By-Product Usage in Fertilizer Micronutrients - ACS Symposium Series

Chapter 16

By-Product Usage in Fertilizer Micronutrients

Downloaded by PENNSYLVANIA STATE UNIV on September 6, 2012 | http://pubs.acs.org Publication Date: July 1, 1997 | doi: 10.1021/bk-1997-0668.ch016

James M . Wyatt Frit Industries, Inc., P.O. Box 1589, Ozark, A L 36361-1589

Nutrients supplied by f e r t i l i z e r s are divided into three categories: primary, secondary, and micronutrients. Neither the primary nutrients (nitrogen, phosphate, and potassium) nor the secondary nutrients (calcium, magnesium and sulfur) are the subject of this paper, but many by -products are u t i l i z e d beneficially i n the f e r t i l i z e r industry to provide these nutrients. Micronutrients refer to the remaining essential plant nutrients that must be present for plant growth, but are required only in very small or micro quantities. Nutrients that are c l a s s i f i e d as micronutrients are boron (Β), cobalt (Co), chlorine (Cl), copper (Cu), iron (Fe), manganese (Μn), molybdenum (Mo), vanadium (V), and zinc (Zn). The metallic forms of most of these metals are not available to plants. Chemical forms that are used are f r i t s , oxides, sulfates, nitrates, carbonates, and chelates. The physical forms i n which micronutrients are applied are liquids, suspensions, powders, and granules. Analytical methods followed by f e r t i l i z e r control o f f i c i a l s are those specified i n the f e r t i l i z e r section of the O f f i c i a l Methods of Analysis of The Association of O f f i c i a l Analytical Chemists (AOAC). Micronutrients are typically applied i n accordance with recommendations received from agronomic consultants, who consider as s o i l test results, the crop and cultivar being grown, tissue analysis of the growing plant, y i e l d levels, and s o i l conditions in a given geographical area. Micronutrient deficiencies occur most frequently in sandy s o i l s , high pH s o i l s , and older, highly-weathered s o i l s from which the nutrients have been leached. © 1997 American Chemical Society

In Agricultural Uses of By-Products and Wastes; Rechcigl, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1997.

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S i n c e a p l a n t ' s r o o t s y s t e m must i n t e r c e p t s o i l n u t r i e n t s , i t i s i m p o r t a n t f o r s o i l n u t r i e n t s t o be maintained at a high l e v e l to prevent d e f i c i e n c i e s i n crops, e s p e c i a l l y when h i g h y i e l d s a r e b e i n g s o u g h t . The a g r o n o m i c i m p o r t a n c e o f t h e l e v e l o f w a t e r s o l u b i l i t y o f t h e m i c r o n u t r i e n t compound has l o n g b e e n i n d i s p u t e w i t h i n t h e f e r t i l i z e r i n d u s t r y as has t h e a s s e r t i o n that a lower a p p l i c a t i o n r a t e of c h e l a t e d m i c r o n u t r i e n t s w i l l g i v e t h e same c r o p r e s p o n s e as a much h i g h e r r a t e o f oxides or s u l f a t e s . Placement r a t h e r than the source can r e d u c e t h e amount o f p r o d u c t u s e d . Banding or f o l i a r a p p l i c a t i o n i s more e f f e c t i v e t h a n b r o a d c a s t i n g m i c r o n u t r i e n t s t h u s l o w e r r a t e s may be a p p l i e d , b u t b r o a d c a s t i n g u t i l i z e s l e s s e x p e n s i v e m a t e r i a l s and t a k e s f a r l e s s t i m e and e q u i p m e n t . With g r a n u l a r products, the s i z e of the i n d i v i d u a l p a r t i c l e i s important. The l a r g e r t h e p a r t i c l e , t h e f e w e r p a r t i c l e s t h e r e w i l l be p e r u n i t o f a r e a . Granular product (made up o f v e r y f i n e i n d i v i d u a l p a r t i c l e s ) w i t h a d i a m e t e r b e t w e e n two and f o u r m i l l i m e t e r s i s t h e most commonly u s e d due t o t h a t b e i n g t h e t y p i c a l s i z e o f t h e n i t r o g e n , p h o s p h a t e , and p o t a s s i u m s o u r c e s . Powdered m i c r o n u t r i e n t s may be i n c o r p o r a t e d i n t o t h e f e r t i l i z e r g r a n u l e d u r i n g t h e manufacturing process. T h i s method r e s u l t s i n b e t t e r d i s t r i b u t i o n i n t h e s o i l compared t o a p h y s i c a l b l e n d o f m i c r o n u t r i e n t s and o t h e r f e r t i l i z e r m a t e r i a l s , b u t a l l f i e l d s u p o n w h i c h t h e f e r t i l i z e r i s a p p l i e d r e c e i v e t h e same m i c r o n u t r i e n t a p p l i c a t i o n . P h y s i c a l b l e n d s c a n be p r o d u c e d i n s m a l l l o t s , t h u s o f f e r i n g a method t o i n c l u d e o n l y t h e m i c r o n u t r i e n t s n e e d e d by a p a r t i c u l a r f i e l d . Coating p o w d e r s o n t o g r a n u l e s i n a b l e n d e r i s a n o t h e r method o f manufacturing. However, t h e h a n d l i n g o f d r y , d u s t y p o w d e r s i s n o t a c c e p t a b l e t o most b l e n d e r s , so t h i s i s n o t a v e r y widespread p r a c t i c e . L i q u i d f e r t i l i z e r s may be t r u e s o l u t i o n s o r suspensions. L i q u i d f e r t i l i z e r c a n be a p p l i e d u n i f o r m l y and a l l o w t h e amount o f m i c r o n u t r i e n t s a p p l i e d t o a f i e l d t o vary. R e a c t i o n s b e t w e e n m i c r o n u t r i e n t s and o t h e r f e r t i l i z e r components c a n o c c u r and p r e s e n t p r o b l e m s . I n some i n s t a n c e s m i c r o n u t r i e n t s a r e a p p l i e d a l o n e , a s i n a f o l i a r a p p l i c a t i o n of a l i q u i d m i c r o n u t r i e n t . T h i s a p p l i c a t i o n may be t o c o r r e c t a d e f i c i e n c y w h i c h becomes a p p a r e n t d u r i n g t h e g r o w i n g s e a s o n o r may be due t o a h i g h pH o r some o t h e r s o i l c o n d i t i o n w h i c h c o n v e r t s s o i l - a p p l i e d m i c r o n u t r i e n t s t o an u n a v a i l a b l e f o r m .



