FINAL REPORT Preventing soil, water and nutrient limitations to sustainable, quality fruit production

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1 FIAL REPORT Preventing soil, wter nd nutrient limittions to sustinle, qulity fruit prodution Prinipl Investigtors: Denise eilsen, Gerry eilsen, Eugene J. Hogue, Sunghee Guk, Agriulture nd Agri-Food Cnd, PARC, Summerlnd, BC Peter Millrd, Muly Lnd Use Resoure Institute, Aerdeen, Sotlnd Co-Investigtors: Frnk J. Perye, Dn Fuion, Mike Bush, Wshington Stte University Tom Forge, PARC, Summerlnd/Agssiz, BC Funding History: Funding in :$5K, $55K, $58K Ojetives: 1. To determine effetive nd effiient use of nd wter in high density pple orhrds i. timing nd mgnitude of tree demnd for ii. effets of pplition rte, timing, nd rop lod on fruit qulity. To develop methods to overome poor tree growth on prolem soils i. vi soil mendments ii. vi surfe mulhes nd irrigtion mngement 3. To identify fertilizer strtegies for new ultivrs i. to optimize prodution nd qulity of fruit ii. to optimize lium nutrition of fruit Signifint findings: 1-1 requirements for young pple trees were low (8 to l/ ve. over the first six yers) nd supply of l/re exeeded demnd. Thus use effiieny ws often low (<3%). 1- In oth newly plnted nd estlished trees, erly spring fertilizer pplitions (pre-shoot growth) re not tken up y trees s growth is supported y remoilised. 1-3 The most effiient tree use of ws found for low rtes pplied - weeks fter loom when irrigtion ws sheduled to meet evportive demnd. 1- The timing of pplitions hd greter effet on fruit qulity thn rte. Lter pplitions elerted the onversion of strh to sugrs ut lso inresed idity. 1-5 Crop lod ws mjor ftor in determining fruit solule solids, mli id ontent nd sugr:id lne. Optimum rop lod for mintining size nd fruit qulity in Gl/M.9 ws round 5 fruit/m TCSA. -1 First yer growth of pple is inresed more y plnting young trees diretly into soil mended with n orgni ompost with high P ontent thn y pplying P-fertilizer in June with irrigtion wter. - Soil mendments, espeilly surfe mulhes, uffer ginst soil moisture hnges providing some protetion ginst minor, ut not mjor, ourrenes of wter stress. -3 Irrigtion type (sprinkler vs drip ) hd no effet on growth or fruit, even though drip trees reeived % less wter thn sprinkler irrigted trees. - Alflf hy mulh improved growth in nd 1, ut hd no effet on fruiting. -5 Lterl distriution of soil moisture is more even under mulh thn no mulh. 3-1 Pulsing high P onentrtion into the root zone in the week immeditely following full loom ontinues to look good in terms of inresing fruit yield in the first 3 fruiting sesons over 5 different ultivrs. 3- There ws deresed inidene of wter ore oserved for Fuji nd Silken fruit from the P-tretment in Applition of C sprys erlier thn normlly reommended gin prevented the development of ny C-relted disorders t hrvest for seond yer. Methods: 1. i), ii) Five field experiments involving high-density ( trees per re) plntings of pple on M.9 rootstok were used to investigte strtegies to improve mngement in orhrds. All experimentl plots reeived dily drip irrigtion nd pplied through the irrigtion system (fertigtion) with different regimes ording to the

2 experimentl design. Expt1. ws with Golden Deliious plnted in Three pplition timings with sequentil whole tree hrvests were undertken to determine timing of remoilistion nd root uptke. Expt. involved Gl plnted in 1997 nd the effets of timing nd rte of supply, nd rop on fruit qulity were mesured. Expt. 3 on Gl ws plnted in 1993 nd long with Expts. 