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Plant a nd So il 113, 271-274 (1989)9 Kluw er Academ ic Publishers PLSO 7672

U pta ke and distribution of copper and zinc by soybean and corn from soiltreated with sewage sludgeM . R . R E D D Y , D . L A M E C K a n d M . E . R E Z A N I ADe partm ent o f Plan t Science and T echnology, Nor th C arol ina Agricu l tura l and Technical S ta te University ,Greensboro, N C 27411, U SAReceived 29 Ja nua ry 1988. RevisedOctob er 1988

Ke y words : co rn , Cu up take , s ewage s ludge , soybean , Z n up takeAbstract

A f ie ld s t u d y w a s c o n d u c t e d t o d e t e rm i n e u p t a k e a n d d i s tr i b u ti o n o f C u a n d Z n b y s o y b e a n [Glycine m ax(L . ) Merr . ] and cof 'n ( Z e a m a y s L . ) g rown on E non s andy loam ( f ine , m ixed , the rm ic U l t i c Hap luda l f s ) ,t r ea ted w i th 0 , 25 , 50 , and 100 M g ha-~ o f s ewage s ludge each year . 'Ra nso m ' soybean s were g rown the f i r styear and 'FC X ' co rn was g row n in the s am e p lo t s to m atu r i ty the s econd year . In genera l , s ludge s ign if i can t lyincreased g ra in y ie ld o f soybeans and co rn . Copper concen t r a t ion in soybean s eed was h igher than in l ea fand s tem , bu t Z n concen t r a t ion was lower in the s eed than in the o ther t i s sues , under s ludge t r ea tm en t .Co ppe r in co rn l e a f inc reased m ore th an in s tem and g ra in as the r a te o f s ludge add i t ion inc reased . Z incincreased in co rn l ea f and s tem as the r a te o f s ludge inc reased , bu t Z n in g ra in was no t a f f ected .

IntroductionSludge suppl ies essent ial p lant nutr ients includ-i ng C u a n d Z n a n d i m p r o v e s a g r o n o m i c p r o p e r t ie s

of the soi l (Eps tein , 1975) . Pro ble ms are also asso -c ia ted w i th inc reased l eve l s o f som e s ludge bo rnem eta l s such as Cu and Z n in so i l wh ich r esu l t inphy to tox ic i ty (Chaney , 1984) . Acc um ula t ion o fm e t a l s b y c o r n a n d s o y b e a n s o n s l u d g e - a m e n d e dsoi ls is af fected by soi l pH (Sterr i t t and Les ter ,1980) , ca t ion exchange capac i ty (CAST , 1980) ,a n n u a l m e t a l a d d i t i o n s ( H e c k m a n et al., 1987),c u m u l a t i v e m e t a l a d d i t io n s ( S o o n et al., 1980), in-t e r ac t ions w i th o ther m eta l s , and m a cronu t r i en t s inthe so il and w i th in the p lan t (F oy et al., 1978). Pietze t a l . , (1983) repor ted s ignif icant increases in to talp l a n t u p t a k e o f Z n b y c o r n g r o w n i n s ew a g e sl u dg e -t r ea ted so i l . Heckm an et al., (1987) repor ted thatd iges ted s ludge l inearly inc reased sho o t m eta l con-c e n t r a ti o n s o f Z n a n d C u b y s o y b e a n . E x c e ss iv eam oun ts o f s ludge can supp ly exces s ive nu t r i en t sfo r c rop p roduc t ion , r educ ing y ie lds and lower ingcrop qual i ty (Eps tein , 1973) .

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D a t a o n t h e a c c u m u l a t i o n o f C u a n d Z n i na g r o n o m i c a l l y i m p o r t a n t c r o p s g r o w n o n s l u d g eam ended P iedm ont so il i s r a ther l im i ted . Ob jec t ivesof th is fie ld inves t igat ion were (1) to determ ine th eef fec t o f d r ied s ewage s ludge on y ie lds o f soyb eans[Glycine max (L . ) merr] and corn ( Z e a m a y s L .)g rown on a E non so i l and (2 ) to de te rm ine theu p t a k e a n d d i s t ri b u t io n o f C u a n d Z n b y s o y b e a nand co rn g rown on so i l t r ea ted w i th s ludge .