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D u r i n g t h e e a r l y p e r i o d s o f o u r country's development, i t was common f o r v e r y l i t t l e f e r t i l i z e r t o be u s e d a n d t h e l a n d t o be f a r m e d u n t i l t h e s o i l s were d e p l e t e d o f n u t r i e n t s and t h e n t h e f a r m e r move a n d l e a v e t h e l a n d f a l l o w . In the 1800s a n d e a r l y t w e n t i e t h c e n t u r y , f a r m e r s b e g a n t o u s e bone m e a l , t a n k a g e ( a n i m a l r e n d e r i n g w a s t e s ) , manure, f i s h m e a l , guano, c o t t o n h u l l a s h e s , a n d r o c k s u p e r p h o s p h a t e a s fertilizers. M i c r o n u t r i e n t s were i n c l u d e d i n f e r t i l i z e r s due t o t h e i r p r e s e n c e i n t h e s e m a t e r i a l s . A s a n example, one s t u d y f o u n d t h a t manure c o n t a i n e d a n a v e r a g e o f 20 ppm B, 201 ppm Mn, 1 ppm Co, 16 ppm Cu, 96 ppm Zn, a n d 2 ppm Mo (Russell). A c c o r d i n g t o The F e r t i l i z e r Handbook, bone m e a l c o n t a i n s 20,000 ppm Zn, n o r m a l s u p e r p h o s p h a t e c o n t a i n s 10,0000 ppm Zn, a n d c o t t o n h u l l a s h e s c o n t a i n 40,000 ppm Cu, 60,000 ppm Mn, a n d 70,000 ppm Zn. A l l o f t h e s e m a t e r i a l s were u s e d i n l a r g e v o l u m e s b u t c o n t a i n e d r e l a t i v e l y l o w l e v e l s o f n u t r i e n t s . T h e s e m a t e r i a l s were commonly u s e d a s l a t e a s t h e 1960s. P l a n t v a r i e t i e s commonly u s e d , row w i d t h , a n d p l a n t p o p u l a t i o n s were s u c h t h a t t h e n u t r i e n t demands p l a c e d o n t h e s o i l s a n d t h e d e p l e t i o n o f m i c r o n u t r i e n t l e v e l s i n t h e s o i l s were f a r l e s s t h a n t o d a y . U s i n g c o r n a s a n example, i n 1940 c o r n p l a n t p o p u l a t i o n s were 10-12,000 p e r a c r e . By t h e 1950s t h e p l a n t p o p u l a t i o n s h a d i n c r e a s e d t o 16,000 ( A l d r i c h ) , a n d t o d a y we s e e 24,000 p l a n t s p e r a c r e a s t h e norm (NASS). P r i o r t o 1935, t h e a v e r a g e c o r n y i e l d h a d n o t c h a n g e d s i n c e r e c o r d s were f i r s t k e p t i n 1880. However, f r o m 1935 t o 1960 a v e r a g e y i e l d s i n c r e a s e d b y 140% (25 B u / a c r e t o 60 B u / a c r e ) a n d f r o m 1960 u n t i l t h e p r e s e n t , a v e r a g e y i e l d s have i n c r e a s e d f r o m 60 B u / a c r e t o 110 B u / a c r e o r a n o t h e r 80% (NASS). S i n c e 1980 l i t t l e c h a n g e h a s o c c u r r e d i n a v e r a g e y i e l d s due t o t h e emphasis p l a c e d on m i n i m i z i n g i n p u t s and t h e e x c e s s g r a i n i n world s t o c k p i l e s . M i c r o n u t r i e n t d e f i c i e n c i e s have b e e n r e p o r t e d i n t h e U n i t e d S t a t e s s i n c e t h e 1920s (Cunningham) b u t were n o t addressed by the f e r t i l i z e r o r farming sectors u n t i l the 1960s. The f i r s t n a t i o n a l s u r v e y o n m i c r o n u t r i e n t d e f i c i e n c i e s was done i n 1960 b y t h e C o u n c i l o n F e r t i l i z e r A p p l i c a t i o n a n d was f o l l o w e d b y a s e r i e s o f s u r v e y s w h i c h c u l m i n a t e d i n a r e p o r t b y t h e S o i l T e s t i n g Committee o f t h e S o i l Science S o c i e t y o f America. T h e i r r e p o r t l i s t e d s p e c i f i c m i c r o n u t r i e n t n e e d s b y c r o p a n d gave r e c o m m e n d a t i o n s f o r c o r r e c t i v e m e a s u r e s (Cunningham). M i c r o n u t r i e n t usage has been growing s t e a d i l y s i n c e t h e 1960s. The b i g g e s t i n c r e a s e was i n t h e 1973-1980 p e r i o d when m a r g i n a l l a n d was b r o u g h t i n t o p r o d u c t i o n due t o h i g h


