RESPONSE OF 'TEMPLE' ORANGES TO VARYING RATES OF

Transcription

1 1 FLORIDA STATE HORTICULTURAL SOCIETY, 1 even though K vlues were douled in the leves. The lowering of lef Mg, s K incresed, is n lmost exct sustitution on chemicl-equiv lent sis. The scion source hd no effect on the con centrtions of N, P, or Mg in the leves. The similrity of the minerl composition of the leves indictes tht the sme set of stndrd vlues could e used in dignostic work. The reltively smll differences in K nd C etween young- nd old-udline leves would seldom re quire specil considertion in mking n inter prettion. LITERATURE CITED 1 Clvn, E. C, E. F. Frolich, J. B. Crpenter, C. N. Roistcher, nd D. W. Christinsen Rpid indexing for exocortis of citrus. Phypthology 54: Smith, P. F Effect of potssium level nd sustrte lime on growth, fruit qulity, nd nutritionl sttus of Vlenci ornge trees. Plnt Anlysis nd Fert. Prolems 4: Citrus nutrition. Chp. 7 in Fruit Nutrition, N. F. Childers, ed. Horticulturl Pulic tions, Rutgers Univ., New Brunswick, N. J Lef nlysis of citrus. Chp. 8 in Fruit Nutrition, iid. 5. Smith, P. F., nd G. K. Rsmussen Reltion of potssium nutrition to size nd qulity of Vlenci ornges. Proc. Amer. Soc. Hort. Sci. 74: RESPONSE OF 'TEMPLE' ORANGES TO VARYING RATES OF NITROGEN, POTASSIUM, AND MAGNESIUM Dvid V. Clvert Indin River Field Lortory, IFAS Fort Pierce Astrct A fertilizer experiment ws initited in 19 on Temple' trees plnted in 1955 on Wsso fine snd to study responses to vrious rtes of nitrogen, potssium, nd mgnesium fertiliz tion. Nitrogen fertiliztion incresed yields, ut decresed fruit size, solule solids, nd cid con tent of juice. The peels of fruit from high nitrogen plots were distinctly greener nd corser thn peels of fruit from lower nitrogen plots. Incresing potssium levels incresed fruit size nd incresed the juice cid content ut decresed the Brix-to-cid rtio. Yields were significntly higher t the middle potssium rte. Mgnesium pplictions filed to produce meningful tree responses ecuse levels of Mg in the soil were dequte to mintin produc tion nd qulity. INTRODCTION The 'Temple' vriety of citrus, n excellent eting ornge, is produced primrily for the fresh fruit mrket. It is necessry to hve Florid Agriculturl Experiment Sttion Journl Series No knowledge of the effects of culturl prctices on this importnt vriety's internl nd externl fruit qulity nd yield to insure the highest pckout nd, consequently, the highest net dollr returns to the citrus grower. One fctor tht hs een shown to influence the qulity, nd hence the fresh fruit pck-out of other vrieties of citrus is fertiliztion prctice (2, 5, 6, 7, 9, 1, 11). The fertiliztion requirements of the 'Tem ple' ornge hve not een s precisely denned s other citrus vrieties such s 'Vlenci' ornge nd 'Mrsh' grpefruit. The purpose of this pper is to present the results of field fertilizer experiment with 'Temple' ornges using vrious rtes of nitrogen, potssium, nd mgnesium. Experimentl Procedure The experiment ws initited in 19 in the Indin River Field Lortory grove with 'Tem ple' trees on 'Cleoptr' mndrin rootstock plnted on Wsso fine snd in The trees were plnted on single row eds spced 3 feet prt with trees 22.5 feet prt in the rows, mking 64.5 trees per cre. The Wsso fine snd, previously clssified s Leon fine snd, is fltwoods type elonging to the soil order of Spodosols. The ph of the top 12 inches of soil in 19 rnged from 5.4 to 6.5. The surfce soil horizon vries in color from gry to drk gry with susurfce lyers grding into white snd