Materia ls and methodsT h e f ie ld s tu d y w a s c o n d u c t e d o n a n E n o n s a n d y

loam ( f ine , m ixed , the rm ic U l t i c Hap luda l f s ) loc -a t e d i n G u i l d f o r d C o u n t y , N o r t h C a r o l i n a . T h esoi l character is t ics were: pH 6.5 (1 :1 in water) ,o r ga n ic m a t t e r 1 .8 5 % , C E C 8 . 7 8 cm o l ( + ) k g - t ,c l ay 14%, s i l t 7%, and s and 79%. Ind iv idua l p lo ts ize was 2 x 6 m. The soi l wa s disked, and m uni-c ipa l d ry s ewage s ludge f rom W ins ton -Sa lem , N . C .was added a t 0, 25 , 50 , and 10 0M gh a - t , on a d ryweigh t bas i s (105C) in a r andom ized b lock des ign

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272 Short communicationwith 4 replications. The chemical composition ofthe sludge was N 21g kg -l, P 10.1gkg -~, K0.7gk g -~, Fe 4930mgkg -t, Mn 199mgkg -~, Zn735 mg kg -l, Cu 252 mg kg- ~and Cd in trace quan-tity. After sludge incorporation to 25 cm with arototiller, 6-m long rows and 67 cm apart, of ino-culated soybeans (cultivar Ransom) were planted.Soybean population was 266,667 plants per hec-tare. The crop was grown under rainfed conditions.The following year, sludge was again applied atrates and by methods specified earlier. Then corn(variety FCX 717) rows 6-m long and 67 cm apartwere planted in the plots. The corn stand was93,333 plants per hectare.

Whole plant soybean samples from each treat-ment were collected at full bloom and seed wascollected at harvest for Cu and Zn-analysis. Thewhole shoots were separated into leaves and stems.The samples were washed with tap water, rinsedwith deionized water, and dried at 70 ~ in a forceddraft oven for 48 hours. The seed weight from thetwo center rows of each plot was a measure ofsoybean yield. All plant tissue samples were groundseparately in a stainless steel Wiley mill to pass a20-mesh screen and stored in plastic bags for analy-sis. Corn ear leaf samples from each treatment atsilking were collected for analysis. At maturity,grain and stem samples were collected from the twocenter rows. The corn tissue samples were preparedusing similar procedures as stated for soybean tiss-ue. Corn yields were measured on each plot byharvesting the two center rows.

Tabl e 1 . E f f e ct o f a n n u a l s l u d g e r a te o n s o y b e a n a n d c o r n g r a i ny i e l d

S l u d g e r a t e G r a i n y i e ld a( M g h a i ) ( k g h a - i )S o y b e a n

0 2 ,9882 5 3 , 6 0 05 0 3 , 8 4 9

1 0 0 4 , 5 5 0C o r n

0 3 ,4072 5 4 , 5 1 85 0 6 , 4 6 4

100 5 ,982a R e g r e s s i o n e q u a t i o n s : S o y b e a n , y = 3 0 9 2 + 1 5 . 0 x ,r 2 = 0 . 5 5 * * ; c o r n , y = 3 2 2 0 + 8 6 . 5 x - 0 . 5 8 3 x 2 ,r 2 = 0 .46* * .

To determine the metals in soybean and corntissue, 1.0 g of plant tissue was digested with 10 mLof concentrated HNO 3 and 3 mL perchloric acid for3 hours (AOAC, 1980). The residue was dissolvedin 5mL of 16molHC1L -t and diluted to 50mLwith deionized water. The extracts were assayed forCu and Zn by atomic absorption spectrophotome-try. All analyses were conducted in triplicate. Thedata were analyzed using the regressionprocedures. The relationships between the grainyield, metal concent ration of grain, stover, and leaf,and amounts of sludge borne metals added weredetermined by linear and quadratic regressionanalysis of the data.

