GROWING ON CALCAREOUS SOILS

Transcription

1 FLORIDA STATE HORTICULTURAL SOCIETY, 97 FIELD TESTS WITH NEW IRON CHELATES ON CITRUS GROWING ON CALCAREOUS SOILS C. D. Lonr Agriculturl Rsrch n Euction Cntr Lk Alfr n D. V. Clvrt Agriculturl Rsrch Cntr Fort Pirc Astrct In rcnt yrs, rplict fil plot tsts hv n crri out with nw iron chlts ppli to th soil roun iron-chlorotic orng trs in grovs growing on clcrous soils on Flori's st cost. A fw of th nw chlts compr fvorly with tchnicl soium frric thylnimin i- (o-hyroxyphnyl ctt) (FEDDHA) in rgrning iron-chlorotic trs on ths soils. Ths tsts inict tht th rily solul FEDDHA is still th st iron chlt currntly vill to growrs for corrcting iron ficincy of citrus growing n clcrous soils in Flori. Introuction Iron chlorosis of citrus occurr xtnsivly on oth ci n clcrous soils in Flori in th rly 9's. It ws foun in 9 tht soil ppli ction of to grms F pr tr s th iron chlt frric thylnimin ttrctt (F- EDTA) quickly corrct iron ficincy in citrus on ci soils (). Svrly iron-chlorotic trs trt with FEDTA vlop unnt loom n nw grn growth, n prouc highr yils () of ttr qulity fruit () thn similr un trt trs. Th fst ccptnc of this chlt y Flori growrs hs limint iron ficincy s srious prolm for citrus on ci soils. On clcrous soils long Flori's st cost, to grms F s FEDTA ws rquir to corrct lim-inuc chlorosis in citrus. Frric hyroxythyl thylnimin trictt (FHEE DTA) n frric ithylntrimin pntctt (FDTPA) wr ffctiv for citrus on som cl- Flori Agriculturl Exprimnt Sttions Journl Sris, crous soils whn ppli t rts of to 7 grms F pr tr (). Both chlts usully r quir to 8 months to corrct lim-inuc chlorosis. Soium frric thylnimin i-(o-hyroxyphnylctt) (FEDDHA) ppli to th soil t rts of to grms F pr tr corrct lim-inuc chlorosis in Flori citrus within 6 to 8 wks ftr ppliction on ll soils tst (). It ws succssful on svrl soils whr FDTPA n FHEEDTA ppli t 7 to grms F pr tr fil to rgrn similr chlorotic trs. Th work rport hr ws crri out in n ffort to fin nw iron chlts tht wr mor conomicl ut s ffctiv s FEDDHA for corrcting lim-inuc chlorosis in Flori citrus. Mtrils n Mthos Fiv rplict fil plot xprimnts of rn omiz lock signs wr initit y using soil pplictions of FEDDHA n svrl nw iron chlts roun F-chlorotic orng trs growing on clcrous soil. All chlts in Exprimnts,, n wr rocst in ry form. In Ex primnt, ll chlts xcpt FEDDHA wr ppli in gllons of solution pr tr. All trtmnts in Exprimnts,, n wr ppli only on tim, whn th xprimnts wr strt. In Exprimnt, th lowr rts wr ppli mor thn on tim (Tl ). Numrs or othr signtions of th chlts n rts of ppliction r givn in th pproprit tls. 'Vlnci' orng trs wr us in Expri mnts,, n, n 'Pinppl' orng trs in Exprimnt. Exprimnts n wr con uct with trs showing uniformly svr F chlorosis growing on Mrritt Isln on soil of ph 8.. Exprimnts, n wr conuct with trs showing mil to mort F chlorosis growing on Prkwoo fin sn of ph 8.. Bfor trtmnt n uring th xprimnts th trs wr visully rt for gr of F chlorosis s scri in footnots in Tls n. In Exprimnt (Tl ), th chlts GA n GA wr formultions of FEDDHA with plstic foms sign to provi slow r ls of th iron into solution. Th xprimnts wr st up s follows:

2 LEONARD AND CALVERT:IRON CHELATES Exp. Tl Trs/ Rpli F Chlorosis Dt Strt Plot ctions Rting t Strt, My 9, 96 My, 96 Dc., 96 All April, Jun, 97 All. All lf smpls nlyz for F wr thor oughly wsh in solution of Drft to rmov surfc F contmintion. F ws trmin y th ortho-phnnthrolin mtho. Chlorophyll ws xtrct with 8 prcnt cton from mcrt iscs cut from frsh lvs soon ftr smpling n th opticl nsity of th rsulting solution ws msur t 6^. Rsults Exprimnt. FEDDHA n ll of th nw F chlts, GA 78, GA 78 n GA 78, prouc complt rgrning within months whn ppli t n grms F pr tr to th soil nr trs showing svr F chlorosis (Tl ). Whn ppli t th grm F rt pr tr, non of th chlts rgrn th trs compltly, ut FEDDHA n GA 78 ruc th F chlorosis rting to vry low lvl. For ch of th chlts, lf F of th trt trs ws significntly highr thn tht of th untrt chck trs. Fiftn months ftr trtmnt, mil to mort F chlorosis h vlop on ll of th trt trs. Th untrt chck trs show svr F chlorosis through out th xprimnt. Exprimnt. Six months ftr trtmnt with th chlts, mn F chlorosis rtings covr ing ll rts of ppliction with FEDDHA, GA 78 n GA 78 wr significntly lowr thn tht of th untrt chck trs (Tl ). Two yrs ftr trtmnt, trs rciving F EDDHA or GA 78 still show significntly lss chlorosis thn th untrt chck trs. Th -yr vrg yils (96-6 through ) of th trs rciving FEDDHA or GA 78 wr significntly highr thn th yil of th untrt chck trs. Ech of th chlts significntly incrs th vrg yil ovr tht of th chcks in 96-66, ut only FEDDHA i so in Som of th chlt trtmnts improv th intrnl qulity of th fruit. Th mn Brix (pr cnt solul solis) of th juic for ll trs tht rciv ithr GA 78 or GA 78 ws sig nificntly highr thn tht for th chck trs for 96-6 n for th -yr vrg of 96-6 n (Tl ). Th rtio of Brix to ci in th juic for ll trs tht rciv FEDDHA, GA 78, GA 78, or GA 78 ws signifi cntly highr thn tht of th chck, whrs th mn prcnt ci in th juic for ll th chlts ws significntly lowr thn th chck for Exprimnt. Thr months ftr trtmnt, th rily solul FEDDHA prouc mor grning of th chlorotic trs thn ithr of th FEDDHA foms (GA n GA ), n ws lso suprior to th potssium FEDDHA (Tl ). All of th chlts gv significntly lowr F chlorosis rtings n highr lf F thn th untrt chck trs. GA ws th lst ffctiv of th chlts us. No yil t r prsnt, sinc th mn yil iffrncs wr not significnt. Exprimnt. Th trs us in this xpri mnt show lss F chlorosis for trtmnt thn thos in Exprimnts n. Nin n months ftr ppliction, th mn chlorosis rt ings of ll chlt-trt trs wr significntly lowr thn tht of th chck (Tl ). Within months, ll of th FEDDHA trtmnts signifi cntly incrs th lf iron ovr tht of th untrt chcks. RA 7 F t th lowr rts i not significntly incrs th lf F ovr tht of th chck. Mn yils of chlt-trt trs i not iffr significntly from thos of th un trt chcks for th n 97-7 crop yrs. Exprimnt. Within -/ months ftr trtmnt, ll of th trs rciving FEDDHA wr compltly grn. XD 76, XD 77 n XD 78 t th highr rts rsult in prtil rgrning ftr 8 n months (Tl 6). FEDDHA t th lowst rt gv significntly lowr F chlorosis rtings n significntly highr lf F n highr lf chlorophyll thn th highst rt of ny of th othr chlts. Lf chlorophyll ws highly corrlt with th F contnt of th lvs (Figur ). Th