2 CALVERT: TEMPLES NITROGEN, POTASSIUM, MAGNESIUM 11 t 8 to 12 inches. The soil contins "spodic" horizon known s the orgnic hrdpn t depths of 24 to 3 inches which is usully underlin y fine sndy lom lyer extending to depths of 6 inches or more. The spodic horizon ws not distured to ny extent in preprtion of the single row eds for plnting. The experiment consisted of 8 fertilizer tret ments in rndomized locks with 5 replictions. Ech plot consisted of 4 trees in row with 1 uffer tree t ech end of the plot. Tretments 1, 2, nd 3 consisted of 3 rtes of fertilizer N nd Tretments 4 nd 5 consisted of the low nd high rtes of K, respectively (Tle 1). The fertilizer rtio used for Tretment 2 served s the middle rte for the N nd K vriles nd s the high rte for the Mg vrile. Tretments 6 nd 7 were included to test the possiility of using dolomitic limestone s the exclusive Mg source. Mg ws not included in the fertilizer used for Tretments 6 nd 7. During the 12-yer experimentl period, Tretment 6 plots received 4 pplictions of high-clcium limestone, while Tretment 7 plots received 4 pplictions of dolomitic limestone. The ppli ctions of limestone were mde t the 1-ton per cre rte in 19, 19, 1964, nd In these yers, plots receiving the other tretments were lso limed with dolomitic limestone t the 1-ton per cre rte. This rte ws sufficient to min tin soil ph etween 5.5 nd 6.5 in ll plots. Tretment 8 consisted of low Mg fertilizer rte with n rtio. The sources for the minerl elements used in the fertilizer mixtures were mmonium ni trte, super phosphte, murite of potsh, nd mgnesium sulfte. Trees were fertilized 3 times per yer on Octoer 2, Ferury 2, nd June 2 t the rtes nd mounts shown in Tle 1. Fertiliz tion rtes were djusted severl times s the trees grew older to recognize the spred of their roots nd s certin tree responses ecme evi dent. However, the proportionte differences in fertilizer rtios were mintined over the 12- yer period. Since 1968, the highest rte hs mounted to 248 pounds of N per cre per yer which is considerly higher thn wht hs een recommended for mture ornge trees in the Indin River re (8). All fertilizer ws dis triuted y hnd over the entire plot re, except in the pproximtely 6-foot wide strip occupied y the wter furrow. Trees were uni formly irrigted when necessry, using portle, perforted pipe. Oservtions of the condition of the trees were mde t lest once ech yer. Trunk cir cumference mesurements were tken in 19 nd gin in 1. Spring flush leves from nonering twigs were smpled in July or Au gust during severl yers of the experiment for minerl elements. Surfce soil smples (-6 Tle 1. Rtios nd pounds of N, K2, nd MgO pplied per cre per yer. No. 1 rtio N K?U MgO (ls/ A) 1 ^ N J59-19 K2 (ls/a) MgO 1 t" N K2 MgO (ls/a) 1 IS N K MgO (ls/a) N K (ls/a) MpO " " Limed with high-clcium limestone only. Limed with dolomitic limestone only.