Result s and d iscuss ionGrain yield

Soybeans and corn grown on sludge amendedsoil produced significantly higher grain yield thanthe soybean and corn grown on control plots(Table 1). Grain yields under sludge treatmentswere higher than yields obtained with standardapplication of fertilizer on this soil (unpublisheddata from a related study). Higher yields withsludge treatment could be at tributed to higher levelof available N, P, K and micronutrients, or toimproved soil physical properties from the additionof sludge. These observations are in agreement withthe findings of Epstein, (1975) who attributed thebeneficial effects of sludge to its plant nutrients andimprovement of soil physical properties. Soybeanyield was highest at 100Mgha -~ sludge addit ion,and the response was linear. Corn grain yield washighest at 50 Mg ha-1 sludge rate and the responsewas quadratic. Yield increase was greater for cornunder sludge treatment. The reduction in corn yieldat 100Mgha I sludge rate could be attributed toexcessive supply of nut rients by sludge. No visiblephytotoxic symptoms were observed due to ap-plication of sewage sludge.

SoybeansCopper concentration in leaf, stem, and seed of

the soybean increased as the rate of sludge appliedCu increased (Tables 2 and 3). Concentration o f Cu

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Table 2. Effects of sludge borne Cu and Zn on Cu and Znconcentration in soybean and corn (mg kg- ~)Annual sludge rate Leaf Stem G rain(Mgha - t )Soybeans

02550

100

02550

100Corn

050I00200

050

100200

Cn14.4 11.4 19.914.5 11.9 20.015.1 12.8 20.917.9 13.6 24.0

Zn79.0 26.0 49.095.0 52.0 58.0

148.0 61.0 62.0173.0 129.0 72.0

Cn13.0 5.0 1.016.0 7.0 2.017.0 8.0 2.022.0 7.0 2.0

Zn30.0 27.0 28.037.0 36.0 27.045.0 44.0 27.039.0 59.0 25.0

a Sludge rate for soybean on annual basis and the rate for cornwas cumulative sludge applied.

in seed was 20 and 24 mg kg ~at 0 and 100 Mg ha-sludge rate, respectively. This is higher than theconcentration in leaf (14-18mgkg -~) and stem

S h o r t c o m m u n i c a t i o n 273(ll-14mgkg l). This suggested that seed accu-mulated greater amounts of Cu than other tissues.Although the Cu concentration in soybean tissueincreased under sludge treatment, the change inconcentrations were relatively low. As for theavailability of Cu in soil, it increased with increasedrate of sludge treatment (unpublished data fromthis study). Lower concentration of Cu in aboveground tissue could be attributed to strong chela-tion of Cu in the root cell sap, and a much smallerportion of the absorbed Cu being translocated toshoots than of Zn (Chaney, 1984). Copper con-centration observed in soybean tissue in this studyis in the range of Cu concentration normally foundin soybeans (Wolnik e t a l . , 1983).

Zinc concentration increased in the leaf, stemand seed of the soybean (Tables 2 and 3) withincreasing sludge rate. Leaf and stem Zn concentra-tions exhibited significant quadratic relationshipswith rates of the sludge whereas seed Zn concentra-tions showed a linear relationship. Heckman e t a l .(1987) while working with soybeans on Ultisolsfound similar relationships. The concentration ofZn in the leaf was 79 and 173mgkg l at 0 and100Mgha -l sludge treatment, respectively. Thiswas higher than concentration in stem (26-129 mg kg- l ) and seed (49-72 mg kg- l ) (Table 2).This indicates that leaves accumulated more Znthan other tissues. Zinc concentration in the leaftissue of soybean in this study is above the range o f

