Establishing Peach Trees for Organic Production in Utah and the Intermountain West

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1 Uth Stte University Plnts, Soils, nd Climte Fculty Pulictions Plnts, Soils, nd Climte Estlishing Pech Trees for Orgnic Production in Uth nd the Intermountin West Jennifer R. Reeve Uth Stte University C. M. Culumer University of Cliforni Coopertive Extension Brent Blck Uth Stte University Andrew Teeu Uth Stte University Corey Rnsom Uth Stte University Dine Alston Uth Stte University See next pge for dditionl uthors Follow this nd dditionl works t: Prt of the Plnt Sciences Commons Recommended Cittion Reeve, Jennifer R.; Culumer, C. M.; Blck, Brent; Teeu, Andrew; Rnsom, Corey; Alston, Dine; Rowley, M.; nd Lindstrom, Thor, "Estlishing Pech Trees for Orgnic Production in Uth nd the Intermountin West" (2017). Plnts, Soils, nd Climte Fculty Pulictions. Pper This Article is rought to you for free nd open ccess y the Plnts, Soils, nd Climte t DigitlCommons@USU. It hs een ccepted for inclusion in Plnts, Soils, nd Climte Fculty Pulictions y n uthorized dministrtor of DigitlCommons@USU. For more informtion, plese contct dyln.urns@usu.edu.

2 Authors Jennifer R. Reeve, C. M. Culumer, Brent Blck, Andrew Teeu, Corey Rnsom, Dine Alston, M. Rowley, nd Thor Lindstrom This rticle is ville t DigitlCommons@USU:

3 1 2 Estlishing pech trees for orgnic production in Uth nd the Intermountin West J.R. Reeve 1, C.M. Culumer 2, B.L. Blck 1, A.Teeu 3, C.V. Rnsom 1, D. Alston 3, M. Rowley 1, T. Lindstrom Deprtment of Plnts, Soils nd Climte, Uth Stte University, Logn, UT University of Cliforni Coopertive Extension, Fresno County, 550 E. Shw Avenue, Suite 210-B Fresno, CA Deprtment of Biology, Uth Stte University, Logn, UT Additionl key words. Orgnic stone-fruit estlishment, tree growth, soil fertility Astrct. Adequte weed control nd nutrient supply re criticl for successful estlishment of fruit trees. This is of prticulr concern in orgnic orchrd estlishment. In order to determine the est pproch for estlishing pech trees (Prunus persic L.) orgniclly in climtes chrcterized y hot dry summers nd cold winters such s the North Americn Intermountin West, seven orgnic nd three integrted nd conventionl tretment comintions were estlished in two first lef orchrds t the USU Kysville Reserch Frm, Uth, in 2008 nd Tretments consisted of different tree-row nd lleywy mulch nd fertilizer comintions. Compost or conventionl fertilizer ( nd ure) were pplied t seline rte of 4.9, 9.6, 1

4 g nd 114 g of ville nitrogen (N) per 1 st, 2 nd, 3 rd nd 4 th lef tree respectively nd djusted up or down on plot sis sed on tree growth. Compost ws supplemented with fether mel fertilizer strting in yer three to void over ppliction of phosphorus (P) nd potssium (K). Orgnic experiment tree growth ws initilly slowed y living nd strw mulches present in the tree-row. By 2011, 3 rd lef trees were lrgest in tretments with Birdsfoot trefoil lleywys, despite considerle tree-row weed/living mulch pressure. In the integrted experiment, trees were lrger in the compost plus conventionl hericide compred to conventionl fertilizer nd hericide tretment. Pper mulch depressed tree growth in comintion with oth compost nd conventionl N sources, ut more so in comintion with compost nd orgnic hericide where weed control ws moderte. Weed pressure not lck of N ws determined to limit orgnic tree growth in this study. A trefoil lleywy my llevite the need for intensive weed control when estlishing orgnic pech orchrds Introduction The United Sttes (US) mrket for orgnic produce continues to grow despite the recent economic downturn (Dimitri nd Oerholtzer, 2009; Slttery et l., 2011). Growth in tree fruits nd erries hs een prticulrly strong with orgnic pech production incresing y 116 percent etween 2008 nd 2011 (Perez nd Plttner, 2013). Orgnic production in the US hs lrgely filed to keep pce, nd meeting consumer demnd continues to e chllenge (Dimitri nd Oerholtzer, 2009). Uth nd the Intermountin Western US re trditionl producers of high qulity tree fruit with high elevtions, wrm dytime tempertures nd cool nights during the summer, resulting in fruit tht is exceptionlly sweet nd flvorful. Overll fruit production hs 2

5 dwindled in recent yers due to urniztion nd chnging mrkets, lthough the plnted re of trt cherries nd peches hs remined stle (Ernst et l., 2012; Uth Fruit nd Berry Survey, 2006). The rid climte of the Intermountin West with reltively low disese pressure confers considerle dvntges for orgnic production nd growing urn centers provide ccess to mrkets. Currently, certified orgnic tree fruit in Uth is limited to few very smll producers, however. Chllenges include lck of locl expertise, short growing sesons with cold winters nd shllow lkline soils low in orgnic mtter. Strengthening n orgnic tree fruit industry in the region will require loclly dpted est mngement strtegies, something tht is currently lcking A mjor chllenge to estlishing new orgnic orchrds is the trnsition process. Successful orgnic production requires growers mnge soil reserves of redily ville nutrients s most orgnic fertilizers minerlize slowly in the short-term. Building sufficient soil nutrient reserves cn tke time, especilly in soils with very low ntive orgnic mtter nd high ph. Young fruit trees re prticulrly susceptile to competition from weeds which compete for wter nd nutrients nd often provide refuge for pests (Skroch nd Shris, 1986; Hoglnd et l., 2008, Tworkoski nd Glenn, 2008). Bre soil or mintennce of n hericide or tillge strip is generlly preferred during the orchrd estlishment phse in oth orgnic nd conventionl production (Welker nd Glenn, 1991; Lyne et l., 1994; Neilsen nd Hogue, 2000; Tworkoski nd Glenn, 2008). Tillge long with pplictions of compost is commonly used orgnic orchrd floor mngement system in the US (Hoglnd et l., 2008). Adequte quntities of high qulity compost cn e difficult nd expensive to otin, however, while frequent tillge hs 3