3 12 FLORIDA STATE HORTICULTURAL SOCIETY, 1 inches) were tken ech yer for ph determin tion. In 1, the soil in the vrious plots ws nlyzed for extrctle C nd Mg s well s ph. These determintions were mde ccording to the methods of nlysis of the University of Florid Citrus Experiment Sttion (1) which included extrction with mmonium cette t ph 7.. Yield ws otined t the time of pick ing which generlly ws in lte winter ech yer. Fruit ws smpled ech yer during the first week of Jnury for qulity mesurements. Results Soil test vlues for ph, C, nd Mg deter mined on the soil smples tken in 1 re presented in Tle 2. These vlues show tht ph, C, nd Mg levels were dequte in ll experimentl plots regrdless of tretment. Plots receiving dolomitic limestone s the exclu sive source of Mg (Tretment 7) nd plots re ceiving 1 nd 3 units of Mg plus dolomitic lime stone (Tretments 8 nd 2) hd significntly higher levels of soil Mg thn plots receiving only high-clcium limestone nd no Mg in the fertilizer. The dt on the minerl content of spring cycle leves smpled from nonfruiting terminls in 1967, 1968, nd 1969 re shown in Tle 3. Tle 2. Effect of rtes of nitrogen, potssium nd mgnesium on ph nd extrctle cl cium nd mgnesium content of soil smpl ed from experimentl plots. Smples collected in 1. rtio ph C Mg (ls/a) N rte X K rte MgO rte ** 148 * Limed with high-clcium limestone only. ++ Limed with dolomitic limestone only. * Columns of mens followed y the sme letter do not differ t P =.5. Columns of mens without letters re not sttisticlly significnt. x Tretment 2 ws used 3 times in the sttisticl nlyses shown in this tle nd in the susequent tles. It served s the middle rte for the N nd K rtes nd s the high MgO rte. Tle 3. Effect of fertilizer rtes on the minerl element content of spring cycle leves of 'Temple*1 ornge trees. Dt represent 3 yer verges, rtio K rte MgO rte 8-4-lO-o, See footnotes of Tle c _Mg_ CO O r-l A fivefold increse in fertilizer N rte incresed lef N content only slightly. However, oth lef P nd K content tended to decrese mrkedly with incresing N rte. Incresing K fertilizer rte hd little effect on lef N or P content. However, incresing K in the fertilizer incresed lef K considerly, ut decresed lef C. Incresing Mg rte tended to hve little effect on lef N, P, K, nd C levels. Tretment 6 hd significntly lower Mg thn Tretments 2, 7, nd 8. In ll cses, the level of Mg in the leves ws dequte, even where only high-clcium limestone nd no fer tilizer Mg ws pplied. Tree size, mesured s trunk circumference, dimeter of folige, nd the clculted cnopy re is presented in Tle 4. Incresing N rte Tle 4. Effects of fertilizer rte tretments on height, dimeter, cnopy re, nd trunk circumference of 'Temple' ornge trees. rtio N rte K rte MeO rte ot, Trunk circumference (inches) See footnotes of Tle 2. Tree height (ft.) c Tree Tree width cnodv re (ft.) (sq. ft.)

4 CALVERT: TEMPLES NITROGEN, POTASSIUM, MAGNESIUM 13 tended to increse tree trunk circumference, tree height, nd tree cnopy re. There were no significnt size responses to the K nd Mg rte tretments. Yield dt s ffected y fertilizer tretments for the period re shown in Tle 5. The min yield response ws to N fertiliztion. Highest yield ws otined t the high N rte; ut, in only one of the 9 yers ws the difference significnt etween the high nd medium rtes. Yields in individul yers were not significntly ffected y the K rte tretments in the decde tht yields were recorded. However, sttisticl nlysis of the dt collected over the 1-yer period reveled tht the middle K rte produced significntly more thn either the low or high K rtes. Yield ws not responsive to the Mg rte or liming tretments in ny yer. Incresing rtes of oth N nd K dversely ffected oth internl nd externl fruit qulity (Tle 6). Solule solids nd cid contents de cresed with incresing N rtes. Acid content incresed nd Brix-to-cid rtio decresed con siderly with incresing K rtes. Juice con tent ws not influenced y the N nd K fertilizer tretments. Chnging the Mg levels ffected neither solule solids nor cid content of the juice. Juice content ws slightly reduced t the high Mg rte. Hevier nd lrger fruit were produced with the low N rte, slightly lighter fruit were produced with the middle N rte, nd considerly smller fruit were produced with the high N rte. The low K rte produced slightly lighter fruit thn either the middle or high K rte. The Mg rtes or liming tretments did not significntly influence the fruit weight. Color nd corseness of the fruit peel were influenced y incresing N nd K rtes s shown in Tle 6. Fruit produced t the high N rte were distinctly greener nd corser thn t the lower 2 rtes. Fruit t the high K rte were lso corser nd greener thn t lower K rte (Tle 6). Mg nd lime tretments filed to influence 'Temple' peel qulity significntly. Disscussion The results of this experiment show tht the low N rte produced lrge, well-colored fruit with high solule solids. However, yields were severely reduced t the low rte. By compromis ing slight mount in the size nd qulity, the verge production ws considerly etter t the middle N rte. In fct, production t the middle N rte ws generlly s good sttisticlly s t the high N rte nd it ws not ccompnied y the detrimentl effects on fruit size nd qul ity experienced with the high rte. It cn e stted tht the high N plots definitely received too much N, since fruit were often green nd corse nd smll sized. In generl, incresing N rte reduced cid content of the fruit. The re duction in cid content ws unexpected, since severl investigtors (6, 7, 9) hve reported Tle 5. Effect of rtes of nitrogen, potssium, nd mgnesium on yield of 'Temple' ornge trees on 'Cleoptr' rootstock plnted in rtio Boxes yer 1963 per Boxes per tree 1-yer verge c MgO rte ' " See footnotes of Tle 2.

