EM 9013-E October 2010 Breroot Shde, Flowering, nd Fruit Trees (Willmette Vlley) J. Owen, D. Sullivn, D. Horneck, nd J. Hrt Summry Preplnt nutrient ppliction ph djustment Apply lime or elementl sulfur to djust soil ph to the trget of 5.5 to 6.5. Lime nd elementl sulfur re slow-cting, so pply 6 to 12 months hed of plnting when fesible. See pges 4 5. Phosphorus (P) Apply P if the Bry P1 soil test is less thn 35 ppm. See pge 3. Potssium (K) Apply K if soil test K is less thn 200 ppm. See pge 4. Clcium (C) If not supplied vi lime, pply C if soil test C is below 1,000 ppm (5 meq/100 g soil). See pge 5. Mgnesium (Mg) If not supplied vi dolomitic lime, pply Mg if soil test Mg is below 100 ppm (0.8 meq/100 g soil). See pge 5. Shde nd flowering trees for breroot sles throughout the United Sttes re grown in Oregon s Willmette Vlley counties of Wshington, Multnomh, Clckms, Ymhill, Mrion, Polk, Benton, nd Linn. This region receives, on verge, 35 to 40 inches of nnul precipittion, most of which flls from November through April. Soil textures rnge from sndy lom to cly lom. More thn 1,500 species nd cultivrs of ornmentl nd fruit trees re grown from tissue culture plntlets or grfted onto rootstock. In lmost ll cses, trees re grown from single bud occurring on 1-yer-old liner. This bud is grown into whip or brnched tree over 1- to 4-yer production cycle (Figure 1). Shde or flowering trees hve one to three growth flushes, continuous or episodic, to produce 4- to 8-foot whip or brnched tree of 3 4- to 2-inch cliper. Shde tree qulity nd grde re bsed on height, cliper, root structure, nd brnch structure or tree form. Consumers judge trees bsed on esthetics t time of purchse; therefore, uniform shpe, qulity roots, nd cceptble color re necessry to produce mrketble product. Annul nutrient ppliction Nitrogen (N) Apply up to 120 lb//yer. Apply in split (multiple) pplictions from Februry to June. Apply no more thn 60 lb N/ per ppliction. Increse efficiency (reduce N ppliction rte) by pplying to the root zone vi bnding, side-dressing, or fertigting. Monitor soil nitrte-n in selected fields to refine N fertilizer rtes. See pges 2 3. Sulfur (S) Apply t lest 20 lb S//yer. See pge 5. Figure 1. Breroot shde tree whips. Oregon Stte University 1 Jim Owen, Extension horticulturist; Dn Sullivn, Extension soil scientist; Don Horneck, Extension soil scientist; nd John Hrt, Extension soil scientist; ll of Oregon Stte University.
To ensure tht trees rech desired grde within n cceptble period of time, trees must be dequtely supplied with nutrients, s well s intensely mnged vi root nd shoot pruning. Shde tree growth nd qulity respond strongly to nitrogen supply nd soil ph. Other nutrients (phosphorus, potssium, mgnesium, sulfur, nd micronutrients such s iron or mngnese) sometimes limit production of sleble trees. Keep in mind tht other limittions to tree growth (weeds, insects, diseses, or wter stress) cnnot be overcome by the ddition of nutrients. To dte, nutrient mngement guidelines for shde tree production in Oregon hve not been published by the Oregon Stte University Extension Service becuse of lck of cler nd relible dt. This guide cn serve s strting point for development of nutrient mngement guidelines for Oregon growers. Recommendtions in this guide re bsed on reserch performed in the Willmette Vlley with other cropping systems nd on current nutrient mngement prctices of breroot shde tree growers. We will continue to conduct reserch nd extension ctivities to investigte the effects of nutrient mngement prctices on shde tree growth nd qulity nd to improve nutrient use efficiency. Soil physicl fctors such s depth, texture, wterholding cpcity, nd dringe ffect the soil s bility to store nd supply nutrients for tree production. These fctors re the result of inherent soil chrcteristics nd of