3 6 FLORIDA STATE HORTICULTURAL SOCIETY, 97 Tl. Exprimnt. --Effct of F chlts on lf F n F chlorosis rting of svrly chlorotic 'Vlnci orng trs on clcrous soil*. Grins F chlorosis rting** Lf F, ppm F F pr chlt tr FEDDHA.7.7 c.7.. c 9 7 c 9 6 GA c.7 7. c GA 78. c...7 c 7 9 c 9. 7 GA c. 8. c. 6 c Non... 9 c *In th sm column, mn vlus not follow y th sm lttr iffr significntly t P =. **F chlorosis rtings s follows: = ll lvs grn;. = vry mil, to prcnt of lvs chlorotic;. = mil, to prcnt of lvs chlorotic;. = mil to mort, to prcnt of lvs chlorotic;. = mort, 6 to prcnt of lvs chlorotic;. = mortly svr, to 7 prcnt of lvs chlorotic;. = svr, 7 to prcnt of lvs chlorotic. ^Aug summr flush; Jn. z spring flush. chlorosis rting of th trs show highly sig nificnt, ngtiv corrltion with lf F (Figur ). Lf chlorophyll contnt lso show highly significnt, ngtiv corrltion with F chlorosis rting of th trs, with r = -.98, n linr rgrssion formul of Y = X, whr Y = prcnt lf chlorophyll n X = F chlorosis rting of th trs. Discussion Th F chlorosis pttrn on iniviul lvs 96 fll flush; Aug of th trs us in Exprimnts n ws rltivly svr vn whn only fw of th lvs wr chlorotic. Thus, th prcntg of Fchlorotic lvs rflct th ovr-ll yllownss or grnnss of th tr, n l to option of th F chlorosis rting systm scri in th scon footnot of Tl. All of ths trs show svr F chlorosis (rting of.) t th strt of Exprimnts n. Th F chlorosis pttrn on iniviul lvs of th trs us in Exprimnts, n vri

4 LEONARD AND CALVERT: IRON CHELATES 7 Tl. Exprimnt. --Effct of F chlts on F chlorosis rting n yil of mortly chlorotic 'Vlnci orng trs on clcrous soil*. Yil pr tr, oxs F chlorosis rting' -yr F chlt** mn GA GA GA FEDDHA Non N.S. th sm column, mn vlus not follow y th sm lttr iffr significntly t P =. **Ech F chlt ws ppli t rts (, n gm F pr tr). Dt in this tl r vrgs of ll rts for ch chlt. Chlorosis rtings s follows: = ll lvs grn, = slight chlorosis on fw scttr lvs; = mort chlorosis, rltivly mil symptoms gnrl ovr th tr; = svr chlorosis gnrl ovr th tr. from rltivly mil to svr whn thr ws n rgrn y FEDDHA rmin grn for high prcntg of chlorotic lvs on th tr. out on yr. F chlorosis thn gn to ppr Hnc th prcntg of lvs showing som F gin on scttr lvs n incrs with tim, chlorosis i not rflct th ovr-ll yllownss or Svrl of th chlts iscuss hr, inclugrnnss of th tr. This l to option of th ing GA 78, GA 78 n GA 78 compr F chlorosis rting systm scri in th thir fvorly with FEDDHA whn ppli to svfootnot of Tl. Sinc n F chlorosis rting rly F-chlorotic trs t th rt of or of. rquir only "slight chlorosis on fw grms F pr tr. FEDDHA n GA 78 gv scttr lvs," such tr woul vry milly ttr rsults thn GA 78 or GA 78 whn chlorotic n show consirly lss yllow color ppli t grms F pr tr (Tl ). RA thn tr rt. in Exprimnts n. 7 F ws lss ffctiv thn FEDDHA on Th t rport ov show tht svrly mortly F-chlorotic trs. Th FEDDHA F-chlorotic citrus tr on clcrous soil tht h slow-rls fom formultions wr lss ffctiv

5 8 FLORIDA STATE HORTICULTURAL SOCIETY, 97 Tl. Exprimnt. Effct of F chlts on intrnl qulity of fruit from mortly chlorotic 'Vlnci orng trs on clcrous soil*. Brix Rtio Aci, F -yr mn Brix/ci prcnt chlt** & GA GA GA FEDDHA Non *In th sm column, mn vlus not follow y th sm lttr iffr significntly t P =. **S scon footnot in Tl. thn th quickly solul FEDDHA (Tl ). Thr pprs to littl chnc tht ny of ths nw chlts will us commrcilly un lss on or mor of thm () prov to mor ffctiv in corrcting lim-inuc chlorosis in crtin crops or unr crtin conitions thn FEDDHA, or () cn sol t lowr pric thn FEDDHA n still rtin comprl ffctivnss in th fil. At this tim, th quickly solul FEDDHA is still th most ffctiv F. o oc i x Y =.9-. X F IN LEAVES (ppm) ~l F IN LEAVES (ppm) Figur. Linr rgrssion curv for F n prcnt chlorophyll in lvs. Figur. Linr rgrssion curv for F in lvs n F chlorosis rting of trs.