6 69 70 een shown to disrupt surfce roots nd tree stility, nd reduce soil qulity over the long term (Skroch nd Shris, 1986; Hoglnd et l., 2008) An lterntive or complement to compost nd other expensive orgnic inputs is to grow legumes in the orchrd (Grntstein nd Sánchez, 2009; Rowley et l., 2011). Legumes re cple of supplying significnt N to fruit trees. Suterrnen clover is used in costl orchrd regions in the US ecuse of its low growth hit. In Cliforni study, suterrnen clover grown in the tree-row ws found s effective s high 90 kg N h -1 pplictions of compost + ntive vegettion for estlishment of young pech trees t only frction of the cost of compost (Meyer et l., 2006). Mny growers in Colordo nd Uth plnt orchrds into estlished lflf nd mnge weeds y mowing. However, this prctice hs not een formlly evluted nd hs generlly een discourged in pech orchrds due to the potentil for prolems with pests, prticulrly ct-fcing insects (Killin nd Meyer, 1984) Legumes cn lso strongly inhiit tree growth through competition (Skroch nd Shris, 1986; Hoglnd et l., 2008; TerAvest et l., 2011). An Itlin study showed tht suterrnen clover inhiited erly growth of pech trees compred to tillge control (Antonelli et l., 1997). Merwin nd Stiles (1994) showed similr competition prolem with crown vetch plnted in the tree- row of estlishing pple trees. In trt cherry, Sánchez et l. (2003) showed tht legumes incorported into tree-row cover crop mixes did not increse yield reltive to mixes with fewer or no legumes. Although fertigtion + living mulches reduced yield discrepncies in this Michign study. Stsik nd Rom (1991) indicted tht competition effects my e short lived in estlishing pech orchrds, however. In ddition, locting the legumes in the lleywy versus 4

7 92 93 the tree-row my e criticl to reducing competition nd optimizing enefits (Grntstein nd Sánchez, 2009; Mullinix nd Grntstein, 2011) There is lso considerle interest in mulch, mde from vrious orgnic nd inorgnic mterils, for weed control in orgnic orchrds (Grntstein nd Mullinix, 2008; Tworkoski nd Glenn, 2008: Cline et l., 2011; TerAvest et l., 2011). Hoglnd et l. (2008) demonstrted good weed control with wood chip mulch, lthough tree nutritionl prolems were oserved nd soil qulity ws somewht impired. Use of woven fric mulch ws used successfully in sweet cherry estlishment (Nunez-Elise et l., 2005) lthough Neilsen nd Hogue (1992) showed drmtic reductions in soil nd lef K in pple. Yield ws highest in trt cherry systems receiving supplementl grss legume mulch comined with glyphoste s needed (Snchez, 2003). And pper mulch significntly incresed growth of pple (Hogue et l., 2010). Strw is effective for weed control during rsperry estlishment (Bushwy et l., 2008) nd my sufficiently cool soil tempertures in the erly spring to prevent premture ud rek (Wlsh et l. 1996; Wng et l. 2015), n incresing prolem in chnging climte. Mulches my lso hold dditionl enefits in terms of conserving soil moisture (Wlsh et l. 1996; Wng et l. 2015). Incresed rodent ctivity is of potentil concern, however (Sullivn et l. 1998) The gol of this study ws to evlute orchrd floor mngement prctices for estlishing orgnic pech trees in environments chrcterized y hot dry summers, cold winters nd shllow lkline soils such s the Intermountin Western US. Two orchrds were estlished in 2008 t the USU Kysville Reserch Frm, Uth. A certified orgnic orchrd ws plnted to test the effects of living nd strw mulches s weed mngement strtegies in the tree-row in 5

8 comintion with grss or legumes grown in the lleywy. These tretments were compred to common orgnic methods of mintining weed free tree-rows, tillge nd fric mulch, with grss lleywys. A second orchrd ws estlished to investigte the interction etween nutrient vilility from orgnic fertilizers nd weed competition Mterils nd Methods Site history, experimentl design nd mngement. Two pech orchrds (Prunus persic L.) were estlished in neighoring fields t the USU Horticulture Reserch Sttion in Kysville, UT (41 1'16.73"N, '43.37"W, 1336 m elevtion). The fields were fllow prior to 2005 nd were then plnted to succession of summer nd winter cover crops to fcilitte weed control. The soil type ws Kidmn fine sndy lom. In April 2008, the two sites were cler cultivted nd the orchrds plnted. The orgnic experiment ws plnted in twelve rows of 30 trees with 2.44 m in-row nd 4.88 m etween-row spcing, in rndomized complete lock design with four locks. The integrted experiment ws plnted in twelve rows of 25 trees with the sme spcing nd design descried ove. The locking fctor represented cultivr ( Strfire nd Corlstr on Lovell rootstock) nd loction within ech orchrd. Cultivrs were plnted in lternting locks of three rows ech resulting in plots of 3 x 5 trees in size with six (orgnic) or five (integrted) tretments per lock. The three centrl trees in ech 15 tree plot were designted s dt trees; the surrounding trees served s gurd trees to protect the dt trees from edge effects. This lyout resulted in two gurd rows etween dt rows nd two gurd trees etween dt trees in row