recent mngement prctices such s equipment trffic, tillge, nd crop rottion. Soil mps, vilble from the Nturl Resources Conservtion Service or privte consultnts, provide site-specific soil informtion. Prctices tht improve soil physicl condition encourge greter root development, thereby incresing nutrient uptke. The recommendtions in this guide for ppliction of soil mendments (for ph djustment) nd immobile nutrients re bsed on preplnt soil test (0 12 inch depth). Collect composite soil smple consisting of 20 or more soil cores from ech mngement unit (field or portion of field tht cn be fertilized seprtely). Soil test interprettions in this guide re vlid only when the soil testing lb performs tests following the nlysis procedures given in Tbles 1, 2, 3, nd 5). Timing of nutrient ppliction The gol of nutrient mngement is to mtch crop need or uptke with the supply of redily vilble nutrients in the soil solution. Decisions bout timing of nutrient ppliction re bsed on the mobility of plnt-vilble nutrient forms in soil. Soil mendments to djust ph The trget ph for most shde tree species grown in the Willmette Vlley is 5.5 to 6.5. If needed, soil ph cn be rised by liming (to reduce cidity) or reduced by elementl sulfur ppliction (to increse cidity). These mendments re slow-cting nd immobile; therefore, they must be pplied before plnting nd tilled into the soil. Immobile nutrients Most nutrients (phosphorus, potssium, clcium, mgnesium, nd most micronutrients) do not move redily in the soil. Supply of these nutrients is ssessed by preplnt soil testing. Fertilizers supplying these nutrients re most effective when pplied nd incorported by tillge before plnting. Preplnt nutrient ppliction rtes given in this guide re considered dequte for 2- or 3-yer production cycle. After plnting, subsequent pplictions of these nutrients (top-dress or fertigted) ffect only smll volume of soil ner the ppliction site. Mobile nutrients Plnt-vilble forms of N nd S nitrte-n (NO3) nd sulfte-s (SO4) move redily through the soil with rin nd irrigtion wter. Recommendtions for these nutrients re bsed on nnul plnt uptke needs, not on soil test dt. Apply N nd S fertilizers ech yer to meet crop needs. Nitrogen (N) N sources Nitrogen is supplied to trees from the soil, irrigtion wter, conventionl fertilizers, mnure, compost, nd/or crop residues. Conventionl fertilizers such s ure provide redily vilble forms of N nd re used in the Willmette Vlley to supply N for ornmentl tree production. To dte, slow- nd controlled-relese N products hve not been shown to be dvntgeous to conventionl fertilizer products under Willmette Vlley conditions. N rte Bsed on grower experience nd reserch results, nnul ppliction of 120 lb N/ is usully dequte to produce high-qulity trees. Timing of N fertilizer ppliction Most growers pply N in two or three pplictions tht occur during lte winter (Februry to April) nd spring (My to June). Split, or multiple, pplictions of N fertilizer ensure n dequte mount of vilble N throughout the growing seson. Dividing the pplictions of N fertilizer is most beneficil on sndy, excessively drined soils (NRCS Hydrologic Clss A) nd on poorly drined soils (Hydrologic Clss D). Both of these soil types re highly susceptible to N loss. On Clss A soils, N is lost vi leching. On Clss D soils, N is lost vi tile drins, runoff, nd denitrifiction. Method of N fertilizer ppliction Most growers pply N by brodcsting (eril or trctor spreder). For brodcst ppliction, Willmette Vlley nursery growers typiclly pply no more thn 60 lb N/ in one ppliction. 2