1 nd ws used to lulte removl in leves nd fruit (tree demnd). Expt. ws plnted in 1999 nd used to determine timing of remoilistion, uptke nd the flux of in the xylem sp throughout the growing seson. In Expt. 5, Gl plnted in 1997 were treted with tmometer sheduled or fixed rte irrigtion to determine use effiieny nd retention in the root zone.. i) Breurn on M.6 rootstok (plnted 1998) ws used to test the effets of vrious soil mendments seleted for their potentil to improve the fertility or wter holding pity of these lomy snd soils. All tretments reeived dily drip irrigtion nd stndrd P-fertigtion (P pplied erly June). Tretments inluded: 1) Chek (unmmended soil), nd severl mendments rototilled to pprox. 8 inh depth in the tree row. These inluded: ) orgni ompost (9 tons/treted re), 3) ompost plus greenhouse vermiulite mix (1% soil volume), ) ompost nd zeolite (3% soil weight), 5) ompost nd entonite (3% soil weight) nd 6) vermiulite lone. In the seond yer, hlf the lok ws sujeted to wter stress (5% of norml sheduled irrigtion) in order to test the ility of the mended soils to uffer ginst the effets of wter stress. Throughout the study detiled reords were kept of tree growth, fruiting nd nutrition.. ii) Breurn/M.9 were plnted in Mrh, on ft x 8.5ft sping t Alln Orhrds, hes, WA. Irrigtion tretments were either drip pplied in response to evportive demnd mesured with n tmometer or ABSsprinkler pplied ording to grower shedule. ws pplied t low or high onentrtion in the irrigtion solution from My - Sept. Minimlly omposted diry solids were pplied t 5 tons/re- nd lflf strw mulh ws pplied t the rte of 56 tons/re in My. Eletroni monitoring of wter flow to eh tretment, tmometer evportion, soil temperture nd soil moisture using Wtermrk sensors () or Envirosn (1) ws rried out. Tree growth, lef SPAD levels nd lef nutrients were mesured in nd fruit yield nd qulity in 1. In 1, similr experiment with Breurn/M.6 nd vrious irrigtion, nd mulh tretments ws estlished t PARC, Summerlnd, in order to determine soil nd plnt nd wter sttus using vriety of tehniques inluding PCAP smplers, TDR, sp flow guges, stem wter potentil, stomtl ondutne nd photosynthesis. 3. i) Five new ultivrs (Gl, Fuji, Cmeo, Amrosi nd Silken) were plnted on M.9 rootstok in 1998 in high density plnting sped t 3ft in rows seprted y 1ft. Strting in 1999 nd for the pst 3 growing sesons, the lok hs een mintined in series of rndomized, replited fertilizer tretments, pplied with dily irrigtion with wter quntities sheduled throughout the whole orhrd lok vi tmometer in order to minimize tree wter stress. Tretments hve inluded low (8ppm) nd high (168ppm) nitrogen tretment, eh pplied t 3 different times fter loom inluding erly (first weeks postloom), mid-seson (-8 weeks postloom) nd lte pplitions (8-1 weeks postloom). Two dditionl tretments inlude: 1) high erly plus pulse of P (g per tree s mmonium polyphosphte (1-3-) in the week immeditely following loom nd ) high erly plus high oron (.5g per tree s Soluor) in the first four weeks postloom. Detiled reords of tree performne inluding vigor, yield, fruit nd lef nutrient onentrtion nd fruit qulity hve een olleted eh yer nd sttistilly nlyzed. 3. ii) In young Breurn plnting, suseptile to low C fruit, experiments were rried out to refine understnding of the timing of C sprys. In, three folir spry tretments of CCl (.5% CCl w/v) were pplied to runoff in rndomized, replited design inluding hek (no spry), five erly CCl pplitions (weekly Jun -Jul ) nd five lte CCl pplitions (weekly Aug 5-Sep ). In 1, the experiment inluded the hek tretment, five erly (first 5 weeks postloom), midseson (6-1 weeks postloom) nd lte seson (11-15 weeks postloom) CCl pplitions. Also lte seson pplitions of C suspension nd ph djusted C suspension were tested. Assessments were mde of fruit qulity t hrvest nd fter old ir storge nd of fruit C onentrtion t hrvest. Results nd Disussion: nd wter use 1. i) In irrigted pple orhrds the mgnitude nd timing of plnt demnd for, nd retention of in the root zone to llow root intereption re importnt ftors