9 Tretments were estlished in ech experimentl orchrd in June of Orgnic experiment: strw mulch with grss lleywy (StGr), strw mulch nd Birdsfoot trefoil (Lotus cornicultus) lleywy (StTr), living mulch (low-growing shllow rooted llysum, Loulri mritim) with grss lleywy (LmGr), living mulch nd legume lleywy (LmTr), woven plstic mulch (5oz. Dewitt, Sikeston, MI) with grss lleywy (WfGr) nd tillge with grss lleywy (TiGr). Tretments ssigned to the integrted experiment were: conventionl fertilizer plus hericide (CfH), compost s orgnic fertilizer plus hericide (OfH), conventionl fertilizer with pper mulch nd reduced hericide (CfM) nd compost with pper mulch nd orgnic hericide (OfM). All lleywys in the integrted experiment were plnted to grss. Tretments StGr, StTr, LmGr, nd LmTr were mnged ccording to the sndwich system (Hoglnd et l., 2008) with nrrow 0.3 m tilled strip mintined etween the tree-row nd lleywy using trctor mounted rototiller. In the orgnic experiment significnt numer of dt trees filed to grow ove the grft during the first seson so ll dt-row trees were replnted in April Chicken mnure compost ws pplied to ll tretments in the orgnic experiment nd tretment OfH nd OfM in the integrted experiment in 2008, nd compost mde of steer mnure, steer stomch contents upon slughter nd wood chips ws pplied in Compost ws pplied round the drip line of the tree within the tree-row in tillge, weed fric, hericide nd pper mulch tretments, nd to the tillge strips in the strw nd living mulch tretments. Compost hd totl N content of 1.89, 1.46, 2.25, nd 2.10 % nd C:N rtio of 7:1, 13:1, 12:1 nd 10.9 in respectively (Tle 1). Appliction rtes in the orgnic experiment were clculted to supply 17, 24, 32 nd 51 g totl N from 2008 to 2011 respectively, 7

10 ssuming ville N of 20 % in 2008 nd 2009, 30 % in 2010 nd 25 % in Appliction rtes in the integrted orchrd were higher (17, 48, 63 nd 51g N from 2008 to 2011 respectively) due to the fct tht the trees were one yer older. Individul compost rtes were djusted up or down on plot sis reltive to the se rte sed on tree growth (Tle 2). Due to rpidly rising soil P, the seline rte of compost ws limited to 2.26 kg per tree in 2011 nd the dditionl N provided through the ppliction of n orgniclly pproved fether mel product (NtureSfe , Irving, TX) in lte My. Conventionlly fertilized trees (CfH nd CfM) received 4.8, 9.6, 19.2g nd 19.2g N in the form of , from nd n extr 95 g N in the form of ure (46-0-0) in Elementl sulfur (S) ws pplied to the soil t rte of 90 g per tree in erly Decemer 2010 due to low soil nd lef test S vlues. Tissue tests lso reveled trce element deficiencies so folir pplictions of trce elements were pplied eqully to ll tretments s needed strting in An orgnic pproved pest mngement progrm for the control for pech twig orer, greter pech tree orer (pheromone-sed mting disruption nd microil insecticide) nd coryneum light (copper) ws instigted cross oth orchrds in Horticulturl oil for pech phid control ws pplied in 2010 nd Fresh strw ws dded t rte of ~4 kg per tree to the strw tretments (StGr nd StTr) in Mrch 2008 nd This rte ws reduced to 2 kg per tree in 2010 nd The strw pplied ws either whet (Triticum estivum) or rley (Hordeum vulgre). Spry-on pper mulch (Nture s Own orgnic hydro-seeding mulch, Hmilton Mnufcturing Inc. Twin Flls, ID) ws mixed with wter nd pplied with hydro-seeder to tretments CfM nd OfM in Mrch. The fric mulch (WfGr) ws rolled ck ech fll to prevent rodent dmge to tree trunks nd replced ech Mrch fter fertilizers were pplied. The lyssum plnted in the living 8

11 mulch plots (LmGr nd LmTr) filed to re-estlish following the winter of 2008, most proly due to lte frost tht killed the emerging seedlings. It ws reseeded in 2009 nd 2010, however, stnds in those yers were poor due to incresing perennil weed pressure, nd in 2011 the living mulch tretment ws llowed to generte spontneously from weeds lredy present. The lleywys were mowed pproximtely monthly nd in the trefoil tretments (StTr nd LmTr) the clippings were lown into the tree-row nd llowed to remin on the surfce. Living mulches nd weeds in tree-rows were mowed s needed pproximtely monthly. The tillge tretment (TiGr) ws mintined y hnd using stirrup hoe pproximtely once per month. Glyphoste hericide ws pplied twice per yer to the conventionl nd compost hericide tretments (CfH nd OfH) nd once per yer to the pper mulch tretment (CfM) t rte of 1.5% in spry volumes of 234 to 281 L h -1. A single ppliction of clove oil orgnic hericide (Mtrn, Ecosmrt Technologies Inc, Ames, IA) ws pplied to the orgnic tretment with pper mulch (OfM) ccording to lel recommendtions in 2009 nd Acetic cid (Weed Phrm) ws pplied to this tretment two times t rte of 280 L h -1 in Ech plot ws irrigted independently using micro sprinklers. We previously found tht orchrd wter use differed y the species of orchrd floor vegettion (Rowley et l. 2011). For this study, irrigtion needs were determined for ech plot. Irrigtion volumes to e pplied were clculted sed on soil volumetric wter content, mesured ech week per plot prior to irrigtion, using cpcitnce proe (Diviner 2000, Sentek Technologies, Stepney, Austrli). Hence soil moisture ws returned to field cpcity ech week to reflect ctul wter use y tretment Tree growth, nutrition nd soil fertility. 9

