S. Page-Dumroese,r Alan E. Harvey, Martin F. Jurgensen,: U Schoo S D A of Forest Forestry Serv and ce Wood ntermounta Products, n Research N/ ch gan Stat ...
Alan E. Harvey, Martin F.Jurgensen,:and lrichael J. Larsen DeborahS. Page-Dumroese,r I U S D A ForestServce ntermounta ldahoE3843.USA n ResearchStaton N4oscov'/ : Schoo of Forestryand Wood Products,N/ch gan Technolog ca Un versty HoLrghtonN4ch gan ,19931USA
to Planting-site SoilFumigation PineSeedlingResponse Ponderosa and FungicideApplication Abstract L.rlvs.) $rs ured as r biological odel Io determinethe etiects ol pl,rnling \ilc loil tir igati(rn Ponderos.rpinc (Prrr! r,'/"tr,J, .lnCliun!icidctIpplicationsonstockp1.lntedinnodcrl|ch"1ifilcsoilsoltheIntennounIlLiI\\reSt0 fumigation(V.rpln)lIcannenIs.singu|a||,'.andinconblnllion$iilrtungicide(I.ildimefinl)applic.ttiIS. Seedlings$ere signilic.rnLl)lrllcr rn control. cfo\ith ch.ractcrislics.nulririon. and ect(m)cofrhizal colonizalion $crc cvalLrated. rhe spdng fuig.Lrion treLrtmcnlrl lhc e.d of lbuf grlNing \e.rs(rs. Grc.rL.stcclonlcorrhizal col( iz.rtiorroccurred in the ron irrlnigatedneanrenr $ith fungicidc applicd bclbre pl:rnting Gener.rll). sprins or lrll irrrrigation trelt,nents. $irbout fungicide could applicadons. troduced the t|llesr sccdli.gs. These results sug-cestthrt soil fun1igalio. applications hef(ne oLrIplrLnling j'npro!eea|1!'pedi)|ftnce01p0.dcrosapineg'hen|efo|estingsiles$ilhrbunda!.natir'eeci(l|n}co||hiz] suggestslh.rIiffumig.tti0Iisjlllpractical.reductionof!egel|li!econpctili0nlna,"-gi\esimi|a|g|owlhg.lins'Elil1linljon|'n|I] nrtive ectonllcorrhizac in (hc nurser) Jnr,vimpft^e colonirtrtfun rlicr ounlanting.
lntroduction Ponderosapine (Pi?rJ ltondentsuLaws.) is an impofiantspecicson dry sitesin thewesternU.S.A. (LiDhart1988).Rapidachievemcnlof full stock ing tbllo* ing harvcstingis tiequently difficult firr ponderosapine. Most regencrationfailuresin the \\"ester-n U.S.A. rcsult from lolg periodsofevaporativedcnrandconbined *ith low soil moislure duringthegrorvingseasonlCurrisanclLynch 1957.). Low soil nutrientlcvcls. particularlynitrogen(N). oticn compound moisture problems (JurgenseD et al. 1986).Competitionfron invadingor rcsidual plant regr-o$'that'ter harvesl can further Leduceamountsof waterand nutrieDtsavailable (Miller 1987;Stewan1974). to conil'crrcgeneration Nonconifervegetationthat conrpcleswith tree therisk ofregencropsfbr moisturecanincrease eration failure and reducegrowth of cstablished stands(Bo)d 191J5). comnx)nsltc On siteswith scverecompetition. preparation practices(i.e.scalpingand burningl may not be adequateto rcduce invading herbaThcscsitesoftenmustbe repllinted ceousspecies. selcral timesbelbrestockingis rdequab for stand development(Cotl'rnan1982). Altemative methods to reduceseedlingmortrlity rnd/or increase grorvthduringcarly yealsmay giYelbrestersvaluableoptioDsin treatjngandregcncralingsuchsites. Optionscould includesoil fumigationbetbreplturting and/or sccdlingtreatmentuith fungicidcs bcforc plirnting.