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g r a i n p r i c e s and easy farm c r e d i t . New c r o p p i n g p r a c t i c e s were a d o p t e d t h a t e m p h a s i z e d maximum y i e l d . As f e r t i l i z e r r a t e s i n c r e a s e d , o t h e r f a c t o r s l i m i t i n g maximum y i e l d were r e v e a l e d , such as i n s u f f i c i e n t m i c r o n u t r i e n t l e v e l s i n t h e soil. During t h i s p e r i o d , m i c r o n u t r i e n t use i n c r e a s e d and new m i c r o n u t r i e n t s o u r c e s f r o m b y - p r o d u c t s i n c r e a s e d dramatically. Today, most m i c r o n u t r i e n t s a r e p r o d u c e d f r o m by-product m a t e r i a l s . I n 1983, t h e g r o w t h i n f e r t i l i z e r u s a g e s t o p p e d when o n e - t h i r d o f U.S. c o r n a n d wheat a c r e a g e was removed f r o m p r o d u c t i o n when t h e g o v e r n m e n t ' s payment i n k i n d (PIK) p r o g r a m was i m p l e m e n t e d . T h i s program gave s u r p l u s g r a i n i n government s t o r a g e t o farmers i n exchange f o r t h e i r t a k i n g land out o f production. S i n c e then and u n t i l r e c e n t l y , g o v e r n m e n t p r o g r a m s have c o n t i n u e d t o e m p h a s i z e r e d u c t i o n i n b o t h p l a n t e d acreage and crop p r o d u c t i o n . The new c r e d o f o r t h e 80s was maximum e c o n o m i c y i e l d , w h i c h i n t h e 90s became maximum s u s t a i n a b l e y i e l d . With the d e p l e t i o n o f world g r a i n r e s e r v e s t h i s summer a n d i n c r e a s e s i n g r a i n p r i c e s , a new e m p h a s i s w i l l p r o b a b l y be p l a c e d o n i n c r e a s e d p r o d u c t i o n , b u t w i t h f a r m e r s a n d t h e government t a k i n g a more c a u t i o u s a p p r o a c h t h a n i n t h e 1970s. W h i l e t h e above m e n t i o n e d c h a n g e s i n c r o p p i n g p r a c t i c e s were o c c u r r i n g a n d g r e a t e r a t t e n t i o n was b e i n g p a i d t o s o i l d e f i c i e n c i e s , g o v e r n m e n t a l r e g u l a t i o n s were b e i n g p u t i n place to eliminate a i r pollution. P o l l u t i o n from automobile e x h a u s t a n d t h e s m o k e s t a c k s o f t h e n a t i o n ' s power p l a n t s , s t e e l m i l l s , copper, z i n c , b r a s s and bronze s m e l t e r s , and f o u n d r i e s h a d s e r v e d a s m a j o r s o u r c e s o f some s e c o n d a r y n u t r i e n t s and m i c r o n u t i e n t s . A s t h e a i r was c l e a n e d up, p a r t i c u l a t e f r o m p o l l u t i o n no l o n g e r p r o v i d e d n u t r i e n t s . Smokestacks c a n s t i l l p r o v i d e secondary n u t r i e n t s and m i c r o n u t r i e n t s , b u t i n a d i f f e r e n t form--baghouse d u s t , s c r u b b e r s l u d g e , o r o t h e r t y p e s o f m a t e r i a l from an a i r p o l l u t i o n c o n t r o l system. T h e r e a r e , however, many l i m i t s on b y - p r o d u c t u s e b e c a u s e o f t h e i r p h y s i c a l f o r m , h i g h f r e i g h t c o s t s f o r l o w a n a l y s i s p r o d u c t s , l a c k o f a way f o r an i n d i v i d u a l f a r m e r t o a p p l y t h e s e m a t e r i a l s , a n d f e d e r a l regulations. These f a c t o r s p r e s e n t insurmountable barriers to d i r e c t use o f these m a t e r i a l s . The f e d e r a l r e g u l a t i o n s h a v i n g t h e most i m p a c t o n r e c y c l i n g were i n t r o d u c e d a s p a r t o f t h e R e s o u r c e C o n s e r v a t i o n a n d R e c o v e r y A c t o f 1976 (RCRA). The s t a t e d p u r p o s e o f t h e a c t was t o e n c o u r a g e t h e r e c o v e r y a n d r e c y c l i n g o f w a s t e s a n d t o r e d u c e t h e volume o f m a t e r i a l s being l a n d f i l l e d o r improperly disposed. Regulations



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i m p l e m e n t i n g RCRA a r e f o u n d i n 40 CFR, P a r t s 260-272. H a z a r d o u s w a s t e c a t e g o r i e s were c r e a t e d f o r m a t e r i a l s p o s i n g s p e c i a l hazards. R e g u l a t i o n s were p r o m u l g a t e d c o n t r o l l i n g t h e u s e , t r a n s p o r t a t i o n , s t o r a g e , and d i s p o s a l o f c e r t a i n wastes. Some m a t e r i a l s were i n c l u d e d by name ( l i s t e d w a s t e ) , o t h e r s were i n c l u d e d b e c a u s e o f a c h a r a c t e r i s t i c ( c h a r a c t e r i s t i c waste) s u c h as c o r r o s i v i t y o r f l a m m a b i l i t y . A t r a c k i n g s y s t e m f o r h a z a r d o u s w a s t e s was created, r e q u i r i n g t h a t w a s t e s be m a n i f e s t e d when t r a n s p o r t e d and t h a t any f a c i l i t y g e n e r a t i n g o r a c c e p t i n g h a z a r d o u s w a s t e s had t o be p e r m i t t e d by EPA t o a s s u r e t h e s a f e s t o r a g e , h a n d l i n g , and d i s p o s a l o f t h e w a s t e . R e s t r i c t i o n s on how t h e s e m a t e r i a l s c o u l d be h a n d l e d were e s t a b l i s h e d . The g r e a t e s t i m p a c t on m i c r o n u t r i e n t raw m a t e r i a l s came f r o m r e g u l a t i o n s m a k i n g any m a t e r i a l c a p t u r e d i n a b a g h o u s e o r e l e c t r o s t a t i c p r e c i p i t a t o r a s l u d g e ( s i n c e t h i s equipment s e r v e s t h e same p u r p o s e as a s c r u b b e r and a s c r u b b e r s l u d g e i s by " d e f i n i t i o n " hazardous; t h e r e f o r e , baghouse o r p r e c i p i t a t o r d u s t must a l s o be a h a z a r d o u s w a s t e ) . Under RCRA t h e d i s p o s a l o f c e r t a i n h a z a r d o u s w a s t e s by p l a c i n g them on t h e l a n d o r b u r y i n g i n u n r e g u l a t e d l a n d f i l l s was prohibited. T h i s p r o h i b i t i o n i n c l u d e s any p r o d u c t " d e r i v e d f r o m " a l i s t e d h a z a r d o u s w a s t e , r e g a r d l e s s o f any b e n e f i t s t h a t may d e r i v e f r o m i t s u s e (40 CFR 2 6 1 . 3 ) . In the case o f f e r t i l i z e r s , a d e t e r m i n a t i o n was made t h a t a l i s t e d w a s t e , o r a m a t e r i a l " d e r i v e d f r o m " one o f t h e s e w a s t e s b y b e i n g u t i l i z e d i n a f e r t i l i z e r was b e i n g p l a c e d on t h e l a n d and t h i s u s e c o n s t i t u t e d d i s p o s a l and was p r o h i b i t e d u n d e r t h e l a n d ban. T h i s o b v i o u s l y has had a " c h i l l i n g " e f f e c t on t h e u s e o f many b a g h o u s e d u s t s and s c r u b b e r s l u d g e s i n f e r t i l i z e r s due t o r e c o r d k e e p i n g r e q u i r e m e n t s , t h e c o s t o f mandatory i n s u r a n c e coverage f o r hazardous waste a c t i v i t y , and a l l o t h e r c o s t s a s s o c i a t e d w i t h c o m p l i a n c e w i t h an e v e r g r o w i n g number o f burdensome r e g u l a t i o n s . Prior to 1980 when t h e r e g u l a t i o n s f i r s t were p u t i n t o p l a c e , l a r g e q u a n t i t i e s o f b a g h o u s e d u s t and s c r u b b e r s l u d g e were u t i l i z e d as m i c r o n u t r i e n t raw m a t e r i a l s . Some w a s t e s c o n t a i n i n g h i g h l e v e l s of z i n c are s t i l l u t i l i z e d today but i n d e c r e a s i n g amounts. Many o f t h e s e m a t e r i a l s c o n t a i n u n w a n t e d l e a d , cadmium, n i c k e l , chromium, and a r s e n i c as i m p u r i t i e s t h a t render the m a t e r i a l s c h a r a c t e r i s t i c a l l y hazardous. Whether any d a n g e r i s p o s e d by p r o c e s s i n g a n d / o r a p p l y i n g a m i c r o n u t r i e n t c o n t a i n i n g l e a d and cadmium i s o f some d e b a t e . A m a t e r i a l c a n be t e s t e d t o d e t e r m i n e i f i t s h o u l d be c o n s i d e r e d a h a z a r d o u s w a s t e by s u b j e c t i n g i t t o