for effetive mngement of fertilizer. Results from five experiments in high-density plntings of pple on dwrfing (M.9) rootstoks re reported. Whole tree exvtion nd prtitioning (Expt.1) nd removl of in fruit nd senesent leves (Expt. nd 3) were used to ssess totl tree ontent (Tle 1) nd tree demnd (Tle ). itrogen requirements rnged from 8 to l/re over the first six yers fter plnting nd use effiieny ws often low (<3%), likely euse supply, l/re exeeded demnd. Annul growth is supported y remoilized from storge nd tken up y roots. In newly plnted trees (Expt. 1), root uptke of lelled fertilizer ws negligile during erly spring, nd growth in the first 6 dys fter plnting 5

3 (Fig.1) ws supported y the remoilistion of from woody tissue into new shoots nd roots (Fig.1). Uptke of fertilizer only ourred when remoiliztion ended nd shoot nd root growth entered rpid phse (Fig.1), suggesting tht fertilizer pplitions mde efore shoot growth ws initited, would likely e ineffetive. In estlished trees (Expt. ), remoilistion ws ompleted y petl fll (dy 1) (Fig. ) nd uptke y roots egn round full loom (dy 13)(Fig. ). Agin these findings suggest tht pplied efore loom nd efore the onset of rpid shoot growth is potentilly unville, prtiulrly if wshed out of the root zone y susequent irrigtion. This indites tht timing of supply to periods of high demnd is ruil for improving mngement. To understnd further the dynmis of remoiliztion in the spring, the mount of moving through the xylem t different times in the growing seson ws mesured using sp flow guges nd xylem sp nlysis (Expt. ). Previous experiments hve mesured hnges in onentrtion of vrious mino-ids (-trnsport ompounds) in xylem sp in ttempts to define remoiliztion, ut there re no reports of the quntity of trnsported in the literture. An exellent reltionship ws demonstrted etween spflow nd evportive demnd mesured y n eletroni tmometer (Fig 3). During remoilistion, mino id flux peked round full loom, fell to minimum round 3 weeks fter loom nd then inresed rpidly. (Fig 3). The mino-id, glutmine (Gln) my e useful s n inditor of remoilistion s it ws mjor omponent of totl moved up the xylem during remoilistion, ut not lter in the growing seson. To determine the effet of pplition timing on use, ws pplied t -, -8 or 8-1 weeks fter loom (Expt. ) t two rtes. The most effiient mngement system ws for trees reeiving low (5 ppm) fertigted supply, t to or to 8 weeks following loom (Tle 3). However, more ws removed in leves nd fruit thn ws dded, inditing tht the trees were using ntive soil to support growth. If this were to ontinue, we would expet tht reserves of soil would eome depleted. Comprisons were lso mde to determine the effets of irrigtion sheduled to meet evportive demnd nd irrigtion pplied t fixed rte on retention in the root zone nd tree utiliztion (Expt. 5). Wter losses eneth the root zone were greter for fixed rte thn sheduled irrigtion during the oolest months (My, June nd Septemer) of irrigtion pplition (Fig ). itrogen losses from the root zone followed similr pttern during times of fertigtion (My nd June) nd thus ws less ville for the tree (Fig. ). Consequently, greter use effiieny ws mesured for trees when irrigtion ws sheduled to meet evportive demnd rther thn pplied t fixed rte (Tle ). 