12 Trunk cross sectionl re ws clculted ech winter using trunk dimeters mesured with forestry tpe mesure 30 cm ove ground level, nd cnopy dimeter, shoot elongtion nd pruning weights determined ech spring. Tree nutritionl sttus ws determined y nlyzing rndom smple of the 3 rd fully expnded leves in lte July or erly August. Lef smples were rinsed in ddh2o nd dried t 70 C for 72 hours, ground to < 0.2µm with UDY mill (UDY corp, Fort Collings, CO). The lef smples were nlyzed for totl N, P, K, C, Mg nd trce elements t the USU Anlyticl L (Logn, UT) in 2010 nd Alion Lortories (Clerfield, UT) in Soil nitrte (NO3 - ) nd mmonium (NH4 + ) were determined during the growing seson t monthly intervls from My through August. Six rndom soil smples per plot were collected from the tree-row (0-30 cm) with 1.6 cm proe, comined, pssed through 2-mm sieve, extrcted immeditely in 1M KCl nd mesured on QuickChem Lcht (Ltcht Instruments, Lovelnd, CO) using the sulfnilmide nd phente methods ccording to mnufcturer s instructions. Soil ph, electricl conductivity (EC) nd mcro nd micro elements were mesured yerly on ir-dried soils in June ccording to Gvlk et l. (2003). Orgnic cron (C) nd nitrogen (N) were mesured y dry comustion with PrimcsSNC totl C nd N nlyzers (Sklr, Inc, Buford, GA) on finely ground (<0.2 µm) soil smples collected s ove from 0-10 cm depth. Inorgnic C ws found present in trce quntities only in the top 10 cm so totl C ws ssumed to equl orgnic C. 2.3 Sttisticl nlyses. Tree growth, nutrient sttus nd soil fertility in response to tretment were nlyzed using n incomplete rndomized lock design with two fctors in PROC GLIMMIX in the SAS System 10

13 for Windows (SAS Institute, Cry, NC). In the orgnic experiment, the fctors were lleywy nd tree-row with time s repeted mesures. Min effects were compred to weed-free control tretments using contrst sttements. In the integrted experiment, the two fctors were fertilizer type nd method of weed control. When significnt tree-row x lleywy interction ws detected ll tretments within ech experiment were nlyzed s one-wy design with repeted mesures. In ll cses experimentl fctors nd time were modelled s fixed effects while lock ws modelled s rndom effect Results nd Discussion Tree Growth. Weed fric nd tillge tretments initilly incresed tree trunk cross sectionl re reltive to the living mulch tretments in the orgnic orchrd (Figure 1). However, y 2011 trees grown with trefoil lleywys (LmTr nd StTr) were s lrge s the weed free control tretments (TiGr nd WfTr) while trees grown with grss lleywys (LmGr nd StTr) were significntly smller. This suggests tht trees grown with trefoil in the lleywy were le to ccess more resources (nutrients nd wter) thn trees grown with grss lleywy despite considerle weed pressure in the tree-row (Tle 3). In ddition to N supplied y the compost nd fether mel, trefoil iomss lown into the tree-row generted n dditionl 0.1 kg / tree or 73 kg totl N h -1 (Tle 2). This more thn douled the totl N pplied to the trefoil tretments per yer which could possily ccount for the dditionl tree growth. However, the mount of this surfce deposited N ville for tree uptke is uncler (Ferreir et l., 2015). And incresed tree growth could lso e ssocited with incresed tree root growth nd improved ccess to soil resources (Prker nd Myer, 1996). Strw mulch helped to suppress weeds, nd this ws reflected in modest increse 11

14 in tree trunk cross sectionl re (Figure 1, Tle 3), overll however, tree growth ws dominted y legume lleywy effects Trils in New Zelnd, Uth nd Portugl showed orchrd-grown legumes hve the potentil to generte kg totl N h -1 (Goh et l., 1995; Rowley et l., 2011; Ferreir et l., 2015). Legumes hve lso een shown to strongly inhiit tree growth through competition, however (Skroch nd Shris, 1986; Merwin nd Stiles, 1994; Antonelli et l., 1997; Hoglnd et l., 2008; TerAvest et l., 2011). Effects of ground cover competition is known to e species specific, with lflf less competitive with pech thn mny grsses (Prker et l., 1993; Prker nd Meyer, 1996). The resons re uncler, ut could relte to root morphology, specificlly the tp-rooted structure of lflf nd other legumes such s Birdsfoot trefoil. Blck et l., (2010) showed tht root growth of trt cherry in orchrds mnged with grss lleywy ws primrily constrined to the re elow the hericide strip, confirming the need for weed control in orchrds mnged with grss lleywys. Locting legumes in the lleywy versus the tree-row, s in this study, my e criticl to reducing competition in the lleywy, hence optimizing the enefits of orchrd-grown legumes nd reducing tree susceptiility to weed pressure (Grntstein nd Sánchez, 2009; Mullinix nd Grntstein, 2011) In the integrted experiment, there were initilly few differences etween tretments in tree trunk cross sectionl re (Figure 2). By 2011, however, tree trunk cross sectionl re in the OfM tretment ws lowest. No difference in trunk cross sectionl re etween the OfH tretment nd the conventionl tretment suggests tht reduced tree growth in the OfM tretment ws cused y indequte weed control rther thn lck of N (Tle 4). There were no 12

15 differences etween the CfM tretment nd the conventionl control indicting tht pper mulch ws not immoilizing N, t lest with conventionl fertilizer. Conventionl trees in the integrted experiment trnsitioned to orgnic mngement eginning in 2011, quickly ecme chlorotic nd stunted compred to other conventionlly mnged trees (dt not shown). This illustrtes the chllenges ssocited with trnsitioning mture trees to orgnic production on soils tht re nturlly low in orgnic mtter with poor nutrient reserves Soil Properties. Soil properties in the tree-row responded positively to compost dditions, cover crops, nd orgnic mulches in oth experiments. Similr results hve een demonstrted in response to orchrd ground cover nd mulch in rnge of climtes nd soil types (Snchez et l., 2003; Hoglnd et l., 2008; Tworkoski nd Glenn, 2008; Rmos et l., 2011; TerAvest et l., 2011). In the orgnic experiment in Uth, totl orgnic soil C significntly incresed in the top 10 cm in the trefoil tretment two yers fter estlishment, while incresed totl orgnic N ws seen in response to trefoil y the third yer (Figure 3 nd 4). Weed fric lso ppered to improve soil C ut only in one yer out of four. While oth strw nd living mulch incresed soil C nd N compred to tillge nd weed fric, there were no differences etween strw nd living mulch. Compost consistently incresed soil totl C nd N compred to conventionl fertilizer eginning from orchrd estlishment (Figure 5). Significnt effects of pper mulch on totl C were not pprent until yer three, however, with no differences mesured in totl N (dt not shown) Aville N (NO3 - nd NH4 + ) in the tree-row vried considerly etween tretments nd yer, lthough trefoil incresed soil NO3 - in three out of four yers (dt not shown). These 13