Soil lirmigants are routinely uscd in barcrool lbrest ffee nurselymanNgcmcnlto decreaseweed and compctilion.eliminatesoil bornepathogens. reducenenatodeintection (Jamcsct al. I990; Tanakact al. 1986).Funigation usuailyresults in superiorseedlinggrowth in nurserysoils.which can continue after seedlingsare outplrnted (Benzian1965;Danielson andDavcyI9691Janes et al. 1990;Thiesrnd Paltm l97l). Klock (1980) usedmethyl bronide to tumigaleplantingspotsdur-ing a field stud)'in castcm Washington. Survivaland glorvthof Douglas-1ir l . P s e u d o t \ u gnot e n ; i e s i vi a r . , g l a r i c r{ rB e i s s I t . l Franco)anclponderosapire plaotedon thesedr! sitcsmorethandoubledconrparedto controlsatfcr 5 years.He speculatedthat fumigant induced c h r n ! e si n * ' i l h i , ' l o ! ) c f f e c l edJ i . e r s ef e . i . t J I ( e . soil nutrientavailabilit!.or ectomycorrhizrldc\\"erenot velopment.but dctailedmeaswelrlents taken(Bengtsonaod Smrrt l9lj I : Klock 1980). In the \\'esternU.S.A.. Vapam (sodiun N methyl-dithiocarbanate) is ofien used as a soil fumigant in forest nurseriesand may bc nrorc amenablelbr use in field outplantingsituatiol'rs sinceit docsnot requirethatthe soil be coveled Vapamis lessvola with plasticatier treatnrent. tilc thanothertlmigants,suchasmethylbromidc : l r ) di . r e ! i \ l ( r e Ll lr r rl u m i B r r t r ror fnp l , r n l i n i. i l c \ . While rcsullswere preliminary(first year).fumigationu'ith VapamproducedDouglrs-tirand rvesternrvhitepine (Pittustrutntk:oluDougl.ex. NofthwesrScieDce. Vol. 70, No. 2. 1996 . j l L r ! r 6 b lr l r . \ .
r r \ c n S c r d rr L i rA \ ( [ r . r
\ll.lliGir\.,r.d
139
D.Don) seedlingsu,ith increasedroot growth and total weight as conpared to seedlingsplantedin non-fumigatedsoil. Vapan fumigationalsoelimirated competing vegctation (Cornwal] 1985; Rainville1987).Howeveqchangcsin plantnutdtion or ectomycorhizalfunctionwerenotneasured. Application of triadirnelbn. l-(4-chloro phenoxy)-3.3-dimerhyl l-(1H-1.2,.1 triazol-t-yl)2-butanone. a systemic fungicide. inhibits ectonycorrhizal short root developmentin tbr(Southand Kelley 19ii2).Hou'ever, estnurser-ies Kelley ( 1987)notedthat after I year,greenhousegrorvn loblolly pinc (P&ls /.r.rddL.) seedlings treated with triadimefon had significantly more ectomycorrhizalshofirootsthancontlol seedlings. Survival and gro!\th of seedlingstreatedwilh tliadimcfonuere similarto controlsecdlingsaf tcroutplantinginto plantations(RowanandKelley 1986). Increasesin growtl] that continue even atter competingvegetationhasreoccupiedthe siteindicatc a basic changc in soil/tree root biologv. Applying triadirnefbnin thcnurserymayencouri,ige faster seedling root colonization by nativc ectomycorrhizal symbiontsafteroutplantingto a lbrest site. Thus. soil sterilization as a method lor conpetition contlol (both microbialandplant) and reductionofnon-nativeectonrycerrhizaemay havc an additive efllct and prove ct'fectiveregenerationtools.
1ir, lodgepolepinc (Plnris tontorta Doug1.ex Loud.)andwestemIarch(.Iarir o..identalisNrLt.) was clearedin 1985and the soil rototilledto a depthof30 cm. The soil is a coarse.loamy.mixed lrigid TypicXefochrcpt(Soil SurveyStaff l975). Meln annual precipitation and temperatureare 84 cm and 6.6" C, respectiveiy.Approximately 80% of the precipitationtalls as snow (Wellner t9'76).
StudyDesgn A ranclomizedcompleteblock dcsign was establishedon thissitein l988, with threereplications offive treatnentsand an untrcatedcontrol.Treat mentsconsistedof: (1) tall soil fumigationwith Vapam'. (2) spring soil fumigarioDwirh Vapam. (31 lall soil lumigation with Vaprm and triadimefonappliedto seedlingsin the greenhousebefore outplanting. (4) tall soil funrigariol with Vapam and rriadimefonappliedto seedlingsin the greenhousebetbre outplanting plus firur additionaltimest.hroughout the first growing season. (5) no soil lumigationandtriadimefonapplied to seedlingsin thc greenhousebefbre outplanting.