In-row fertilizer ppliction cn be used to produce high-qulity trees with lower N fertilizer ppliction rtes. With in-row ppliction, the gol is to fertilize only the root zone of the trees, leving the re between rows unfertilized. N fertilizer cn be delivered to the row vi bnding, side-dressing, or fertigting. With in-row fertiliztion, the N fertilizer ppliction rte is reduced proportionlly bsed on the frction of the field represented by the root zone. For exmple, if you wnt to pply 100 lb N/, but the root re (s determined by root pruning, hrvesting equipment, nd inter-row cultivtion) is equl to hlf of the totl field crege, you cn reduce the ppliction rte from 100 lb/ to 50 lb/ nd still get the expected tree growth response. Regrdless of ppliction method, N fertilizer pplied in dry form should be ccompnied with wter to move the fertilizer into the root zone nd prevent N loss to the tmosphere. Evluting N fertilizer mngement This publiction gives only generl guidnce for N mngement. You cn evlute the effectiveness of your N fertilizer progrm through trgeted testing in your own fields. For exmple: Try withholding N fertilizer from some plots; compre tree growth nd qulity to tht of trees treted with your norml fertiliztion progrm. Monitor soil nitrte-n in selected fields to refine N fertilizer rtes. Soil nitrte test interprettion depends on smpling loction (in-row or between rows) nd time of smpling (erly seson or lte seson). Smpling loction: Monitor soil nitrte in productive portions of the field, voiding grvel brs nd other typicl res. To get the best informtion, we suggest collecting seprte soil smples from between rows nd within rows. Nitrte-N smples tken within rows mesure N currently vilble to tree roots. Soil nitrte-n testing between rows is not recommended when N fertilizer is brodcst or if grss or cover crops re plnted between rows. When N fertilizer is pplied only in-row, soil nitrte-n smples tken from the unfertilized re between rows cn be used to estimte N contributed from non-fertilizer N sources, such s compost or cover crops. Time of smpling: In April June, soil nitrte tests cn be used to determine the need for dditionl midseson N fertilizer ppliction. In August September, test soil to determine whether the totl N supply (from irrigtion wter, soil, nd fertilizer) ws excessive. How to smple: Collect t lest 15 cores to depth of 1 foot using soil probe. Combine cores in sturdy plstic or plstic-lined bg, nd submit the composite smple to the lb for nlysis. Keep the smple cool nd ship to the lb vi next-dy delivery. If smple results re not needed immeditely, smples cn be frozen nd shipped lter. Phosphorus (P) Phosphorus (P) is immobile in the soil profile. Fertilizers such s superphosphtes, mmonium phosphtes, or other blended fertilizers re commonly top-dressed nd incorported between cropping cycles. Use Tble 1 to estimte P rte. Tble 1. Fertilizer phosphorus rte recommendtions using the Bry soil test. Soil test P Should you Apply this mount of P 2 O 5 (ppm) pply P? (lb/) Below 20 Yes 100 125 20 35 Mybe 60 100 Over 35 No None Bry soil test method. P, K, nd S djustment fter plnting If symptoms of P, K, or S deficiency re noted, these nutrients cn be pplied during the cropping cycle. Phosphorus deficiency results in stunting of growth, with drk green or possibly purpling of the folige. Chlorosis, then necrosis, occurs concurrently or follows in older leves. Potssium deficiency results in mrginl chlorosis, giving wy to rpid necrosis of the lef mrgin. Necrotic spots re sometimes visible on the entire lef. Sulfur deficiency results in uniform light green color or chlorosis over the entire plnt, followed by necrosis on lef tips. Phosphorus cn be pplied s liquid fertilizer such s 10-34-0 vi subsurfce fertigtion. Potssium nd sulfur cn be effectively supplied by brodcsting, top-dressing, or fertigtion. 3