16 findings re in contrst to Ferreir et l. (2015), who found no increse in soil N s result of surfce deposited legume residue. Compost incresed soil NO3 - reltive to conventionl fertilizer in 2009 with the opposite effect in In generl soil NO3 - levels were low (elow 15 mg kg -1 ) suggesting tight coupling etween N minerliztion nd tree uptke in the tree-row. Nutrient sttus in the lleywy ws not mesured in this study Aville soil P nd K incresed drmticlly (2-3x seline levels) within one yer of compost ppliction (Figures 6 nd 7) well ove the recommended levels of nd mg kg -1 for P nd K respectively (Crdon et l., 2008). For this reson, compost rtes were reduced in 2011 with supplementl N supplied through dditions of fether mel. Elevted soil P is ssocited with inhiition of trce element uptke s well s surfce wter eutrophiction (Mrschner, 1995; Allowy, 2009). Elevted soil K cn compete with C nd Mg uptke nd reduce fruit qulity, prticulrly in pple (Mrschner, 1995; Mercelle, 1995). This reflects the chllenge of relying on compost lone for soil fertility, even if dequte quntities re cheply ville. Once compost pplictions were reduced to meet projected orchrd P s opposed to N needs, soil ville P nd K returned to more cceptle levels. Alleywy tretment effects on soil P were non-significnt, nd tree-row effects highly vrile y yer, lthough there ws tendency for strw mulch to increse soil ville P. Both strw nd trefoil hd tendency to increse soil ville K, lthough gin, yer to yer vriility ws high thus mking interprettion difficult Other soil mcro nd micro elements were highly vrile y yer with few cler tretment ptterns emerging. Living mulch incresed soil C nd Mg reltive to strw mulch in 14

17 two out of four yers while trefoil incresed ville soil Mn. In the integrted experiment, compost incresed soil C, Mg, N, nd S in 2009 nd 2010, nd Cu nd Zn in When compost rtes were reduced in 2011, differences lrgely disppered, however (dt not shown). Soil ph t this site remined t 8.0 throughout with no tretment effects noted in ny of the tretments in either orchrd Tree lef nutrients. Tree lef nutrients lso vried chiefly y yer s opposed to tretment. In the orgnic experiment there were no tretment effects on tree lef N. Legumes hve een ssocited with excessive lte seson N uptke which cn contriute to winter ud kill nd fruit qulity prolems (Tworkoski nd Glenn, 2008). This ws not oserved in our study, perhps ecuse of low ntive soil orgnic mtter. Growers in Uth frequently pply N in the fll to increse tree growth in the spring due to low ntive soil reserves. Lef P ws significntly greter in grss nd weed fric tretments compred to trefoil, with tillge intermedite. Trefoil tretments hd greter lef K thn grss nd weed fric in 2010 nd greter lef K thn tillge nd weed fric in In the integrted experiment, pper much reduced tree lef N in 2009, lthough not to deficiency levels, nd conventionl fertilizer incresed tree lef N over compost in Compost incresed tree lef P in ll yers, K in 2009 nd 2010 nd Zn in Pper mulch incresed tree lef P in 2011 ut there were no other tretment effects on tree lef nutrients (dt not shown). The tendency for oth compost nd mulch to increse lef K ws lso documented y Mrsh et l. (1996) in orgnic pple. Although Toselli et l. (2012) nd de Melo et l. (2016) found no effect of compost on the nutrient content of pech leves despite incresed yields

18 Lef tissue S, C, nd Mn frequently tested low in ll tretments in this study (Mills nd Jones, 1996) nd so ll trees were mended with folir pplictions of C nd trce elements. Low lef tissue S ws resolved fter soil pplictions of S in In 2010 nd 2011, lef tissue P tested ove norml, lthough this fell ck to within norml levels fter compost ws reduced (dt not shown). Low lef tissue C is ttriuted to competition with K s well s dry nd sndy soil conditions, ll of which were present t this site. Low lef tissue Mn cn e explined y low soil vilility t high soil ph. Trefoil incresed the vilility of soil Mn in this study nd compost incresed the vilility of soil Zn in 2011, lthough this ws not reflected in incresed tree lef Mn or Zn. Hshemimjd nd Jmti-e-Somrin (2011) showed use of compost incresed the vilility nd tree lef sttus of Zn nd Fe in pech grown on clcreous soil. And Sorrenti et l. (2012) showed similr findings in per. Peck et l. (2006) found orgnic pple grown on clcreous soil deficient in Zn, however. Further monitoring is needed to determine whether long-term chnges in soil nutrient vilility trnsltes into improved pech tree nutritionl sttus in clcreous soils. This study design ws unusul in tht ech tretment ws treted s discrete system with respect to N nd wter inputs. The gol ws to mnge ech system optimlly y decresing fertilizer N inputs in tretments receiving legume N inputs nd incresing N inputs when tree growth ws reduced (Tle 2). Similrly, irrigtion ws trgeted sed on soil wter drwdown in ech plot, ensuring wter ws pplied optimlly to ech tretment. In spite of tretment specific N nd wter mngement, we were unle to overcome the negtive effects of weed competition in tretments with grss lleywy. Despite reduced externl N inputs, trees with trefoil lleywy were lrgest even with significnt living mulch/weed pressure in the tree-row. 16

