Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1983 Hydrolysis of formamide and volatilization of ammonia from nitrogen fertilizers added to soils Heitor Cantarella Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agricultural Science Commons, Agriculture Commons, and the Agronomy and Crop Sciences Commons Recommended Citation Cantarella, Heitor, "Hydrolysis of formamide and volatilization of ammonia from nitrogen fertilizers added to soils " (1983). Retrospective Theses and Dissertations. 7700. https://lib.dr.iastate.edu/rtd/7700 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. 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These prints are available upon request from the Dissertations Customer Services Department. 5. Some pages in any document may have indistinct print. In all cases the best available copy has been filmed. Universi^ Micionlms International 300 N. Zeeb Road Ann Arbor, Ml 48106 8323269 Canta relia, Heitor HYDROLYSIS OF FORMAMIDE AND VOLATILIZATION OF AMMONIA FROM NITROGEN FERTILIZERS ADDED TO SOILS Iowa State University PH.D. 1983 University Microfilms IntsrnEltio nâl SOO N. Zeeb Road, Ann Arbor, Ml 48106 PLEASE NOTE: In all cases this material has been filmed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark V . 1. Glossy photographs or pages 2. Colored illustrations, paper or print 3. Photographs with darl^ background 4. Illustrations are poor copy 5. Pages witii black marks, not origin^ copy 6. Print shows through as there is text on both sides of page 7. 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For the Gradate College Iowa State University Ames, Iowa 1983 ii TABLE OF CONTENTS Page INTRODUCTION 1 LITERATURE REVIEW 5 Transformations of Amides in Soils 5 Methods of Analysis of Formamide 8 Formamide and Other Amides as Fertilizers 10 Volatilization of NH3 from N Fertilizers Applied to Soils 16 PART I. COLORIMETRIC DETERMINATION OF FORMAMIDE 42 INTRODUCTION 43 DESCRIPTION OF METHODS 46 Reagents 46 Procedure 47 RESULTS AND DISCUSSION 49 PART II. DETERMINATION OF FORMAMIDE ADDED TO SOILS 79 INTRODUCTION 80 MATERIALS AND METHODS 82 Materials 82 Reagents 82 Procedure 85 RESULTS AND DISCUSSION 87 iii Page PART III. HYDROLYSIS OF FORMAMU® ADDED TO SOILS 97 INTRODUCTION 98 MATERIALS AND METHODS 101 RESULTS AND DISCUSSION 103 PART IV. VOLATILIZATION OF AMMONIA FROM NITROGEN FERTILIZERS ADIBD TO SOILS 116 INTRODUCTION 117 MATERIALS AND METHODS 121 Materials 121 Ammonia Volatilization Chamber 121 Experimental Set-up 124 Description of Experiments 127 Chemical Analysis 132 RESULTS AND DISCUSSION 135 Ammonia Volatilization from Surface-Applied Fertilizers 135 Effect of Crop Residues and Placement of N Fertilizers on NHg Volatilization 159 Formamide Volatilization Following Its Application to Soils 186 SUMMARY AND CONCLUSIONS 192 LITERATURE CITED 198 ACKNOWLEDOIENTS 209 1 INTRODUCTION Aliphatic amides undergo enzymatic hydrolysis in soils, yielding NH^ and the corresponding carboxylic acids. Urea, which is also an amide, is one of the most commonly used N fertilizers. Several other compounds of the class of amides, including oxamide and formamide, have been shown to supply N to plants. Dry-matter yield and yield of N ob­ tained with amides as sources of N are usually similar to those obtained with conventional N fertilizers, such as urea and ammonium nitrate. Oxamide has low solubility in water. In soil, large granules of oxamide exhibit slow-release characteris­ tics, but the release of N from powdered oxamide is similar to that from soluble N sources such as ammonium nitrate, Formamide is liquid at room temperatures and is a good solvent for urea and many cimmonium salts, Formamide lowers the salting-out temperature of liquid mixtures and can be used to produce nonpressure liquid fertilizers of high N content. The fertilizer value of formamide was first recog­ nized in 1937. Since then, encouraging results with this compound have been obtained in both greenhouse and field experiments, Formamide is hydrolyzed in soils and the inorganic N produced accumulates as NO^ under aerobic conditions. How­ ever, studies on the course and rate of formamide hydrolysis 2 are hindered by the lack of a method of determination of formamide in soils. A method of analysis of formamide that seems suitable to be adapted to soil extracts involves the determination of traces of formamide colorimetrically by the hydroxamic acid-ferric complex formed from the reaction of Fe , in an acidic medium, vith the formohydroxamic acid produced from the reaction of formamide with hydroxy lamine under alkaline conditions. This method is relatively simple and rapid, and has the advantage that it is not subject to interference by the products of formamide hydrolysis in soils. Liquid fertilizers are most commonly employed for sur­ face application to soils. Fertilizers containing or produc­ ing NH^ are subject to NHg volatilization losses, especially if they are surface applied to calcareous soils". Surface application of these fertilizers is desirable if the com­ pounds produce an acid reaction upon dissolution and are applied on neutral or acid soils; however, fertilizers such as urea, which, upon hydrolysis, can cause substantial in­ creases in the soil pH around the fertilizer particle, are susceptible to NHg losses if surface applied even to acid soils. Ammonia volatilization losses from N fertilizers are enhanced by high soil pH, high soil temperature, high rates of fertilizer application, and by conditions that favor the drying process in the soil. Higher NH^ volatilization losses are observed from fertilizers applied to sandy than to heavy- 3 textured, high-CEC soils. Ammonia losses are reduced by- rainfall, irrigation, or mechanical incorporation of the surface-applied N fertilizers. Information available in the literature indicates that crop recovery of N is lower from surface-applied than from soil-incorporated oxamide and formamide, suggesting that volatilization losses, presumably as NH^, may occur. However, no direct measurements of NH^ volatilized from oxamide applied to soils have been made. The little information available on NH^ volatilization from formamide indicates that NHg does evolve from soils treated with surface-applied formamide and that the amount of NH^ lost increases with the increase in the rate of application and decreases with the increase in the CEC of the soil. If the potential of oxamide and formamide