平。使用本文报告的程序，玉米的临界水平为：Zn为0.8 ppm，Fe为4.5 ppm，Mn暂定为1.0 ppm，Cu为0.2 ppm。土壤测试的开发部分基于理论考虑。萃取剂在pH 7.30下缓冲，并且含有CaCl 2，使得在约10倍于大气的CO2水平下建立与CaCO 3的平衡。因此，提取剂排除了CaCO3的溶解和通常植物不能利用的被吸留的营养物的释放。选择DTPA作为螯合剂，因为它可以有效地提取所有4种微量营养素金属。pH值、螯合剂浓度、振荡时间和提取温度等因素会影响微量营养素的提取量，并进行调整以获得最大的总体效果。
A DTPA soil test was developed to identify near-neutral and calcareous soils with insufficient available Zn, Fe, Mn, or Cu for maximum yields of crops. The extractant consists of 0.005 M DTPA (diethylenetriaminepentaacetic acid), 0.1 M triethanolamine and 0.01 M CaCl2, with a pH of 7.3. The soil test consists of shaking 10 g of air-dry soil with 20 ml of extractant for 2 h. The leachate is filtered, and Zn, Fe, Mn and Cu are measured in the filtrate by atomic absorption spectrophotometry. The soil test successfully separated 77 Colorado [USA] soils on the basis of crop response to Zn, Fe and Mn fertilizers. Critical nutrient levels must be determined separately for each crop using standardized procedures for soil preparation, grinding and extraction. The critical levels for corn using the procedures reported herein were: 0.8 ppm for Zn, 4.5 ppm for Fe and tentatively 1.0 ppm for Mn, and 0.2 ppm for Cu. Development of the soil test was based, in part, on theoretical considerations. The extractant is buffered at pH 7.30 and contains CaCl2 so that equilibrium with CaCO3 is established at a CO2 level about 10 times that of the atmosphere. Thus, the extractant precludes dissolution of CaCO3 and the release of occluded nutrients which are normally not available to plants. DTPA was selected as the chelating agent because it can effectively extract all 4 micronutrient metals. Factors such as pH, concentration of chelating agent, time of shaking and temperature of extraction affect the amount of micronutrients extracted and were adjusted for maximum overall effectiveness.