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the T o x i c i t y C h a r a c t e r i s t i c L e a c h i n g Procedure (TCLP). I f the l e v e l o f c e r t a i n designated metals a r e i n excess o f s p e c i f i e d l i m i t s , t h e m a t e r i a l i s c o n s i d e r e d a hazardous waste. There i s an o n - g o i n g debate between r e g u l a t o r s and g e n e r a t o r s a s t o what i s a p r o d u c t , c o - p r o d u c t , b y - p r o d u c t , or waste. I f a m a t e r i a l i s n o t a w a s t e , i t c a n n o t be a hazardous waste r e g a r d l e s s o f i t s c h a r a c t e r i s t i c s . W h i l e some o f t h e l i s t e d a n d c h a r a c t e r i s t i c w a s t e s were b e i n g b u r i e d o r "dumped," o t h e r s were b e i n g b e n e f i c i a l l y r e c y c l e d , b r i n g i n g s i g n i f i c a n t economic v a l u e . A s w i t h most r e g u l a t o r y enforcement, every m a t e r i a l covered by t h e r e g u l a t i o n s was t r e a t e d t h e same w i t h few e x c e p t i o n s . I n the case o f e l e c t r i c a r c furnace dust(K061), a l i s t e d h a z a r d o u s w a s t e , a t e m p o r a r y e x e m p t i o n f r o m RCRA was g r a n t e d f o r i t s use i n f e r t i l i z e r as l o n g as i t undergoes a c h e m i c a l c h a n g e , c a n be u s e d w i t h o u t f u r t h e r p r o c e s s i n g , a n d i s r e g i s t e r e d f o r s a l e a s a f e r t i l i z e r (50 CFR 666) . T h i s e x e m p t i o n was g r a n t e d a s a r e s u l t o f e v i d e n c e s u b m i t t e d t o t h e EPA s h o w i n g t h a t w i t h o u t KO61 t h e r e w o u l d n o t be a n adequate s u p p l y o f z i n c f o r use as a m i c r o n u t r i e n t , a d d i t i o n a l l y t h e l e a d a n d cadmium p r e s e n t i n K 0 6 1 - d e r i v e d p r o d u c t s w o u l d c a u s e no s i g n i f i c a n t change i n s o i l c o n c e n t r a t i o n s when a p p l i e d a t n o r m a l r a t e s . It i s possible t o h a v e a m a t e r i a l removed f r o m RCRA a u t h o r i t y i f i t c a n b e p r o v e n t h a t i t p o s e s no r i s k o r e x h i b i t s none o f t h e h a z a r d o u s c h a r a c t e r i s t i c s f o r w h i c h i t was i n i t i a l l y l i s t e d . T h i s i s not a simple o r easy task. Many c o m p a n i e s who i n t h e p a s t s o l d t h e i r b a g h o u s e d u s t o r s c r u b b e r s l u d g e f o r u s e i n f e r t i l i z e r s a r e now p a y i n g huge amounts t o have t h e s e m a t e r i a l s r e c y c l e d o r d i s p o s e d o f i n a l i c e n s e d treatment f a c i l i t y , recovery f a c i l i t y , o r p e r m i t t e d l a n d f i l l s . Some t r e a t m e n t p r o c e s s e s t u r n m a t e r i a l s i n t o i n s o l u b l e b r i q u e t t e s , which a r e then b u r i e d , but i n most c a s e s t h e s e m a t e r i a l s a r e s t a b i l i z e d b y m i x i n g w i t h cement o r o t h e r b i n d e r s a n d s i m p l y b u r i e d i n a r e g u l a t e d landfill. I n c a s e s where t h e m e t a l s a r e b e i n g r e c o v e r e d i n a p r o c e s s d e c l a r e d t o be t h e b e s t d e m o n s t r a t e d available t e c h n o l o g y (BDAT), t h e y c a n be s o l d e v e n f o r u s e a s f e r t i l i z e r s . I n one BDAT p r o c e s s t h e r e c o v e r e d m a t e r i a l h a s t h e h a r m l e s s i m p u r i t y ( i r o n ) removed, b u t t h e h e a v y m e t a l s a r e s t i l l p r e s e n t ( a l b e i t i n a more c o n c e n t r a t e d f o r m ) . T h i s m a t e r i a l c a n t h e n be u t i l i z e d a s a f e r t i l i z e r w i t h no r e s t r i c t i o n s . Some p r o c e s s e s do remove t h e l e a d a n d cadmium a t a h i g h c o s t . The r e s u l t i n g p r o d u c t i s o f t e n t o o e x p e n s i v e f o r use as a f e r t i l i z e r m i c r o n u t r i e n t .