6 LEONARD AND CALVERT: IRON CHELATES 9 Tl. Exprimnt. --Effct of F chlts on lf F n F chlorosis rting of fvlnci orng trs on clcrous soil*. Grms F chlorosis rting** Lf F, ppm F chlt F pr tr Dc. 96 Mr. 966 Jn. 967 Dc. 96 Spt. 966 FEDDHA GA... 7 GA... 8 c K FEDDHA..9 c. 7 8 Non N.S. N.S. *In th sm column, irn vlus not follow y th sm lttr iffr significntly t P =. **S thir footnot, Tl. chlt vill to growrs for corrcting F ficincy of citrus growing on clcrous soils in Flori. K F-EDDHA n FEDDHA (Squstrn 8- F) us in th xprimnts rport hr. LITERATURE CITED Acknowlgmnts Prt of th work rport hr ws support y grnts from Gigy Agriculturl Chmicls n Dow Chmicl Compny. W lso thnk Dow Chmicl Compny for supplying th F chlts XD 76, XD 77, XD 78, XD 78.-L, n FHEEDTA (F Vrsn-ol), n Gigy Agri culturl Chmicls for supplying th F chlts GA 78, GA 78, GA 78, GA, GA,. Lonr, C. D. n Ivn Stwrt. Chlt iron s corrctiv for lim-inuc chlorosis in citrus. Proc. Fl. Stt Hort. Soc. 66: Sits, J. W., C. D. Lonr n Ivn Stwrt. Citrus fruit qulity s ffct y iron ficincy n its corrction. Annul Rport, Fl. Agr. Exp. St. p Stwrt, Ivn n C. D. Lonr. Iron chlorosis its possil cuss n control. Citrus Mgzin () -.-. Jun 9.. Stwrt, Ivn n C. D. Lonr. Chlt iron stuis. Annul Rport, Fl. Agr. Exp. St. p Stwrt, Ivn n C. D. Lonr. Us of chlts in citrus prouction in Flori. Soil Sci. 8 (l):

7 FLORIDA STATE HORTICULTURAL SOCIETY, 97 Tl. Exprimnt. Effct of F chlts on lf F n F chlorosis rting of mortly chlorotic 'Vlnci orng trs on clcrous soil*. F chlt Grms F ppli pr tr Apr. 969 Mr. 97 Apr. 97 F chlorosis My 969 Jn. 97 rting** F. 97 Lf Aug. 969 F, ppm Aug. 97 Non..6.6 c 8 c RA 7 F..7.7 c RA 7 F c RA 7 F FEDDHA.. 6 FEDDHA FEDDHA 8.. c. c 8 N.S. *In th sm column, mn vlus not follow y th sm lttr iffr significntly t P =. **S thir footnot, Tl.

8 LEONARD AND CALVERT: IRON CHELATES Tl 6. Exprimnt.--Effct of 6 F chlts on lf F, lf chlorophyll n F chlorosis rting of svrly chlorotic 'Pinppl orng trs on clcrous soil*. 97 spring flush Julv 97 F chlt Grins F pr tr Oct. F chlorosis rting** 97 F. 97 July 97 F in lvs ppm Chlorophyll in lvs prcnt XD c c. c..6 c.9.. c c 6 8. f..6 6 XD c.6 c.6.6. c f XD c..8.6 c c f.. XD 78.-L c c c c. cf.9 cf.9 f 6 FHEEDTA c c c.8 f.9 f. cf.9 f FEDDHA Non (Chck) f *In th sm column, mn vlus not follow y th sm lttr iffr significntly t P =. **S scon footnot, Tl.