5 14 FLORIDA STATE HORTICULTURAL SOCIETY, 1 Tle 6. Effects of fertilizer tretments on fruit weight nd juice qulity fctors. Dt represent 1-yer verges ( to ), except peel color nd corseness dt which represent one yer (196-61). rtio Juice % Brix % Acid % Brix-tocid rtio Fruit weight grms Peel color rtingy Peel corseness rting2 N rte c K rte c 1.88 c MgO rte ot, See footnotes of Tle 2. y = Key to peel color rting: 1. Full ornge peel 2. Yellow with greenish ting 3. One-hlf surfce green z = Key to peel corseness rting: 1. Fine peel 2. Norml 3. Knotty corseness incresing cid content with incresing N rte for other citrus vrieties. Perhps the reduction in cid with high N rtes cn e explined on the sis of reduction in lef K content s shown in Tle 3. Growth of trees ws gretest t the high N rte, ut trees were intensely green nd vegettive, indicting too high level of N. Smith nd Rsmussen (12) noted trees receiv ing less N hd out s high N level in the leves, ut not s mny leves were on the trees receiving the low N rtes. The 1-yer verge dt show tht the middle K rte gve slightly higher fruit pro duction thn the low nd high K rtes (Tle 5). Also, the fruit produced with the middle K rte were significntly hevier thn fruit pro duced with the low K rte (Tle 6). Acid con tent of the fruit incresed nd solule solids in the fruit remined nerly constnt s K rte incresed. At the high K rte, color nd texture qulity of the peel diminished nd weight of fruit did not increse signficntly. Potssium fertilizer definitely ws wsted t the high K rte. Considering ll fctors, the middle K rte seems to e the est recommendtion for con ditions similr to those in this experiment. The filure of 'Temple* ornges to respond to Mg pplictions my e ttriuted to n initil high Mg content of the soil. Soil test vlues for the no Mg plots reveled n verge of 148 pound of extrctle Mg per cre fter cropping for 12 yers (Tle 2). Clvert nd Reitz (3) nd Koo nd Clvert (4) hve otined similr results with other Mg rte experiments in the Indin River Field Lortory grove. The lef Mg content ws dequte to insure no Mg de ficiency symptoms on the leves. The grower would e well dvised to test oth leves nd soil for Mg in his prticulr re efore reduc ing or eliminting the Mg from his fertilizer. The middle rte of N nd K (8-4-1 fertilizer rtio) ws the most stisfctory for the produc tion of 'Temples' from n overll fruit qulity nd yield stndpoint. 'Temple' growers with tree nd soil conditions pproximtely identicl to those in this experiment my wnt to em ploy similr rte nd rtio of fertilizer to otin improved internl nd externl fruit

6 REESE: ARSENATE SPRAYS TEMPLES 15 qulity without scrificing yields. The dt o tined from this experiment consistently showed tht N ws the min fctor influencing fruit qulity nd yield, while K ssumed secondry role in ffecting these fctors. Furthermore, the results indicte tht under similr soil condi tions, the fertilizer rtio of N to K cn e chnged from 1:5 to 1:1 without mterilly influencing fruit qulity nd yield. Therefore, sed on the middle N rte presented in Tle 1 ( dt), 13-yer-old Temple' trees would require pproximtely pounds of N nd pounds of K2O per cre per yer in plntings contining 64.5 trees per cre. Summry Twelve yers of differentil fertiliztion of 'Temple' ornges with vrying rtes of N, K, nd Mg showed tht internl nd externl qul ity of this fresh fruit vriety