1.ii) The effets of pplition timing nd rte on fruit qulity were mesured in for Gl/M.9 plnted in 1997 (Expt. ). In, three rop lods were superimposed on the experiment nd the effets mesured in nd 1. Despite the lrge differenes in the mounts of pplied t the different rtes (e.g. 1999; Tle 3), there were few effets of rte lone on fruit qulity (dt not shown). The timing of pplitions hd more effet on fruit qulity thn rte. Fruit reeiving lter in the seson (8-1 weeks fter loom) ws pprently more mture (higher solule solids nd less strh), thn fruit reeiving erlier in the seson. Fruit idity ws higher for ll fruits reeiving lte in 1998, ut only for those reeiving low, lte pplitions of in Higher fruit idity in response to lter pplitions of ppers to e independent of the inresed mturity (high strh index) whih ws lso oserved in response to lter pplitions of in These findings re importnt in view of urrent interest in the inlusion of qulity prmeters suh s solule solids nd potentilly idity in pple grding. Erly pplitions of likely hve low impt on fruit qulity euse lthough is tken up into shoot tissue from udurst onwrds (Fig 5), very little flows into the fruit until -5 weeks fter full loom, dy 16, (end of ell division) s illustrted in Fig 5. Imposed rop lods strongly ffeted fruit size, yield, solule solids nd idity in nd return loom nd fruit set in 1 nd these effets were greter thn those used y tretments (dt not shown). It is pprent tht rop lod is primry ftor in determining size nd some fruit qulity prmeters (solule solids nd idity) ut is not relted to others (olour, firmness, strh). Equtions relting rop lod to fruit size, solule solids nd idity n e used to determine optimum rop lods to hieve desired fruit qulity stndrds (Fig. 6). Overoming poor growth. i) First yer shoot growth ws improved for ll tretments reeiving the orgni ompost regrdless of whether other mendments were dded to the mixture (Fig. 7). The superior performne of this tretment ws ttriuted to its ility to supply P t the very erly stges of root growth sine trees were plnted into higher P environment resulting from the high P ontent of the ompost (see lef P, Fig. 7). Although susequent reserh hs indited dvntges to ddition of pulse of high P immeditely post loom for estlished trees, these results indite the dvntge of pling newly plnted trees diretly into high P environment. In the seond yer, the 5% of norml irrigtion (I) tretment resulted in soil moisture ontent to 5% lower thn the norml irrigtion tretment (I1) (dt not shown). Fruit size ws signifintly deresed for I trees (Fig. 9). Fruit 6

4 size ws lso redued for most of the soil mendment tretments with the possile exeption of the ompost plus zeolite mendment.. ii) In oth nd 1, trees t hes were not very vigorous. Totl extension growth rnged from 5 115in in nd from 6-15in in 1. Chnges in TCSA were lso low rnging from.1--.5in in nd.13-. in 1. There ws no effet of irrigtion method (sprinkler vs drip) on growth or fruit prodution even though trees reeived onsiderly different mounts of wter (Tle 5). Trees reeiving mulh hd greter extension growth nd inrese in TCA thn trees reeiving no mulh, ut there were no effets of mulh on either yield or fruit size (Tle 6). There ws no effet of the mendment (minimlly omposted diry solids) on growth or fruiting (dt not shown). Similrly, there were few tretment effets on fruit qulity (dt not shown). In, we speulted tht the enefiil effet of mulh ws prtilly due to improved wter reltions. Plnt wter stress ws ssessed t one smpling dte in August 1 using stem wter potentil nd photosynthesis mesurements nd there were no pprent effets of tretments. However, more frequent smpling is required to mke omplete hrteriztion. In July 1, Envirosn proes were instlled in two mulh nd two unmulhed plots. Mesurements indited tht moisture ontent within the soil profile (- in) ws similr for mulhed nd unmulhed sites. However,in generl, there ws more wter in the upper prt of the profile (-1in) under mulhed plots, nd previous studies y our group hve shown tht this is likely the lotion of the mjority of roots. In one of the un-mulhed lotions, moisture depletion (through dringe nd evpo-trnspirtion) oured in the top in of the profile nd the resultnt moisture ontent ws well elow permnent wilting point (1% moisture ontent) for over four weeks (Fig. 9). This indited tht there is onsiderle