Table 3. Variables related to tissue concentration and up take of Cu and Zn in soybean and corn tissueVariables ~ Regression analysisbDependent Independent Equation r 2SoybeanLeaf Cu sludge-appl CuStem Cu sludge-appl CuGrain Cu sludge-appl CuLeaf Zn sludge-appl ZnStem Zn sludge-appl ZnGrain Zn sludge-appl ZnCornLeaf Cu sludge-appl CuStem Cu sludge-appl CuGrain Cu sludge-appl CuLeaf Zn sludge-appl ZnStem Zn sludge-appl Zn

y = 14.4 -- 0.0053 x + 0.000 4x 2y = 11.4 + 0.0 227xy = 19.9 -- 0.0033 x + 0.00048 x 2y = 73.7 + 1.54x - 0.005 3x 2y = 28.6 + 0.52 1x + 0.004 7x 2y = 50.5 + 0.220x

y = 13 .5 + 2. 00xy = 5.51 + 1.76x - 0.34 8x 2y = 1.43 + 0.772x -- 0.147x 2y = 29.0 + 0.473 x - - 0.0037x 2y = 27.6 + 0.315x

0.42*0.27*0.29*0.59**0.89**0.52**

0.55**0.31"0.38*0.77**0.64**

a Metal levels were expressed as mg kg- t in tissue and kg ha-~ sludge applied.b ,,** significant at the 0.05 and 0.01 levels of probability, respectively.

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2 7 4 S h o r t c o m m u n i c a t io nZ n c o n c e n t r a t i o n n o r m a l l y f o u n d i n s o y b e a n s( W o l n i k e t a l . , 1 98 3) . S e e d a c c u m u l a t e d r e l a t iv e l yl e ss Z n t h a n t h e o t h e r t i ss u e s.

C o r n

T h e C u c o n c e n t r a t i o n o f th e c o r n l e a f i n c r e as e dl i n e a r l y a s t h e r a t e o f sl u d g e i n c r e a s e d ( T a b l e s 2a n d 3 ). T h e r e l a t i o n s h i p b e t w e e n a d d e d C u a n d t h eC u c o n c e n t r a t io n o f c o r n s t o v er a n d g r a in w a sq u a d r a t i c . T h e C u c o n c e n t r a t i o n i n c o r n g r a i n r a n -g e d f r o m 1 t o 3 m g k g - J w i t h a n a v e r a g e o f a p -p r o x i m a t e l y 2 m g k g - ] . T h i s o b s e r v a t io n s u p p o r t st h e f i n d i n g s o f S o o n e t a l . ( 1 9 8 0 ) w h o r e p o r t e d as i m i l a r c o n c e n t r a t i o n o f C u i n c o r n g r a i n u n d e rs l u d g e t r e a t m e n t . T h e C u c o n c e n t r a t i o n o f v a r i o u st i ss u e s o f c o r n d i f f e r e d s ig n i f i c a n tl y ( T a b l e 2 ) . L e a fC u w a s i 3 a n d 2 2 m g k g -~ a t 0 a n d 2 0 0 M g h a -~s l u d g e t r e a t m e n t , r e s p ec t iv e l y . T h i s c o n c e n t r a t i o nw a s h i gh e r t h a n s t e m ( 5 - 8 m g k g - 1 ) a n d g r a in ( 1 -2 m g k g - l ) . T h i s s u g g e s t s t h a t l e a f ti ss u e s h o w e d at e n d e n c y to a c c u m u l a t e m o r e C u f r o m s l u dg e t h a no t h e r t i ss u es . C o p p e r c o n c e n t r a t i o n o f g r a in w a st h e l o w e s t a m o n g t h e t is s u e s. R e l a t i v e l y l o w c o n -c e n t r a t i o n s o f C u i n c o r n t i ss u e c o u l d b e a t t r i b u t e dt o s t r o n g c h e l a t i o n o f C u i n th e r o o t c e ll s a p a sd i sc u s se d a b o v e . C o p p e r c o n c e n t r a t i o n f o u n d i nt h e c o r n g r a i n i n t h is s t u d y i s w i t h i n t h e l i m i t s o f C uc o n c e n t r a t i o n n o r m a l l y f o u n d i n c o r n ( K i n g a n dG i o d a n o , 1 9 8 6 ) .