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A d i s c u s s i o n o f each o f t h e m i c r o n u t r i e n t s and t h e by p r o d u c t s f r o m w h i c h t h e y c a n be d e r i v e d f o l l o w s . An attempt w i l l be made t o e x p l a i n t h e a v a i l a b l e t y p e s o f m a t e r i a l s a n d what p h y s i c a l o r c h e m i c a l c h a r a c t e r i s t i c m i g h t l i m i t a product's use. Boron. Boron i s c r i t i c a l t o the germination o f p o l l e n g r a i n s and t o c e l l w a l l f o r m a t i o n . B o r o n d e f i c i e n c y may appear i n v e g e t a b l e , f r u i t , and g r a i n c r o p s . Typical symptoms o f b o r o n d e f i c i e n c y i n c o r n a r e e a r s t h a t a r e p o o r l y f i l l e d o r t w i s t e d i n appearance. In sugar beets, b r o c c o l i , a n d c a u l i f l o w e r t h e d e f i c i e n c y may a p p e a r a s a h o l l o w a r e a i n t h e stem, w h i l e i n p e a n u t s i t may a p p e a r a s a hollow heart, a void i n the center of the nut. D e f i c i e n c i e s o f b o r o n were r e p o r t e d i n 44 s t a t e s i n a 1966 s u r v e y b y B u r g e s s (Cunningham). A s o i l i s considered deficient i f i t c o n t a i n s l e s s t h a n .3 ppm a n d t h e t y p i c a l a p p l i c a t i o n i s 1-1.5 p o u n d s o f Β p e r a c r e . Boron usage has been f a i r l y c o n s t a n t f o r t h e p a s t t h i r t y y e a r s w i t h e s t i m a t e s o f about 5,000 t o n s o f e l e m e n t a l Β b e i n g u t i l i z e d a s f e r t i l i z e r borate. E s t i m a t e s o f b o r o n c o n s u m p t i o n have b e e n t h e most r e l i a b l e o f a l l o f t h e m i c r o n u t r i e n t s . T h e r e a r e two domestic producers o f borate products. A l l i m p o r t s c a n be t r a c e d b y e x a m i n i n g i m p o r t r e c o r d s m a i n t a i n e d b y t h e U.S. Customs S e r v i c e . I n t h e p a s t t w e n t y y e a r s , i m p o r t s o f b o r a t e p r o d u c t s from Turkey and South American c o u n t r i e s have i n c r e a s e d , b u t t h e i r p r i m a r y u s e has been f o r industrial applications. The c h e m i c a l f o r m s c a n v a r y , b u t s o d i u m b o r a t e i s t h e most commonly u s e d f o r m b o t h f o r i n d u s t r i a l and a g r i c u l t u r a l a p p l i c a t i o n s . There has been an i n c r e a s e i n the use o f sodium-calcium borate (ulexite) i n t h e p a s t few y e a r s due t o t h e a v a i l a b i l i t y o f l o w c o s t m a t e r i a l s from South America as w e l l as h i g h q u a l i t y u l e x i t e from Turkey. Calcium b o r a t e (colemanite) has a l s o been u t i l i z e d i n f e r t i l i z e r s f o r many y e a r s , b u t i t s u s e h a s b e e n l i m i t e d due t o s u p p l y p r o b l e m s a s w e l l a s i t s r e l a t i v e l y high cost. The w a t e r s o l u b i l i t y l e v e l s o f v a r i o u s b o r o n s o u r c e s a r e o f c o n c e r n due t o t h e p o t e n t i a l f o r w a t e r l e a c h i n g b o r o n o u t o f t h e p l a n t ' s r o o t zone i n c o a r s e t e x t u r e d o r s a n d y s o i l s , where most b o r o n d e f i c i e n c i e s a r e f o u n d . B o r o n t o x i c i t y p r o b l e m s c a n a r i s e when e x c e s s i v e l e v e l s o f b o r o n a r e a p p l i e d , a n d f o r t h i s r e a s o n , some u s e r s p r e f e r a boron source that i s not a l l immediately s o l u b l e , such as