vriility in soil hydrologi hrteristis t this site. In similr study initited this yer t PARC Summerlnd, preliminry mesurements of soil moisture distriution round drip emitters under mulh (Fig 1) nd no-mulh (Fig 1) indited tht mulhes id in the lterl spred of soil moisture. In orse-textured soils, this my help redue trnsitory stress of roots t the oundry of the wetted zone during periods of high evportive demnd nd lso mitigted the effets of soil vriility. ew ultivr nutrition (phosphorus/lium) 3. i) The most signifint effet of tretments in the first 3 fruiting yers hs een the superior umultive yield performne of the phosphorus tretment whih hs produed more fruit nd higher yield of fruit per tree over ll 5 of the test ultivrs (Tle 7). Yield hs lso inresed from low to high rte ut to lesser extent thn the inreses ssoited with the phosphorus tretment. To present, the effet of the timing of pplition hs hd little effet on fruit yield. The effet of the P tretment hs een to mintin high lef nd fruit P onentrtion s indited in Fig. 11, whih ompres lef nd fruit P vlues during the study for the +P tretment nd P tretment, oth of whih lso reeived high erly in the seson. In generl, qulity of the fruit in this study hs een good with few hrvest or storge disorders oserved. In 1, the only hrvest disorder seen ws wter ore, on Silken nd Fuji. For oth ultivrs, the P-tretment redued inidene of this disorder t hrvest (Fig. 1). Inidene of wter ore ws lower for Silken ut ompletely eliminted in the P-tretment. Inidene of wter ore in Fuji pples ws redued to 6% reltive to other tretments where it rnged from 77 to 93% of fruit. Lef onentrtion hs delined over yers for ll tretments s rop lod inresed ut lso within eh seson s eh yers rop sizes. The pttern hs een oserved for ll ultivrs ut ws espeilly pronouned for Cmeo nd Silken. There were importnt growth differenes oserved mong ultivrs in the study, s indited y differenes in verge umultive yield (dt not shown). Cmeo nd Silken hve een most produtive while Amrosi hd the lowest yield over the first 3 fruiting sesons. Fuji hd intermedite yield ut only fruiting sesons. There hve lso een signifint differenes in lef nutrient onentrtion mong ultivrs despite ll ultivrs eing sujeted to the sme fertilizer tretments (dt not shown). Fruit C onentrtion is often the most importnt minerl ssoited with fruit qulity. Differenes in hrvest fruit C onentrtion of ultivrs were lso oserved nd summrized for the two yers (1999 nd ) for whih nlysis hs een ompleted (Fig. 13). Differenes in fruit C were oserved mong yers with onentrtions greter in thn 1999 for ll ultivrs. Cmeo nd espeilly Silken hd tendeny towrds low fruit C onentrtion lthough not so low s vlues mesured for n djent lok of Breurn pples of the sme ge. A ritil minimum threshold of mg C/1g FW hs frequently een used in British Columi. 3. ii) For the hrvest, lium sprys signifintly ffeted fruit C onentrtion nd Breurn fruit qulity (Tle 8). Lte seson C sprys were more effetive t inresing hrvest fruit C onentrtion thn erly sprys. 7

5 However, these erly seson C sprys ompletely eliminted the inidene nd severity of itter pit t hrvest nd fter 3 months old storge. Clium sprys pplied lter in the growing seson were effetive t reduing severity of itter pit fter old storge ut only modertely effetive t ontrolling itter pit ourrene t hrvest. Overll ourrene of itter pit ws lower in the lok in 1 (Tle 9). Highest inidene nd severity of itter pit ws mesured for fruit spryed with CCO 3 suspension, implying tht the reltive insoluility of this mteril my hve inhiited its uptke into fruit. The reltively lrge size of fruit in this tretment my hve lso inresed its suseptiility to itter pit development. It is noteworthy tht ll CCl tretments, espeilly the erly nd midseson CCl sprys, were free of ll C relted disorders t