HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lindsay, W. L. Articles by Norvell, W. A. Search for Related Content PubMed Articles by Lindsay, W. L. Articles by Norvell, W. A. Agricola Articles by Lindsay, W. L. Articles by Norvell, W. A.

Development of a DTPA Soil Test for Zinc, Iron, Manganese, and Copper¹

ABSTRACT

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 0.005M DTPA (diethylenetriaminepentaacetic acid), 0.1M triethanolamine, and 0.01M 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 hours. 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 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 four 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.

¹ Contribution from the Department of Agronomy, Colorado State Univ., Fort Collins, and the Connecticut Agric. Exp. Stn., New Haven. Published with the approval of the Director of the Colorado State Univ. Agric. Exp. Stn. as Scientific Series Paper no. 2327. Supported in part by Farmland Industries, Inc., Kansas City, Mo.

² Professor of Agronomy, Colorado State Univ., Fort Collins, CO 80523, and Associate Scientist, Connecticut Agric. Exp. Stn., New Haven, Conn., respectively.

Received for publication October 24, 1977. Accepted for publication February 1, 1978.

This article has been cited by other articles:

				M. O. Mendez, J. W. Neilson, and R. M. Maier Characterization of a Bacterial Community in an Abandoned Semiarid Lead-Zinc Mine Tailing Site Appl. Envir. Microbiol., June 15, 2008; 74(12): 3899 - 3907. [Abstract] [Full Text] [PDF]

				D. Gonzalez, A. Obrador, L. M. Lopez-Valdivia, and J. M. Alvarez Effect of Zinc Source Applied to Soils on its Availability to Navy Bean Soil Sci. Soc. Am. J., May 1, 2008; 72(3): 641 - 649. [Abstract] [Full Text] [PDF]

				M.T. Baca, E. Benitez, and R. Nogales Effect the Addition of Sugarcane Bagasse Composts On Micronutrient Assimilability in Ryegrass Waste Management Research, January 1, 1992; 10(1): 13 - 19. [Abstract] [PDF]