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u l e x i t e o r colemanite. Boron s l a g s a r e not r e a d i l y s o l u b l e and a r e u s e d t o s u p p l y b o r o n t o c r o p s grown i n s o i l s t h a t are e a s i l y l e a c h e d . Few b y - p r o d u c t s a r e a v a i l a b l e f o r u s e a s b o r o n s o u r c e s . Some b a g h o u s e d u s t s f r o m g l a s s b e a d p r o d u c t i o n a n d s l a g s c r e a t e d by the f l u x i n g o f metal recovery smelters c o n t a i n boron, as w e l l as o t h e r metals, and a r e u t i l i z e d on a limited basis. Chlorine. C h l o r i n e i s r a r e l y d e f i c i e n t i n t h e s o i l due t o i t s presence i n muriate o f potash (potassium c h l o r i d e ) , w h i c h i s t h e most commonly u s e d p o t a s s i u m f e r t i l i z e r . There i s c u r r e n t l y no p r a c t i c a l r e a s o n f o r b y - p r o d u c t c h l o r i n e s o u r c e s t o be u s e d a s a f e r t i l i z e r . As w i t h s e v e r a l o t h e r m i c r o n u t r i e n t s , t h e r e i s c o n c e r n about c h l o r i n e t o x i c i t y o r l e a f b u r n from i t s a p p l i c a t i o n on c e r t a i n c r o p s . For this r e a s o n p o t a s s i u m s u l f a t e and potassium n i t r a t e a r e used i n greenhouses and on l e a f c r o p s . Cobalt. C o b a l t i s n e e d e d b y legume r o o t n o d u l e s t o f i x a t m o s p h e r i c n i t r o g e n . L i k e molybdenum, i t i s u s e d b y t h e p l a n t a n d i n f e r t i l i z e r s i n e x t r e m e l y s m a l l q u a n t i t i e s due t o c o s t a n d t h e f a c t t h a t i t c a n be c o a t e d o n t o s e e d o r be f o l i a r a p p l i e d i f i t i s needed. Due t o a n u n u s u a l s o i l c o n d i t i o n , r e l a t i v e l y l a r g e q u a n t i t i e s o f cobalt are used i n New Z e a l a n d a n d A u s t r a l i a . The u s a g e o f c o b a l t t h e r e f l u c t u a t e s w i t h t h e p r i c e o f c o b a l t and sheep. B y - p r o d u c t c o b a l t c a n be f o u n d i n s p e n t c a t a l y s t o r from o f f - g r a d e c o b a l t o x i d e and s u l f a t e p r o d u c t s . Copper. Copper i s needed f o r c h l o r o p h y l l f o r m a t i o n i n t h e p l a n t . Where c o p p e r i s u s e d a s a f u n g i c i d e , t h e n e e d f o r i t s use as a m i c r o n u t r i e n t f e r t i l i z e r i s reduced. Copper d e f i c i e n c i e s were r e p o r t e d i n 14 s t a t e s i n t h e 1966 s u r v e y by Burgess(Cunningham). I n a r r i v i n g a t t h e t o t a l amount o f c o p p e r u s e d a s a f e r t i l i z e r , one must be c a r e f u l t o t a k e t h i s dual use i n t o account. The 1984 USDA r e p o r t e s t i m a t e d f e r t i l i z e r u s e a t 1,100 m e t r i c t o n s o f e l e m e n t a l c o p p e r w h i l e t h e 1980 e s t i m a t e was 1,500 t o n s ( M o r t v e d t ) . Frit's e s t i m a t e f o r c o p p e r u s e i n 1995 i s 1,100 t o n s o n a n elemental basis. The m a j o r r e a s o n f o r t h e d e c l i n e i n t h e u s e o f c o p p e r i s i t s c o s t v e r s u s commodity p r i c e s , e s p e c i a l l y wheat.



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C o p p e r u s e d f o r f e r t i l i z e r s must be e x t r a c t a b l e byh y d r o c h l o r i c a c i d i f i t t o be g u a r a n t e e d a s a p l a n t nutrient. M e t a l l i c c o p p e r a n d some o f t h e c o p p e r c o n t a i n e d i n b r a s s s l a g s a n d skimmings i s n o t h y d r o c h l o r i c a c i d extractable. However, t h i s c o p p e r c a n be r e c o v e r e d b y n i t r i c a c i d e x t r a c t i o n t o produce copper n i t r a t e o r by h e a t i n g t o produce copper o x i d e s . Copper o x i d e and copper s u l f a t e are the primary sources of f e r t i l i z e r copper. A l l d o m e s t i c a l l y p r o d u c e d c o p p e r s u l f a t e i s now p r o d u c e d f r o m copper scrap. U s e a b l e b y - p r o d u c t c o p p e r c a n be f o u n d i n v a r i o u s petroleum r e f i n i n g c a t a l y s t s , copper r e c o v e r y o p e r a t i o n s , s m e l t e r e f f l u e n t streams, f u r n a c e s l a g s , s c a l e s from copper w i r e drawing, copper p l a t i n g wastes, and baghouse d u s t from copper tube manufacturing. Iron. The c o n s u m p t i o n o f i r o n h a s i n c r e a s e d s u b s t a n t i a l l y i n t h e l a s t decade w i t h t h e growth i n usage o f " s p e c i a l i z e d " t u r f f e r t i l i z e r s that contain iron. Burgess r e p o r t e d i n 1966 t h a t 25 s t a t e s h a d i r o n d e f i c i e n c i e s i n t h e i r soils(Cunningham). I r o n s e r v e s as an oxygen c a r r i e r i n t h e p l a n t and i s an i n t e g r a l p a r t o f t h e c h l o r o p h y l l m o l e c u l e . I r o n w i l l c a u s e t u r f g r a s s e s t o become d a r k e r g r e e n i n c o l o r , w h i c h i s a s s o c i a t e d w i t h a h e a l t h y lawn. I n 1984, i r o n u s e was e s t i m a t e d a t 5,900 m e t r i c t o n s o n a 100% i r o n b a s i s ( M o r t v e d t ) . F r i t ' s e s t i m a t e f o r 1995 i s 6,400 t o n s . I r o n d e f i c i e n c i e s c a n o c c u r due t o a n i m b a l a n c e o f i r o n w i t h molybdenum, c o p p e r , manganese, a n d p h o s p h a t e , o r f r o m a h i g h s o i l pH(Olsen). I r o n s u l f a t e from the n e u t r a l i z a t i o n o f wastes from t h e c l e a n i n g o f s t e e l c o i l s and s h e e t s p r i o r t o g a l v a n i z i n g and from t i t a n i u m o x i d e p r o d u c t i o n i s w i d e s p r e a d i n u s e . I r o n o x i d e and s l a g s from copper s m e l t i n g , i r o n baghouse d u s t s , and m i l l s c a l e from p r i m a r y s t e e l p r o d u c t i o n are a l s o u s e d i n l a r g e q u a n t i t i e s t o p r o v i d e an i n e x p e n s i v e source of i r o n f o r f e r t i l i z e r s . Manganese. Manganese f u n c t i o n s a s p a r t o f t h e enzyme s y s t e m of p l a n t s and a i d s i n c h l o r o p h y l l p r o d u c t i o n . D e f i c i e n c i e s a r e t y p i c a l l y f o u n d i n wet, c o l d s o i l s o r s o i l s c o n t a i n i n g high l e v e l s of organic matter. Thirty states reported manganese d e f i c i e n c i e s i n 1 9 6 6 ( C u n n i n g h a m ) . The u s e o f manganese i n f e r t i l i z e r s h a s r e m a i n e d f a i r l y c o n s t a n t f r o m 1984 t o 1995. The 1984 USDA e s t i m a t e o f 15,100 m e t r i c t o n s o f manganese (Mn) ( M o r t v e d t ) i s c o n s i d e r a b l y h i g h e r t h a n