hrvest inluding inidene nd severity of itter pit, rowning nd lentiel pit (Tle 9). Although no signifint differenes mong tretments were oserved this yer for red olour t hrvest, lowest % red ws mesured fter pplition of CCO 3 suspensions. However this tretment redued sunurn to zero (from n verge of 3% this yer). Overll udget: Preventing soil, wter nd nutrient limittions to sustinle, qulity fruit prodution Denise eilsen Item Slries Reserh tehniin (L. Herert) 3K 3K 3K Tehniin support (I. Losso) 17K 17K 13K Tehnil ssistne (D. Fuion/Ykim) K K Professionl/tehnil ssistne (D. Eissenstt/Penn 5K Equipment Phone modem (hes) K Sp flow guges K Mterils nd Supplies K K K Trvel/Supplies 1K K Totl 5K 55K 58K MII mth This projet hs onsistently een supported y mthing investment inititive funds (MII) provided through the Cndin government. These funds hve een used to hire summer students ssigned to the projet nd to llow the purhse nd mintenne of equipment to expnd the nlytil pility of the group (eg. 15, Leo nd flow injetion nlysis systems). Totl udget: $165K Tles nd Figures: Tle 1. Totl nitrogen ontent of young pple trees on Mlling 9 (M.9) dwrfing rootstok dded removl Tle. Estimtes of nnul nitrogen requirements pple trees on Mlling 9 (M.9) dwrfing rootstok: itrogen removl in fruit nd senesent leves l/re oz/tree l/re z removl Golden Deliious/M.9 y first yer Gl/M.9 third yer Gl/M.9 sixth yer Golden Deliious/M.9 eginning first yer Golden Deliious/M.9 end first yer oz/tree.8.9 l/re z 6.7. Golden first ye Golden yer z ssumes tree density of 1336 trees/re y leves only z ssumes tree density of 1336 trees/re 8

6 Tle 3. Effet of timing nd rte of nitrogen supply on nitrogen inputs nd removl in fruit nd senesent leves for three yer-old Gl pple trees on Mlling 9 (M.9) dwrfing rootstok (Expt. ) Time of pplition dditions l/re 1 z removl l/re 1 Effiieny x 1 Tle. Wter nd dditions, removl in senesent leves nd fruit, growth, yield nd lef ontent of two yer-old Gl/M.9 pple trees reeiving irrigtion either pplied to meet evportive demnd (sheduled) or t fixed dily rte (unsheduled) (Expt. 5) Irrigtion Wter dded gl/tree dded oz/tree removed oz/tree T1 y % 7% Sheduled T % 39% Unsheduled T % 5% z 1 = 5 ppm nd = ppm nitrogen in the fertigting solution y T1 = -; T = -8; T3 = 8-1 weeks fter full loom x Effiieny = removl / dditions Tle 5. Effet of irrigtion method on wter use, growth nd fruit of Breurn/M.9 (hes) Tle 6. Effet of mulh pplition on growth nd fruit in Breurn/M.9 (hes) 1 1 Wter use (re feet) Extension (in) Chnge TCA (in ) sprinkler drip sprinkler drip Extension (in) Chnge TCA (in ) o mulh 61.1 Mulh 1. o mulh 89.1 Mulh Yield/tree (l) 5..5 Yield/tree (l). 5.1 Fruit size(l) Fruit size(l).6.63 Within rows nd yers mens followed y different letters re signifintly different Within rows nd yers mens followed y different letters re signifintly different Tle 7. Cumultive numer of fruit nd yield per tree of pples for seond-fourth lef (1999-1) verged over ll ultivrs (Amrosi, Cmeo, Gl, Fuji, Silken) utrient + P + B Tretment Rte high high high high high low low low Timing Erly Erly Erly Midseson Lte Erly Midseson Lte Cumultive numer of fruit/tree } } =16 = 99 Cumultive yield (pounds/tree) Tretment signifine ** **** } } =.9 =. Tle 8. Hrvest fruit size, red olor nd fruit C onentrtion nd inidene nd severity of itter pit t hrvest nd fter 9 dys old storge nd 7 dys t room temperture for Breurn pple s influene y timing of folir C, rop Tretment Red (%) Hrvest Fruit C Fruit Size (mg/1g FW) (g) Storge Bitter pit Bitter pit Inidene Z Severity Y Inidene Z Severity Y 1. Chek (no C) Erly C 3. Lte C S *** S *** ** * ** Z Inidene rnges from none (.) to 1% of fruit ffeted (1.) Y Fruit lssified s slightly (1), modertely () or severely (3) ffeted y disorder nd divided y ffeted fruit multiplied y numer of fruit in smple in order to ssess degree of disorder Mens followed y different letters signifintly different t the level of proility indited 9