Potssium (K) Potssium is usully top-dressed nd incorported between cropping cycles. Soil K is not used in gret quntities by trees nd does not decrese rpidly during cropping cycle. Use Tble 2 to determine K rte. Tble 2. Fertilizer potssium rte recommendtions using the mmonium cette soil test. Soil test K Should you Apply this mount of K 2 O (ppm) pply K? (lb/) Below 100 Yes 150 100 200 Mybe 0 150 Over 200 No None Ammonium cette soil test method. Potssium cn be pplied s potssium chloride (KCl), which lso provides the essentil element chloride (Cl). Chloride is believed to reduce shoot tip diebck nd increse crop wter sttus. Soil ph djustment Acidity, or ph, is the most commonly mesured chemicl chrcteristic of soil. Soil ph indictes the chemicl condition roots will experience. Soils in western Oregon re nturlly cidic (low ph); thus, for most crops, liming to rise soil ph is necessry. However, most shde tree species produced in the Willmette Vlley grow best in modertely cidic soil (ph 5.5 to 6.5). Some nursery crops, such s zles, rhododendrons, nd red mple (Figure 2), require more cidic soil (lower ph). For these species, reduction of soil ph (cidifiction) my be necessry. As shde tree producer, your gol is to mintin soil ph in the desired rnge throughout the crop production cycle (2 or 3 yers). Soil ph cn be reduced by ppliction of elementl sulfur (S) or incresed by dding lime. Soil ph djustments should be mde before plnting. One to 2 yers re required for elementl S or lime to fully rect with soil, lthough most of the rection tkes plce during the first yer. Even if mesured soil ph does not chnge immeditely, the prctice is benefit to trees during the first yer following ppliction. declines bout 0.1 unit/yer for ech 100 lb mmonicl N/. If you pply 100 lb N/ s ure ech yer, you should expect soil ph to decrese 0.3 unit in 3-yer tree production cycle. The type of N fertilizer used influences the rte of soil cidifiction. Fertilizers tht supply ll of the N in the mmonium (NH 4 ) form, such s mmonium sulfte (21-0-0), cidify soil the most. Ammonium sulfte is twice s cidifying s ure (46-0-0) nd ure-mmonium nitrte (Solution 32; 32-0-0) when the sme rte of N is pplied. Clcium mmonium nitrte (17-0-0) is less cidifying thn ure. Clcium nitrte (15.5-0-0) does not cidify soil. Rising soil ph Lime is used to rise soil ph (reduce cidity). The lime requirement test (SMP buffer test) estimtes the quntity of lime needed to increse soil ph, s shown in Tble 3 (pge 5). For exmple, if the SMP buffer test result is 6.2 (left column) nd the trget ph for your tree species is 6.4, the recommended lime rte (100-score limestone) is 3.2 t/. Note tht lthough Tble 3 provides guidelines, sesonl soil ph chnges nd vribility of soil in field mke the increse in soil ph from lime ppliction difficult to mesure. Two lime mterils re vilble in western Oregon clcitic (griculturl) lime nd dolomitic limestone. If soil test Mg is less thn 100 ppm (0.8 meq/100 g soil), use dolomitic lime for 1 t/ of the lime requirement. If the SMP buffer test for lime recommends more thn 1 t/, dd the remining lime s clcitic lime. Determining whether ph djustment is needed Lbortory determintion of soil ph will tell you whether ph djustment is needed. Collect soil smples for ph nlysis before plnting. Compre the current soil ph to your trget ph for the tree species nd cultivr grown. Keep in mind tht soil ph typiclly chnges by 0.3 to 0.5 unit sesonlly. It is lowest (most cidic) in lte August nd September, before the fll rins begin, nd highest in Februry or Mrch, when the soil is wettest. Soil ph lso decreses from use of mmonicl N fertilizer such s ure. Soil ph in the surfce 2 to 3 inches Figure 2. One-yer-old red mple trees. Oregon Stte University 4