ws ffected y rte of ppliction of oth N nd K. Incresing N levels incresed yields, decresed fruit size, nd influenced oth internl nd externl fruit qulity. Acid content of the fruit juice tended to decrese with incresing N rte. Incresing K levels incresed fruit sizes nd incresed cid content nd the middle K rte incresed yields only slightly over the 12-yer period. Vrying Mg levels filed to produce meningful tree responses ecuse levels of Mg in the soil were dequte to mintin production nd qulity. Mg content of leves nd soil ws significntly higher in plots receiving dolomitic limestone thn in plots receiving high-clcium limestone. LITERATURE CITED 1. Anderson, C. A., H. B. Grves, Jr., R. C. J. Koo, C. D. Leonrd, nd R. L. Reese Methods of nlysis. Fl. Agr. Expt. St. Project Lke Alfred. Unpulished. 2. Clvert, D. V., nd H. J. Reitz Effects of rte nd frequency of fertilizer pplictions on yield nd qulity of 'Vlenci' ornges in the Indin River re. Proc. Fl. Stte Hort Soc. : Clvert, D. V., nd H. J. Reitz, Response of citrus growing on clcreous soil to soil nd folir pplic tions of mgnesium. Proc. Fl. Stte Hort Soc. 79: Koo, R. C. J., nd D. V. Clvert Mgnesium oxides s sources of mgnesium for citrus. Proc. Fl. Stte 5 Reitz H. J Timing fertiliztion of citrus in the Indin River re. Proc. Fl. Stte Hort. Soc. 69: "6.'Reitz, H. J., nd R. R. Hunziker A nitrogen rte nd rsenic spry experiment on 'Mrsh' grpefruit m the Indin River re. Proc. Fl. Stte Hort. Soc. 74: Reitz, H. J., nd R. C. J. Koo Effect of nitro gen nd potssium fertiliztion on yield nd fruit qulity of 'Vlenci' ornges on clcreous soil. Proc. Fl. Stte Hort. Soc. 72: ir 8 Reitz H. J., C. D. Leonrd, I. Stewrt, R. C. J. Koo, D V. Clvert, C. A. Anderson, P. F. Smith, nd G. K. Rsmussen Recommended fertilizers nd nutritionl sprys for citrus. Fl. Agr. Exp. St. Bull. 536B. 9. Reuther, W., nd P. Smith Reltion of nitro gen, potssium nd mgnesium fertiliztion to some fruit qulities of 'Vlenci' ornge. Proc. Amer. Soc. Hort. Sci. 1~ Reuther, W., nd P. Smith Fertiliztion nd qulity of ornges. Citrus Mg. 15(2): Smith, P. F., nd G. K. Rsmussen Reltion of potssium nutrition to size nd qulity of 'Vlenci' ornges. Proc. Amer. Soc. Hort. Sci. 74: # 12. Smith, P. F., G. K. Scudder, Jr., nd G. Hrncir Nitrogen rte nd time of ppliction on the yield nd qulity of 'Mrsh' grpefruit. Proc. Fl. Stte Hort. Soc. 82: ARSENATE SPRAYS ON 'TEMPLE' ORANGES: RATES, TIMING, AND RESIDUES R. L. Reese Florid Citrus Experiment Sttion Lke Alfred Astrct Led nd clcium rsentes were spryed on 'Temple' ornges to determine the effects of rtes nd timing, nd the rsenic residues in the fruit. Although the present lw does not per mit the use of rsenic in ny form on 'Temples,' Florid Agriculturl Experiment Sttion Journl Series No. STSQ. led rsente is pproved for use on grpefruit. Grpefruit vrieties require s much s 1^4 pounds per 1 gllons of led rsente to reruce cid levels sufficiently for erly legl mr keting of fruit. Tests hve shown tht 'Temple* ornges require only XA pound per 1 gllons or less of either led or clcium rsente to give stisfctory reduction in fruit cidity. This reduction of fruit cidity would llow fruit to meet present mturity stndrds 2 to 4 weeks erlier thn nonspryed fruit. Arsenic mterils could e pplied in postloom or summer long with regulr spry pplictions. Excessive rtes of ppliction of rsentes led to severe rsenic