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F r i t ' s e s t i m a t e o f 13,100 t o n s f o r b o t h 1984 a n d 1985. S o u r c e s o f manganese a r e b a g h o u s e d u s t s , s c r u b b e r s l u d g e s , and s l a g s p r o d u c e d d u r i n g t h e p r o d u c t i o n o f f e r r o m a n g a n e s e , s i l i c a manganese, o r e l e c t r o l y t i c manganese d i o x i d e , a n d t h e f i n e p a r t i c l e s p r o d u c e d when t h e s e manganese a l l o y s a r e crushed and screened t o s i z e . Manganese o r e s (Mn0 ) c a n be u s e d t o p r o d u c e manganese f e r t i l i z e r p r o d u c t s , b u t t h e y must f i r s t b e r e d u c e d t o manganous o x i d e (MnO++) t o b e a v a i l a b l e f o r p l a n t uptake. Manganese p r e s e n t s a g r o n o m i c p r o b l e m s due to i t s tendency t o o x i d i z e i n t h e s o i l and r e v e r t t o manganese d i o x i d e o r some o t h e r u n a v a i l a b l e f o r m o f manganese.


2

Molybdenum. Molybdenum u s a g e i n f e r t i l i z e r s i s q u i t e l i m i t e d a l t h o u g h 30 s t a t e s r e p o r t e d d e f i c i e n c i e s i n 1966(Cunningham). Molybdenum i s r e q u i r e d b y t h e s y m b i o t i c b a c t e r i a f o u n d o n r o o t s o f legumes t h a t e n a b l e t h e p l a n t t o f i x elemental nitrogen. I t s use i s l i m i t e d by t h e s m a l l amount r e q u i r e d and, due t o t h e c o s t , i t i s o f t e n c o a t e d onto t h e seed p r i o r t o p l a n t i n g . L i t t l e molybdenum i s a p p l i e d t o t h e s o i l o r f o l i a g e , due t o i t s u n i q u e r o l e i n plant nutrition. I t i s d i f f i c u l t t o e s t i m a t e t h e usage o f molybdenum a s f e r t i l i z e r b u t i n a t y p i c a l m i c r o n u t r i e n t f e r t i l i z e r m i x t u r e , t h e molybdenum g u a r a n t e e w i l l be .005% a n d i n a m i x e d f e r t i l i z e r , t h e g u a r a n t e e w i l l b e .0005%. While t h e r e i s l i t t l e used i n m i c r o n u t r i e n t f e r t i l i z e r s , byp r o d u c t molybdenum c a n be f o u n d i n s p e n t c a t a l y s t a n d o f f grade molybdic o x i d e and s u l f a t e . Vanadium. V a n a d i u m u s e i s r a r e , a n d t h e r e i s no c o n s e n s u s among a g r o n o m i s t s t h a t s u p p l e m e n t a l a p p l i c a t i o n s o f v a n a d i u m a r e n e e d e d , a l t h o u g h some t e s t s p e r f o r m e d a t T e x a s A&M have shown t h a t v a n a d i u m a p p l i c a t i o n s b e n e f i t g r a i n a n d c o t t o n crops under drought conditions(Wendt). Zinc. Z i n c i s v i t a l i n t h e formation o f c h l o r o p h y l l and synthesis of carbohydrates. I t i s t h e most w i d e l y u s e d m i c r o n u t r i e n t , w i t h 43 s t a t e s r e p o r t i n g d e f i c i e n c i e s . Zinc i s r o u t i n e l y a p p l i e d t o c o r n , wheat, r i c e , a n d o t h e r g r a i n crops. Z i n c d e f i c i e n c i e s a r e more w i d e s p r e a d t h a n a n y o t h e r m i c r o n u t r i e n t a n d u s u a l l y a p p e a r i n s a n d y o r h i g h pH s o i l s . High s o i l phosphate l e v e l s can a l s o induce z i n c d e f i c i e n c y . I n 1984 t h e U.S. D e p a r t m e n t o f A g r i c u l t u r e r e p o r t e d 37,300 m e t r i c t o n s o f e l e m e n t a l z i n c was u s e d a s a