7 Tle 9. Hrvest fruit size, red olor nd inidene of disorders for Breurn s ffeted y folir tretments, 1 rop Tretment Red (%) Fruit Bitter pit Browning Lentiel Pit size (g) Inidene Severity Inidene Severity Inidene Severity 1. Chek (no C) 71.. Erly CCl Midseson CCl Lte CCl CCO 3 suspension CCO 3 suspension (ph djusted) S S * *** S S S S Mens in olumns followed y different letters signifintly different t the level of proility indited Figure 1. Reltionship of pplition timing (1, nd 3) to () uptke of fertilizer (lelled) with respet to growth nd () remoiliztion of unlelled from woody tissue into new growth (Expt. 1) Dry weight (oz/tree) () Plnting dte April, 9th Shoot dry weight Dy of the yer Root dry weight Fertilizer uptke.1.5 Lelled (oz/tree) Unleled (oz/tree) () Plnting dte April 9th woody tissue shoots Dy of the yer roots Figure. itrogen ontent in () spur leves from remoiliztion nd () totl top growth from fertilizer (Expt. ) 3 5 () Spur leves 5 () Totl Remoilised ppm 1 ppm Fertilizer Dy of the yer Dy of the yer Figure 3. Trnsport of () trunk sp in reltion to evportive demnd nd () trunk sp mino ids over the growing seson (Expt. ) () () Sp flow (L/ tree /dy) ppm 15 ppm Atmometer evportion (mm/ dy) Amino idi flux through stem (mg /tree/ dy) Bud urst Asp Glu Asn Gln Arg Tight luster 1/" green Full loom Pink End of ell devision Dy of the yer 5

8 Figure. Sesonl () wter nd () losses eneth the root zone for two yer-old >Gl=/M.9 pple trees in response to irrigtion either pplied to meet evportive demnd (sheduled) or t fixed dily rte (unsheduled) (Expt. 5) () () Wter loss (gl/ tree) 5 5 Sheduled Unsheduled loss (oz/tree) Sheduled Unsheduled My June July Aug. Sept. Ot. Ot.-My My June July Aug. Sept. Ot. Ot.-My Figure 5. Inflow of into () shoot tissue nd () reprodutive tissue from ud urst to mid July (Expt. ) 6 5 () Shoot tissues 5 () Reprodutive tissues Totl ontent (mg) ppm 15 ppm Dy of the yer Dy of the yer Figure 6. Reltionship etween rop lod nd () fruit size, () solule solids, () fruit idity nd (d) sugr:id rtio (Expt. ) Fruit size (g) 3 () R = Solule solids(%) () R = Mli id ontent (g/1ml).5 () R = Fruit numer/tcsa ss/mli id rtio 36 (d) 35 R = Fruit numer/tcsa 51

9 Figure 7. The effet of soil mendment on first yer shoot growth nd lef P of Breurn on M.6 Totl Shoot Growth (m) Soil Amendment Tretments Chek Compost (C) C + Vermiulite C + Zeolite C + Bentonite Vermiulite Lef P (% dw) Figure 8. Averge size of Breurn fruit s ffeted y irrigtion nd soil tretments, seond yer plnted in April 1998 Fruit size (g) 6 3 I1 I Irrigtion Tretments Full irrigtion 5% irrigtion Soil Amendment Tretments 1 Chek Compost (C) 3 C + Vermiulite C + Zeolite 5 C + Bentonite 6 Vermiulite Totl Shoot Growth Lef P. I1 I Figure 9. EnviroSn plots for sites in mulhed nd unmulhed plots Mulh o Mulh Mulh o Mulh Figure 1. Sptil distriution of wter in the root zone () with mulh nd () without mulh () Soil m oisture (%) Dripper 3 ft Mulh + Drip, Sept1/1 3 S3 S 1.5 ft S1 () Soil moisture (%) Dripper o mulh +drip (Sept 1/1) 3 ft 3 S3 S S1 1.5 ft Figure 11. Averge midsummer lef P nd hrvest fruit P onentrtions s ffeted y +P tretment ompred to only tretment (-P), Figure 1. Inidene of wter ore in Silken nd Fuji fruit s influened y fertilizer tretment Lef P (% dw) d Lef Fruit Fruit P (mg/1g FW) Inidene of wterore t hrvest Silken Fuji. + P -P + P -P + P -P + P -P + P -P High Low High + P + B A A B C A B C 5

10 Figure 13. Fruit C onentrtion, verged over ll tretments, for Amrosi (A), Cmeo (C), Gl (G), Fuji (F) nd Silken (S) ompred to fruit C onentrtion of djent lok of sme ged unspryed Breurn (B) Fruit C onentrtion (mg/1g FW) 8 6 ritil threshold d A C G F S B A C G F S B. 53