19 Reserch is ongoing to determine the extent to which externl N sources cn e reduced further in tretments with trefoil lleywy Conclusions Improved methods for trnsition to orgnic production re needed to ssist growers in meeting the incresing demnd for orgnic fruit. Trunk cross sectionl re of newly plnted pech trees ws initilly reduced when estlished with living mulch s opposed to ctive weed mngement in the tree-row. By the third lef, however, trees plnted with trefoil lleywys were significntly lrger thn trees plnted with grss lleywys, with no difference etween trees mnged with tillge or weed fric. Trunk cross sectionl re in trees grown with legume lleywys ws lso equivlent to trees of similr ge mnged conventionlly. This suggests tht trees with trefoil lleywys were le to ccess more resources thn trees with grss lleywys, despite considerle weed pressure in the tree-row nd reduced externl inputs. Conversely, trees estlished with grss lleywys were shown to e highly dependent on weed mngement in the tree-row, with no difference found etween trees mnged with orgnic fertilizers nd hericide nd those mnged conventionlly. Totl tree growth s indexed y trunk cross sectionl re ws reduced sustntilly when pper mulch with orgnic vs. conventionl hericide ws used, llowing for the uildup of weeds over time. Incresed N inputs did not overcome this competition effect. Surfce deposited legume mulch nd compost positively ffected soil C nd N sttus. Compost when used lone to meet tree N needs, incresed soil P nd K levels to uncceptle levels which necessitted the replcement of some compost pplied N with fether mel. Greter tree growth in legume tretments my e ssocited with greter soil N lthough the potentil for reduced tree root competition with trefoil vs. grss in the lleywys deserves 17

20 further study. More reserch is lso needed to replicte these results in rnge of soil types nd climtes. In the mentime, these findings strongly suggest tht growing legumes such s Birdsfoot trefoil in the lleywys could e successful pproch to estlishing orgnic pech orchrds with the potentil to significntly improve soil helth nd reduce costs ssocited with intensive weed control nd expensive externl inputs Acknowledgements This reserch ws supported y the USDA NIFA Orgnic Reserch nd Eduction Inititive (OREI), the Uth Deprtment of Agriculture nd Food Specilty Crop Block Grnt Progrm (UDAF SCBG), the Uth Agriculturl Experiment Sttion (UAES) nd the Uth Stte Coopertive Extension Service. Mny thnks to Susn Durhm for ssistnce with sttisticl nlysis nd to Alici Cmpell, Gi Nfziger nd Lenn Hyes for technicl ssistnce in the field nd lortory. This rticle ws pproved s UAES journl pper # Literture Cited Antonelli, M.A. Chiriotti, M.R. Tilio, M. Ronco, nd P. Di Prospero Effects of different mngement techniques utilized in n orgnic pech orchrd during the trining phse. Act Hort (ISHS). 465: Allowy, B.J Soil fctors ssocited with zinc deficiency in crops nd humns. Environ. Geochem. Helth. 31:

21 Blck, B.L. D.T. Drost, T. Lindstrom, J.R. Reeve, nd G.L. Reighrd A comprison of root distriution ptterns mong Prunus rootstocks. Journl of the Americn Pomologicl Society 64: Bushwy, L. M.P. Pritts, nd D. Hndley Rsperry nd Blckerry Production Guide: For the Northest, Midwest, nd Estern Cnd. Nturl Resource Agriculture, nd Engineering Service Coopertive Extension, Puliction # Crdon, G.E. J. Kotuy-Amcher, P. Hole, nd R. Koenig Understnding your soil test report. Uth Stte University Coopertive Extension puliction AG/Soils/ pr Cline, J. G., Neilsen, E. Hogue, S. Kucht, nd D. Neilsen Spry-on-mulch technology for intensively grown nd irrigted pple orchrds: influence on tree estlishment, erly yields, nd soil physicl properties. HortTechnology 21: De Melo, G.W.B., Sete, P.B. Amrosini, V.G. Freits, R.F. Bsso, nd A. Brunetto, G Nutritionl sttus, yield nd composition of pech fruit sujected to the ppliction of orgnic compost. Act Scientirum-Agronomy. 38: Dimitri C. nd L. Oerholzter Mrketing US Orgnic Foods. Recent Trends from Frms to Consumers. USDA Economic Reserch Service. Economic Informtion Bulletin Numer

22 Ernst, T., S.D. Rowley, B.L. Blck nd T.R. Roper Reviewing potentil locl fruit mrkets: A Uth cse study. Journl of the Americn Pomologicl Society 66: Ferreir I.Q., M. Angelo Rodrigues, A.M. Clro, nd M. Arros Mngement of nitrogen-rich legume cover crops s mulch in trditionl olive orchrds. Communictions in Soil Science nd Plnt Anlysis. 46: Gvlk R., D. Horneck, R.O. Miller, nd J. Kotuy-Amcher Soil, Plnt nd Wter Reference Methods for the Western Region, 2 nd edn. WCC-103 Puliction, Colordo Stte University, Ft. Collins, Colordo, USA Goh, K.M., G.E. Ridgen, nd M.J. Dly Understory iomss production nd iologicl nitrogen fixtion in n orgnic pple orchrd in Cnterury, New Zelnd. Communictions in Soil Science nd Plnt Anlysis. 26: Gomez-Munoz, B., D.J. Htch, R. Bol, nd R. Grci-Ruiz Nutrient dynmics during decomposition of the residues from sown legume or ruderl plnt cover in n olive oil orchrd. Agriculture Ecosystems nd Environment. 184: Grntstein, D. nd K. Mullinix Mulching options for Northwest orgnic nd conventionl orchrds. HortScience, 43: Grntstein, D. nd E. Sánchez Reserch knowledge nd needs for orchrd floor mngement in orgnic tree fruit systems. Interntionl Journl of Fruit Science 9:

23 Hshemimjd, K nd Jmti-e-Somrin, S Investigting the effect of iron nd zinc enriched vermicompost on growth nd nutritionl sttus of pech trees. Scientific Reserch nd Essys. 6: Hoglnd, L., L. Crpenter-Boggs, D. Grntstein, M. Mzzol, F. Perye, J. Smith, nd J. Regnold Orchrd floor mngement effects on nitrogen fertility nd soil iologicl ctivity in newly estlished orgnic pple orchrd. Biology nd Fertility of Soils. 45: Hogue, E.J., J.A. Cline, G. Neilsen nd D. Neilsen Growth nd yield response to mulches nd cover crops under low potssium conditions in drip-irrigted pple orchrds on corse soils. HortScience 45: Lyne, R.E.C., C.S. Tn nd D.M. Hunter Cultivr, ground-cover, nd irrigtion tretments nd their interctions ffect long-term performnce of pech trees. Journl of the Americn Society of Horticulturl Science 119: Killin, J. C. nd J. R. Meyer Effect of orchrd weed mngement on ctfcing dmge to peches in North Crolin. J. Econ. Entomol. 77: Mrschner, H Minerl nutrition of higher plnts. Acdemic Press. Sn Diego, CA Mrsh, K.B., M.J. Dly nd T.P. McCrthy The effect of understorey mngement on soil fertility, tree nutrition, fruit production nd pple fruit qulity. Biologicl Agriculture nd Horticulture. 13, Mercelle, R Minerl nutrition nd fruit qulity. Act Hort. 383,

24 Merwin, I.A. nd W. C. Stiles Orchrd groundcover mngement impcts on pple tree growth nd yield, nd nutrient vilility nd uptke. Journl of the Americn Society of Horticulturl Science 119: Meyer, R.D., J. Hsey, K. Klonsky, P. Livingston, nd A. Shresth Nitrogen mngement during estlishment of orgnic peches. ASA-CSSA-SSSA 2006 Interntionl Meetings, Indinpolis Nov Mills, H.A. nd J.B. Jones Plnt Anlysis Hndook II: A Prcticl Smpling, Preprtion, Anlysis nd Interprettion Guide. Micro-Mcro Pulishing. Athens, Georgi. p Mullinix, K. nd D. Grntstein Potentil nitrogen contriutions from legumes in Pcific Northwest pple orchrds. Interntionl Journl of Fruit Science 11: Neilsen, G.H. nd E.J. Hogue Long-term effects of orchrd soil mngement on tree vigor nd extrctle soil nutrients. Cndin Journl of Soil Science 72: Neilsen, G.H. nd E.J. Hogue Comprison of white clover nd mixed sodgrss s orchrd floor vegettion. Cndin Journl of Plnt Science 80: Nunez-Elise, R., H. Chn, L. Cldeir nd C.F. Severt Polypropylene row covers gretly enhnce growth nd production of fourth-lef sweet cherry trees. HortScience. 40:

25 Peck, G.M., P.K. Andrews, J.P. Regnold nd J.K. Feldmn Apple orchrd productivity nd fruit qulity under orgnic, conventionl nd integrted mngement. HortScience 41: Prker, M.L., J. Hull, nd R.L. Perry Orchrd floor mngement ffects pech rooting. Journl of the Americn Society of Horticulturl Science. 118: Prker, M.L., nd J.R. Meyer Pech tree vegettive nd root growth respond to orchrd floor mngement. HortScience. 31: Perez, A. nd K. Plttner Fruit nd Tree Nuts Outlook: Commodity Highlight. Orgnic Fruit nd Berries. USDA Economic Reserch Service. FTS-356SA Rmos, M.E., A.B. Roles, A. Snchez-Nvro, nd J.L. Gonzlez-Reollr Soil response to different mngement prctices in rinfed orchrds in semi-rid environments. Soil nd Tillge Reserch 112: Rowley, M.A., B.L. Blck, C.V. Rnsom, J.R. Reeve nd J.E. Creech Alterntive lleywys for trt cherry orchrds. Journl of the Americn Pomologicl Society 64: Sánchez, E.J., C.E. Edson, G.W. Bird, M.E. Whlon, T.C. Willson, K. Kizilky, J.E. Nugent, W. Klein, A. Middleton, T.L. Loudon, D.R. Mutch, nd J. Scrimger Orchrd Floor nd Nitrogen Mngement Influences Soil nd Wter Qulity nd Trt Cherry Yields. Journl of the Americn Society of Horticulturl Science 128:

26 Skroch, W. nd J.M. Shris Orchrd floor mngement: n overview. HortScience, 21: Slttery, E., M. Livingston, C. Greene, nd K. Klonsky Chrcterisitics of Conventionl nd Orgnic Apple Production in the United Sttes. USDA Economic Reserch Service. FTS Uth Deprtment of Agriculture nd Food Sorrenti, G., M. Toselli, nd B. Mrngoni Use of compost to mnge Fe nutrition in Per trees grown on clcreous soil. Scienti Horticulture 12: Stsik, M.J. nd Rom, R.C Suterrnen clover (Trifolium suterrneum L.). ground cover effects on growth nd folir nutrient sttus of young pech (Prunus persic (I.) Btch). HortScience, 26: Sullivn, T.P., D.S. Sullivn, E.J. Hogue, R.A Lutenschlger nd R.G. Wgner Popultion dynmics of smll mmmls in reltion to vegettion mngement in orchrd groecosystems: compenstory response in undnce nd iomss. Crop Protection 17: TerAvest, D., J.L. Smith, L. Crpenter-Boggs, L. Hoglnd, D. Grntstein, nd J.P. Regnold Influence of orchrd floor mngement nd compost ppliction timing on nitrogen prtitioning in pple trees. HortScience 45: Toselli, M., E. Bldi, G. Mrcolini, M. Qurtieri, G. Sorrenti, B. Mrngoni, nd A. Innocenti Long term (8 yers) effect of minerl nd orgnic fertiliztions on pech yield nd nutritionl sttus. Act Horticulture 962:

27 Tworkoski, T.J. nd D.M. Glenn Orchrd Floor Mngement Systems. In: The Pech: Botony, Production nd Uses. Eds D.R. Lyne nd D. Bssi. CAB Interntionl Uth fruit nd erry survey United Sttes Deprtment of Agriculture Ntionl Agriculturl Sttistics Office, Uth Field Office, Slt Lke City, UT Wlsh, B.D., S, Slmins, D.J. Buszrd nd F. McKenzie Impct of soil mngement systems on orgnic dwrf pple orchrds nd soil ggregte stility, ulk density, temperture nd wter content. Cndin Journl of Soil Science 76: Wng, H., C. Wng, X. Zho, nd F. Wng Mulching increses wter-use efficiency of pech production of the rinfed semirid Loess Plteu of Chin. Agriculturl Wter Mngement 154: Welker, W.V. nd D.M. Glenn Growth response of young pech trees to distriution pttern of vegettion-free re. HortScience 26:

28 Tle 1. Compost chrcteristics from 2008 to Compost Chicken Steer mnure chrcteristic mnure 2009 Steer mnure 2010 Steer mnure Totl N% C:N Rtio 7:1 13:1 12: P % K %

29 Tle 2. Averge nitrogen inputs for compost, fether mel, nd lley wy iomss mendments for six different orchrd floor tretments: living mulch tree-row with grss (LmGr) nd trefoil (LmTr) lley wy, strw mulch tree-row with grss (StGr) nd trefoil (StTr) lley wy, tillge tree-row with grss lleywy (TiGr) nd weed fric with grss lley wy (WfGr). Different letters indicte significnt differences t p Compost pplied Compost Fether mel Biomss totl verge Orchrd floor per tree totl N per totl N per totl N per N inputs per tretment (kg DW) tree (kg) tree (kg) tree (kg) tree (kg) 2008 LmGr LmTr StGr StTr TiGr WfGr LmGr LmTr StGr StTr TiGr WfGr LmGr LmTr StGr StTr TiGr WfGr LmGr LmTr StGr StTr TiGr c c WfGr c c Note: trefoil iomss ws mown nd lown into the treerow from 2009 on, however residue quntity ws only collected in

30 559 Tle 3. The effectiveness of tree-row orgnic weed mngement strtegies (n = 4), evluted sed on weed density (plnts/m 2 ) nd visul evlution of re ground (% cover) in 2010 in the orgnic experiment. Densities were determined from two 0.25 m 2 qudrnts in ech plot. Percent re ground ws visully estimted etween the three center dt trees. Tretment Weed densities (no./m 2 ) Bre ground (%) Tree-row Alleywy 4-My 27-Jul 29-Aug 29-Jun 27-Jul Strw Grss 20.5 d 37.5 c Strw Legume 56.5 c c 22.3 c Alyssum Grss c 13.3 c Alyssum Legume 46.5 cd c 12.2 c Tillge Grss d Weed fric Grss Anlysis of vrince (P) Block Tretment < < < < < Fctoril Tree-row Alley Tree-row x lley

31 Tle 4. The effect of conventionl nd orgnic tree-row mngement (n = 4) on weed control during the 2010 growing seson, s evluted y weed density nd visul evlution of re ground in the integrted experiment. Weed density ws determined from two 0.25 m 2 qudrnts in ech plot. Percent re ground ws visully estimted etween the three center dt trees. Tretment Weed density (no./m 2 ) Bre ground (%) Weed mngement Fertility 4-My 29-Jun 27-Jul 29-Aug 29-Jun 27-Jul Bre-ground NPK c c Bre-ground Compost Pper mulch NPK c 8.0 c 7.0 c Pper mulch Compost Anlysis of vrince (P) Block Tretment < < < < Fctoril weed mngement < Fertility < Weed x fertility

32 Figure Cptions: Figure 1: Trunk cross sectionl re over time (n = 4) for orgnic pech trees estlished in 2009 under different orchrd floor mngement systems: strw mulch grss lleywy (StGr), strw mulch trefoil lleywy (StTr), living mulch grss lleywy (LmGr), living mulch trefoil lleywy (LmTr), tilled tree-row grss lleywy (TiGr) nd weed fric tree-row grss lleywy (WfGr). Different letters indicte significnt differences mong tretments within yer t the level of p < Figure 2: Trunk cross sectionl re over time (n = 4) for pech trees estlished in 2008 under different integrted orchrd floor mngement systems: orgnic fertilizer conventionl hericide (OFH), conventionl fertilizer conventionl hericide (CFH), conventionl fertilizer conventionl hericide to strt trnsition to orgnic in 2011 (CFHT), orgnic fertilizer pper mulch (OFM), conventionl fertilizer pper mulch (CFM). Different letters indicte significnt differences t the level of p < Figure 3: Totl orgnic soil cron (0-10cm depth) in the orgnic experiment for lleywy min effect over time (n = 4) contrsted with orgnic weed free stndrds tillge nd weed fric. Different letters indicte significnt differences t the level of p < Figure 4: Totl soil nitrogen (0-10cm depth) in the orgnic experiment for lleywy min effect over time (n = 4) contrsted with orgnic weed free stndrds tillge nd weed fric. Different letters indicte significnt differences t the level of p < Figure 5: Min effect of fertilizer nd interction of weed control method with time in the integrted experiment on soil orgnic cron (n = 4). Different letters indicte significnt differences t the level of p < Figure 6: Aville (Olsen) soil phosphorus for tree-row min effect over time (n = 4) in the orgnic experiment contrsted with orgnic weed free stndrds tillge nd weed fric. Different letters indicte significnt differences t the level of p < Figure 7: Aville (Olsen) soil potssium for tree-row nd lleywy min effect over time (n = 4) in the orgnic experiment contrsted with orgnic weed free stndrds tillge nd weed fric. Different letters indicte significnt differences t the level of p <

33 TCSA (cm 2 ) StGr StTr c c c c LmGr LmTr TiGr WfGr Figure

34 TCSA (cm 2 ) OfH CfH OfM CfM Figure

35 Totl C (g kg -1 soil) Grss Trefoil Tillge Fric 603 Figure

36 Totl N (g kg -1 soil) Grss Trefoil Tillge Fric Figure

37 Orgnic C (g kg -1 soil) Orgnic C (g kg - 1 soil) Compost NPK Hericide 8 Pper Figure

38 P (mg kg -1 soil) Strw Living mulch Tillge 20.0 Weed fric Figure

39 K (mg kg -1 soil) K (mg kg -1 soil) c c c Strw Living mulch Tillge Weed fric Grss Trefoil Tillge Weed fric Figure