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f e r t i l i z e r micronutrient(Mortvedt). Frit Industries e s t i m a t e s t h a t 29,500 m e t r i c t o n s o f z i n c were a p p l i e d i n 1995. S o u r c e s o f z i n c raw m a t e r i a l s a r e : p l a t i n g wastes, baghouse dust from s m e l t e r s , e l e c t r i c a r c f u r n a c e dust from s t e e l p r o d u c t i o n , z i n c d r o s s and z i n c skimmings f r o m g a l v a n i z i n g o p e r a t i o n s , z i n c - c o p p e r baghouse dust from b r a s s a n d b r o n z e s m e l t e r s , b o i l e r a s h , and v a r i o u s s t r e a m s f r o m i n d u s t r i a l processes o r water treatment systems. Most z i n c m a t e r i a l s c o n t a i n l e a d and, i n some c a s e s , cadmium a s an i m p u r i t y due t o t h e i r o c c u r r e n c e i n t h e same g e o l o g i c a l d e p o s i t s ( L a g e r w e r f f ) o r the improved f l o w a b i l i t y of molten z i n c w h i c h has l e a d i n c l u d e d as p a r t o f t h e i n g o t b e i n g melted. P r i m e w e s t e r n z i n c i s an example o f t h i s . Z i n c c o n t a i n i n g b y - p r o d u c t s h a v i n g a low b u l k d e n s i t y o r d u s t p r e s e n t p r o b l e m s f o r u s e r s due t o OSHA r e g u l a t i o n s r e s t r i c t i n g worker exposure t o d u s t s - - e s p e c i a l l y those c o n t a i n i n g l e a d and cadmium. Mechanical conveying systems used i n the f e r t i l i z e r i n d u s t r y are t y p i c a l l y bucket e l e v a t o r s and b e l t c o n v e y o r s . Neither fine dry materials n o r s l u d g e s a r e h a n d l e d s a f e l y by t h e s e c o n v e y a n c e s . One v e r y important l i m i t a t i o n to a m a t e r i a l ' s u t i l i z a t i o n i s i t s c o n t e n t o f v e r y f i n e m e t a l l i c z i n c w h i c h w i l l o x i d i z e when exposed t o a source o f moisture, g e n e r a t i n g extreme heat. M i c r o n u t r i e n t u s a g e has l e v e l e d o f f i n r e c e n t y e a r s . The s o u r c e o f t h e f e r t i l i z e r m i c r o n u t r i e n t raw m a t e r i a l s w i l l c o n t i n u e t o be b y - p r o d u c t s . F e r t i l i z e r micronutrients a l r e a d y consume, w i t h a g r e a t b e n e f i t t o s o c i e t y , many byp r o d u c t m a t e r i a l s t h a t have no o t h e r e c o n o m i c u s e . If f u r t h e r r e g u l a t i o n p r o h i b i t s t h i s u s e , i t w o u l d d r i v e more m a t e r i a l s i n t o l a n d f i l l s o r i n t o non-economic, s u b s i d i z e d r e c o v e r y programs. The p r o d u c t i o n o f a l l c o p p e r , i r o n , and z i n c m a t e r i a l i s a l r e a d y h e a v i l y d e p e n d e n t on r e c y c l e d materials. Even i f p u r i f i e d p r o d u c t s a r e u s e d as m i c r o n u t r i e n t s , t h e i r s o u r c e w i l l c o n t i n u e t o be byproducts . As a g r i c u l t u r a l p r a c t i c e s c o n t i n u e t o e v o l v e , t h e t r e n d w i l l p r o b a b l y be t o w a r d s more s e l e c t i v e a p p l i c a t i o n o f f e r t i l i z e r s and m i c r o n u t r i e n t s . S e l e c t i v e a p p l i c a t i o n of f e r t i l i z e r s d o e s n o t mean l e s s f e r t i l i z e r o r m i c r o n u t r i e n t s w i l l be u s e d . Environmentally sensitive or marginally p r o d u c t i v e l a n d w i l l p r o b a b l y n o t be f a r m e d ; i n s t e a d t h e more p r o d u c t i v e a n d / o r l e s s e n v i r o n m e n t a l l y s e n s i t i v e l a n d


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w i l l be more h e a v i l y f e r t i l i z e d t o f e e d t h e w o r l d ' s population. F o r t h i s reason, m i c r o n u t r i e n t s w i l l continue t o be n e e d e d t o o p t i m i z e p r o d u c t i o n .


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A l s r i c h , Samual R., Scott, Walter O., Leng, Earl R., Modern Corn Production, A&L Publications, Champagne, IL 1976. Brown, A. Lloyd, Bureau, Richard G . , Giger, David R., "Flue Dusts As Zinc F e r t i l i z e r s , " California Agriculture, August, 1977. Cunningham, H.G., Micronutrients In Agriculture, "Trends i n the Use of Micronutrients", Soil Science Society of America, Madison, WI, 1982. Farm Chemical Handbook '95.Vol. 81., Meister Publishing Company, Willoughby, OH, 44094, 1995. The

F e r t i l i z e r Handbook, The F e r t i l i z e r Institute, Washington, DC, 1982.

Foth, Henry D. Fundamentals of Soil Science. John Wiley & Sons, New York, 1978. Hignett, T . P . , F e r t i l i z e r Manual, Developments in Plant and S o i l Sciences, Volume 15, Martinus Nijhoff, Dr. W. Junk Publishers, Dordrecht, The Netherlands, 1985. Lagerwerff, J . V . , "Lead, Mercury, and Cadmium as Environmental Contaminants", Micronutrients in Agriculture, Soil Science Society of America, Madison, WI, 1972 Lepp, N.W., Effect of Heavy Metal Pollution on Plants, Volume 2, Metals in The Environment, Applied Science Publishers Inc., Englewood, NJ 1981. Mortvedt, J.J. 1987. "Cadmium Levels in Soils and Plants From Long Term Soil F e r t i l i t y Experiments in The United States of America," J. Environ. Qual.,16:137-142.


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Mortvedt, J.J. 1985. "Plant Uptake of Heavy Metals in Zinc Fertilizers Made From Industrial Byproducts," J. Environ. Qual., 14:424-427.


Mortvedt, J.J., "Use of Industrial By-Products Containing Heavy Metal Contaminants in Agriculture," Residues and Effluents- Processing and Environmental Considerations, The Minerals, Metals & Materials Society, 1991.

National Agricultural Statistical Service "Track Records, United States Crop Production,", Beltsville, MD, 20705-2351, 1996. Nicholas, D.J.D., Egan, Adrian R., Trace Elements in Soil Plant-Animal Systems. Academic Press, New York, 1975. Nriagu, Jerome O., Zinc Ecological Cycling,

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Olsen, S.R., Micronutrients in Agriculture, "Micronutrient Interactions", Soil Science Society of America, Madison, WI, 1972. Page, A.L., Logan, T.J., Ryan, J.A., Land Application of Sludge, Lewis Publishers, Inc., Chelsia, MI, 1987. Russell, E.W., Soil Conditions and Plant Growth, Longman Group, Ltd., New York, 1973. Sittag, Marshall, Metal and Inorganic Waste Reclaiming Encyclopedia, Noyes Data Corporation, Park Ridge, NJ, 1980. Wendt, Charles, "TAES Research", The Cross Section, High Plains Underground Water Conservation District No.1, Lubbock, TX, May, 1991. Weiss, Stanley Α., Manganese, The Other Uses, Metal Bulletin Books Ltd., Garden City Press Limited, Letchworth, Hertfordshire, Great Britain, 1977. Wolnik,Karen, Fricke, Fred L., Braude, George L., Meyer, Milton W., Satzger, R. Duane, Bonnin, Evelyn. "Elements in Major Raw Agricultural Crops in the United States. 1. Cadmium and Lead in Lettuce, Peanuts, Potatoes, Soybeans, Sweet Corn, and Wheat," J. Agric. Food Chem., Vol.31, No. 6, 1983. In Agricultural Uses of By-Products and Wastes; Rechcigl, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1997.

By-Product Usage in Fertilizer Micronutrients - ACS Symposium Series

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