Z i n c c o n c e n t r a t i o n i n c r e a se d ( T a b l e s 2 a n d 3 ) i nt h e l e a f, a n d s t e m o f t h e c o r n a s a r e s u l t o f s l u d g ea d d i t i o n . T h e s e r e s u l ts a r e c o n s i s t e n t w i t h t h e f in d -i n gs o f H e m p h i l l e t a l . , ( 1 9 8 2 ) w h o r e p o r t e d i n -c r e a s e d l e a f t is s u e Z n u n d e r s l u d g e tr e a t m e n t . T h eZ n c o n c e n t r a t i o n o f c o r n g r a i n d id n o t c h a n g es i g n i f ic a n t l y w i t h s l u d g e a d d i t i o n ; t h e r e f o r e , r e -g r e s si o n e q u a t i o n f o r g r a i n d a t a is n o t p r e s e n t e d i nt h e ta b l e . C o n c e n t r a t i o n o f Z n i n l e a f w a s f o u n d t ob e 3 0 m g k g - ~, f o r t h e c o n t r o l a n d 4 5 m g k g - ~ f o r1 0 0 M g h a -~ s l ud g e t r e a tm e n t . S t e m Z n w a s2 7 m g k g - ~ f o r th e c o n tr o l a n d 5 9 m g k g ~ f o r

2 0 0 M g h a - l s lu d g e t r e a t m e n t . C o n c e n t r a t i o n o fZ n i n g r a i n w a s 2 8 m g k g - 1 f o r t h e c o n t r o l a n d2 5 m g k g - 1 f o r 2 0 0 M g h a - ~ s lu d g e t r e a tm e n t . T h i si n d i c a te d t h a t l e a f a n d s t e m h a v e a t e n d e n c y t oa c c u m u l a t e a g r e a t e r a m o u n t o f sl u d ge b o r n e Z n .Z i n c c o n c e n t r a t i o n f o u n d i n t h e c o r n g r a i n i n th i si n v e s ti g a t io n i s w i t h i n t h e r a n g e o f Z n c o n c e n t r a -t io n n o r m a l l y f o u n d i n c o r n ( K i n g a n d G i o r d a n o ,1986).

AcknowledgementsG r a t i t u d e i s e x t e n d e d t o J o s e p h B r y a n t , a n d

M a r y S h a n k s f o r t h e ir t ec h n i c al h e l p a n d t o D r .F i e l d s G u n s e t t f o r s ta t i s ti c a l a n a l y s i s. T h e f i n a n c i a ls u p p o r t t o c o n d u c t t hi s w o r k w a s g r a n t e d b y U S -D A - C S R S t h r o u g h t h e O f fi ce o f A g r i c u l t u r a l R e -s e a r c h , N o r t h C a r o l i n a A g r i c u l t u r a l a n d T e c h n i c a lS t a te U n i v e r s i ty , a n d i s v e r y m u c h a p p r e c i a t e d .

ReferencesAssociation o f Official Analytical Chemists 19 80 Methods.Analy. A ssoc. Official Analy. C hem . AOAC., W ashington,D.C . 3.007B. p 31.Chaney R L 1984 In Proc. Pan Am . Health Organi. Wo rkshopon the Internat. Transp. Utilization or disposal of sewagesludge.Council for Agricultural Science & Tec hnolog y 1980 Cou ncil forAgric. Sci. & Technol. Report no. 83, Am es, Iowa.Epstein E 1973 Proc. Joint Con f. Recycling M unicipal SludgesEffluents Land. pp 67-73.Epstein E 1975 J. E nviron . Qu al. 4, 139-142.Foy C D et al . 1978 Annu. Rev . Plan t Physol. 29, 511-566.Heckman J R et al . 1987 J. E nviron . Qua l. 16, 113-117.Hemph ill D D Jr. et al . 1982 J. Environ. Qua l 11,191-196.King L D and Giodano P M 1986 Southern Cooperative SeriesBulletin 314. pp 21 -29. North Car olina State University,Raleigh, NC.Pietz R Ie t al . 1983 J. E nviron . Qua l. 12, 463-467.Soon Y K et al . 1980 J. E nviron . Qua l. 9, 497-504.Sterritt R M and Lester J N 1980 A review. Sci. Total Environ .16, 55-90.Wolnik K A et al . 1983 J. Ag r. Food C hem . 31, 1244-1249.