Tble 3. Estimting lime requirement vi soil testing (SMP buffer test). Desired soil ph 5.3 5.6 6.0 6.4 Lime requirement SMP buffer vlue (t/) 6.7 or bove None None None None 6.4 None None 1.1 2.2 6.2 None 1.0 2.0 3.2 6.0 1.0 1.7 2.9 4.2 Amount of 100-score lime to pply per cre to rech the trget ph in the surfce 6 inches of soil. Reducing soil ph Elementl S is used to cidify soil (reduce ph). No soil test exists to determine S rte. The mount of S required to reduce soil ph is function of soil buffering cpcity (resistnce to ph chnge). The quntity of S needed to reduce soil ph increses with soil buffering cpcity. Willmette Vlley soils differ in buffering cpcity (Tble 4). Sndy, low orgnic mtter soils (e.g., Newberg) hve the lowest buffering cpcity. The highest buffering cpcity is found in soils with high cly nd orgnic mtter content (e.g., Bshw). Newberg soil (low buffering cpcity) requires bout hlf s much S s Bshw (high buffering cpcity) to chieve 1-unit chnge in ph. Clcium (C) nd mgnesium (Mg) Clcium soil test vlues bove 1,000 ppm (5 meq/100 g soil) re sufficient. Mgnesium is considered to be sufficient when soil test vlues re bove 100 ppm (0.8 meq/100 g soil). Soils with ph bove 5.5 typiclly hve sufficient C nd Mg. In the cse of lower ph soils, the lime tht is dded to rise ph lso stisfies the need for C nd Mg. Ech ton of 100-score lime (clcium crbonte) supplies pproximtely 2 meq C/100 g soil (400 ppm C) when incorported to 6-inch depth. One ton of dolomitic lime supplies pproximtely 1 meq Mg/100 g (120 ppm) nd 1 meq C/100 g (200 ppm). Only in rre circumstnces is C or Mg needed when the soil ph is bove 5.5 nd lime will not be pplied. In this cse, use the following guidelines: If soil test C is less thn 1,000 ppm (5 meq/100 g soil) or crops re symptomtic (distortion or chlorosis of new growth), 500 lb gypsum/ (clcium sulfte, CSO 4 ) cn be pplied to supply C. Clcium is lso supplied when N is pplied s clcium mmonium nitrte (27-0-0) or clcium nitrte (15.5-0-0). If soil test Mg is less thn 100 ppm (0.8 meq/100 g soil), pply 15 to 30 lb Mg/. When Mg nd soil cidifiction re needed, pply Mg s Sul-Po-Mg (potssium sulfte + mgnesium sulfte) or K-Mg (potssium sulfte). Do not pply dolomitic lime when soil cidifiction is needed. Tble 4. Acidifiction requirement for Willmette Vlley soils (0- to 6-inch depth) bsed on soil series. Elementl S required to reduce Soil buffering Typicl soil ph from 6.5 to 5.4 cpcity series (lb/) Low Newberg 1,100 1,500 Medium Chehlis Woodburn 1,600 2,000 Suvie Dyton Lurelwood Mlbon Powell Willkenzie High Jory Neki McBee 2,300 2,800 Very high Bshw Slem Amity 2,500 3,000 Adpted from Acidifying Soil for Crop Production (Western Oregon), OSU Extension publiction EM 8857-E. Sulfur (S) Sulfur cn be supplied by irrigtion wter, fertilizers, nd from decomposition of orgnic mtter. Soil tests provide little informtion on soil S sttus or vilbility. To ensure dequte S, pply t lest 20 lb S/ nnully. Common S sources include gypsum (CSO 4 ) nd fertilizers contining sulfte, such s mmonium sulfte [(NH 4 ) 2 SO 4 ] nd K-Mg. Sulfur cn be supplied during the cropping cycle s prt of liquid fertilizer or top-dress ppliction. (See the sidebr P, K, nd S djustment fter plnting, pge 3, for informtion bout S deficiency symptoms.) S moves into soil with irrigtion or rin. Note: Sulfte forms of S do not cidify soil. (See Reducing soil ph for informtion on soil cidifiction.) 5
Micronutrients Shde trees require few micronutrients, nd deficiencies of these elements re rre. When deficiency symptoms re observed, they likely re due to soil ph tht is too high for the species being grown. Micronutrients fll into three ctgories: Those tht merit no concern (copper nd molybdenum). These elements re not discussed below. Those tht re best hndled with soil ph modifiction (iron nd mngnese) Those tht cn be dded through fertiliztion (boron nd zinc). Mngnese (Mn) nd iron (Fe) Soil tests lone re not good indictors of deficiency of these micronutrients. Species grown, soil ph, nd soil dringe must lso be considered. Lef symptoms (Figure 3) re good indiction of need. Iron nd