The objcctivesof rhis studyu'ereto: (1) exanrinetheimpactof plantingsitefumigationwith Vapamand fungicide applicationsof triadimcfon on survivalandg[owthponderosa pinc seedlings. and(2) detcrmineseedlitgcctornyconhizal colonization,height,diameter,andnutrition,andevalualesoil amtnoniumandnitratelevelsin a noderatelyfertiJc,tbrestedenvironmentrvith high levels of nativeectonycorrhizalinoculum.
Seedlingstreatedwith fungicide beforcplant ing (treatments 3.4, and 5)had rriadimefonapplicd threetimesat 2-weekintervals.while actively gro\r,ing in the greenhouse.Triadimefon wasselected because ofits suppressive effccton ectomycorrhizae developmenton pines(Man and Cordell 1987).The concentration was 1.8ng acrive ingredient/seedling mixed with a surfactant(MaIX l98?). Plotswere30 m * 30 m in sizewith a 1 m bufter.
Methods and Materials
SoilTreatment App cation
S te Descript on
Fall and spring soil fumigations were achieved with ,150ml/mr of Vapamafier thc soil had been soakedto a depth of 30 cm by rain. Vapam was appliedusirg a l0liter wateringcan.Treatcdareas were water-sealed(surlace soil soakedrvith walcr) to move thc Vapam into the soil. Fall fumigation plots were treatcdthe secondweek of October(1988).The soil wascoveredwith black plasticuntil4 weeksbeforespringplanting.Spring lumigation plots were trcated approximately 6
The studysitc is locatedal an elevationof 800 m oD lhc PriestRiver ExperintentalForest l9 km N of PriestRiver.ID. U.S.A. The previousstand whiclrconsistedof westemwhitepine,Douglas' lhc usc of tfade or tirnr nlmes in $is papcr is fir| feader r . l o r n a t i o n a n d d o c s n o r i r n p l v e n d o r s c m e nbr ) t h e U . S . I)cpaineDt ofAgricLrhure of an\ producr or sefvlce.
1.10 Page Dumroese.Harvey, Jurgensen,and Larsen
weeks befbre planting(1989.).The plots $'ere coveredwith blackplasticlbr 2 weeks.but wcre uncoveredfor'1 u'eeksbefore planting to allo$' the funigant to dissipate.Control plots were cov eredrt the sametimc springt'umigationplots\\,ere covered.Plots were covered*ith black plastic so they \\,ould be uncovercda unifom time bel h r ep l J n t i r r sP. l . ' r \\ c r e l e . l < dl b r i l n ) r e m u i n i n g f u r i g a n th ) p h n t i n i h i : h l y . e n . i t i re t , ' m r t , ' plantsas an indicator I week before seedlings wcrc outplaDted.Plots \\"erephnted with 100 I yr-oldcontaincr-grown ponderosa pine seedlings onalbylmspacing. rements Seedling Sampling and l\,4easu Beforeoutplanting,5 seedlingrool systensfrom eachtreatment$'ereexaminedfor ectomyconhizal r L l o tl i p \ . A c t i \ e e r l ( ' m \ c r r h i , / i irlo o l l i p 5c o m pised approximatcly I 0 percentof the r oot system in eiichtreatmcntcxceptthetdadimelbntreated seedlingswhich had nonc.After budsetof the lirst and secondgrowing seasons,5 scedlingsfiom cach treatmentand replicationwcrc carefully excrvated.Top height, rooting depth. and rootcollar diameteru ere measured.Topsof seedlilgs were severedfiom the roots.dricd al 60" C for 2:1 h. u,eighed,and ground to passa 20 mesh sieve. Seedlingshoots(rtem, branches,and needles combined)were prepared1br analysisofTotal N (P) by Kjeldahldigestionmethand phosphorus ods using the salicylic acid-sodiunrthiosulfate modification(BremnerandMulvaney 1982).Thcy rvcre analyzedon an Alpkenr Rapid Flow Ana lyzer ll Model 300. Calcium (Ca) and magne sium (Mg) u,ere analyzedby trlomic absorption (K) wasanalyzcdby fl ame potassiurn spectroscopl,, emissionafter sampleshadbeendry ashedat.l50" C and leachcdwith 2\ HNO.. Alter seedling rootswerewashcd.totalectomyco[hizaltips were Roots countedwith a 20x binocularlnicroscope. wcrc subsequentlydried rt 60" C tin 2.1h and weighed. So Samplng and Anays s Five 20 g random soil corc sampleswere collecteclk) a deplhof l5 cln in eachtreatmentreplication I d befbrefumigation.and 14 and.15d afier funigation. They were sievedto pass a 2 mm screen.Control soil sanples were collected rt the sametine as the t-alllumigation samplcs. Undriedsoil sampleswereextractedusing 1N KCI tbr ammoniunl-nitrogenandnitrlrteandanal,vzed
nitrogcnusingan Alpkem RapidFIow Analyzer II Model 300 (Keeneyand Nelson19821. Stat stical Ana ys s Thc significanceof dilferenceanong treatmenls was testedusinga one-wayanalysisof variance (ANOVA) tbr a ranclomizedcompleteblock de sign tbllowed by Scheffe'smultiple rangetest (Scheffe 1953).A type I error rate of p 3 0.05 wasapplicd.