mngnese re very difficult to supply vi fertiliztion becuse soil ph controls vilbility to the plnt regrdless of nutrient pplictions to the soil. Cheltes ct s slow-relese source nd my be of some benefit. Folir pplictions my or my not be beneficil. Thus, the key to solving deficiencies of these nutrients is to reduce soil ph (see pge 5). Zinc (Zn) nd Boron (B) Zinc nd boron cn be dded to the soil for shde tree production if soil test vlues re below the threshold levels in Tble 5. Zinc pplictions should be bsed on soil test. When DTPA extrctble Zn flls below 1 ppm, pply Figure 3. Mngnese deficiency in red mple leves is chrcterized by interveinl chlorosis (in severe cses, necrosis). Source: Mnging Mngnese Deficiency in Nursery Production of Red Mple, EM 8905-E, Oregon Stte University. 5 to 10 lb Zn/. Zinc pplictions re needed t most once in rottion. Boron is esily leched out of soil with winter rins or irrigtion. Soil test B rrely exceeds the 1 ppm threshold given in Tble 5. However B is stored in the plnt, nd tissue levels usully re dequte (20 ppm) even when soil levels re low. Apply B once erly in rottion t rte of 0.5 to 1 lb/. Do not bnd B, s some species re sensitive to high soil B levels. Tble 5. Thresholds for micronutrient pplictions. Element Appliction threshold Boron 1.0 ppm Zinc 1.0 ppm Mngnese,b 1.5 ppm b Bsed on DTPA extrct. b For red mple, DTPA extrctble Mn is recommended to be bove 20 ppm nd ph below 5.6. Tble 6. Conversion fctors. To convert column 1 To convert column 2 into column 2, into column 1, divide by Column 1 Column 2 multiply by 390 ppm K meq K/100 g soil 390 200 ppm C meq C/100 g soil 200 121 ppm Mg meq Mg/100 g soil 121 1 meq/100 g soil cmol/kg soil 1 2 lb/cre (7-inch depth) ppm 2 3.5 lb/cre (1-foot depth) ppm 3.5 43.56 lb/cre lb/1,000 sq ft 43.56 43,560 squre feet cres 43,560 2.471 cres hectres 2.471 2.29 P P 2 O 5 0.437 1.20 K K 2 O 0.830 Conversion fctor given ssumes typicl soil bulk density (1.3 g/cm 3 or 80 lb/ft 3 ). 6
For more informtion Soil mps nd interprettions Nturl Resources Conservtion Service (NRCS) Web Soil Survey. http://websoilsurvey.nrcs.usd.gov/ OSU Extension publictions Soil Smpling for Home Grdens nd Smll Acreges, EC 628. http://extension.oregonstte.edu/ctlog/html/ ec/ec628/ Lbortories Serving Oregon: Soil, Wter, Plnt Tissue, nd Feed Anlysis, EM 8677. http://extension. oregonstte.edu/ctlog/html/em/em8677/ Acidifying Soil for Crop Production West of the Cscde Mountins, EM 8857-E. http://extension.oregonstte. edu/ctlog/pdf/em/em8857-e.pdf Mnging Mngnese Deficiency in Nursery Production of Red Mple, EM 8905-E. http://extension. oregonstte.edu/ctlog/html/em/em8905-e/ Fertilizer nd Liming Mterils Guide, FG 52-E. http://extension.oregonstte.edu/ctlog/html/fg/ fg52-e/ Acknowledgments Thnk you to the following for their ssistnce with this publiction: Hether Stoven, fculty reserch ssistnt, North Willmette Reserch nd Extension Center, Oregon Stte University; Lnce Lyon, consultnt, Lnce Lyon Consulting; Ross Dumdi, West Cost plnt helth deprtment hed, Biley Nurseries, Inc.; nd Sm Done, production horticulturist, J. Frnk Schmidt nd Son Co. 2010 Oregon Stte University. This publiction my be photocopied or reprinted in its entirety for noncommercil purposes. This publiction ws produced nd distributed in furthernce of the Acts of Congress of My 8 nd June 30, 1914. Extension work is coopertive progrm of Oregon Stte University, the U.S. Deprtment of Agriculture, nd Oregon counties. Oregon Stte University Extension Service offers eductionl progrms, ctivities, nd mterils without discrimintion bsed on ge, color, disbility, gender identity or expression, mritl sttus, ntionl origin, rce, religion, sex, sexul orienttion, or vetern s sttus. Oregon Stte University Extension Service is n Equl Opportunity Employer. Published October 2010.