Resultsand Discussion Seedng GrowthCharacteristics After the first gro\\,inlgseason.height growth was grealestiu the fumigation only trcatments.and least in the iall fumigation treatmentwith coD tinuoust adimeforapplicatien(nrble 1). Rooting depth through year four was unaftectedby thesefeatments(datanot shown).Survivalaticr the llrst growing seasonwas 707c in the control. treatnent. 717r in the no fumigation-triadinefon R 5 ' : i n I h e h l l l i t m i g r t i u nr r n r lr ' , , t t t i n u l u . triadimefbntreatment,87%in the fall luniga tion pre-plaDttriadinetbn treatment.904/rin the tall fumigationtrcatment,and96*,in the spling fumigation treatment.Root-collar diameter was grcatestin the fumigation only treatnents. Sec ond-yearseedlin-qgrowth was similar to the 1lt.st ycar. Seedlingsgrowing in the tumigated treaF ments had greater hei-qhtgrowth. root growth. cliameLer, and biomassthan the other trgitments, but, as with the tirsflcar, the dit'ierenceswefe not always signiflcant. By the end of the ti)urth growingin the springfuni season the seedlings gation plots had significantlSrgreaterheight than thosc in the other treatments(Table 2). Springfumigationbetbrcoutplantingmay proyide the necessary environment(i.e. control of residentfungi adverselyaflecting root systcms) fbr improveclsccdling growth. Fall funigation may allow recolonizationofthe soil belirrespring havenotcdstriking outplanting.Otherinvestigators increasesin seedlingheightand biomassin 1ir nrigatedsoil comparedto conffols that were not fumigated(AndersonandLibcna 1992;Com*all 1985:Hendersonand Stone 1970;Jarneset al. 1990;Klock l9li0; Rainville1987). T h e r ' r r srtr f u . r n gV i r p c nar c r o s \ : l ne n t i r e\ i l e rnay bc prohibitive ($2470lha) (Landis xnd Campbell1989).However.soil tumigationas a PorderosaPine SeedlingResponse 1,11
'IABLE
l. ciro\\'th chaructefislicsof pondcro\r finc seedlingsrs affecrcd by sjtc rre tmenr one and r\ro vears attef trcrtment. ( n = 2 0f o r y e r r I a n d n = l o f o r l e u : ) Year I
Year :
Crliper (mllli
T0tal Biomass (e)
l8.rr (0.-rl"
.l.7.rb (0.2)
6.0ab (0..1)
36.1,1
F N l lt u m i g a t i 0 n
l 8 . lr L i().3)
5.2a ().1)
6.la i0.:r)
1 19 a (0..1)
Fall llllligatjon |ncl rriadnnefon
ll 6rb
'1.5rbc (0.2)
6.2a (0..1)
ll.7rL (l).'l)
Fall fumigatior.rnd c o n t i r ( ) u st i I d i m e f o n \
().t) r6.8b i0.3)
-ll.5rLb i0.9) l2 -rb (1.9)
.19.9a 13.2) 15.7ab (l.l ) .11.4ab (l.l)
.1.6ab (0.1)
5.7ab (0.,r)
:ll.7ab (0.9)
11.8r (0..1)
.11.lab (1.:)
N o f u m i g u t i o na n d t r i a d i m e l 0 n
17..1lb
(0.t)
-l.Ec (0.3)
5.1b 0.3)
30.8h (0.9)
10.0b (a).,+)
3,1.9b (3.3j
17.6ab (0..1)
:r.:+bc (0.-l)
5.2b (0.'1)
33.2ab (0.9)
I l.8a
,12.9b
Heighl S p r i n gl l n i g a t j o n
Control
Height (cn)
(0.el
Caliper (mlll)
t2.1,t (0,1)
()..r)
Tdal Bi0nas! (g)
(-r.2)
rcontinuous triadllnet()n duing Iear I t)nl). tsDittefenliclters i.dic.rte signilic nt dilicrences (p
