Suoseur Finnish Petlnd Soiety ISSN 39-5471 Helsinki 216 Suo 67(2): 53 66 Suo 67(2) Tutkimusrtikkelit 216 53 Pet sh nd iotite in fertiliztion of Sots pine on n fforested utwy petlnd Turvetuhk j iotiitti männyn metsityslnnoituksess suonpohjll Jyrki Hytönen, Lsse Aro, Jorm Isskinen j Mikko Moilnen Jyrki Hytönen, Nturl Resoures Institute Finlnd, Silmäjärventie 2, 691 Knnus, Lsse Aro, Nturl Resoures Institute Finlnd, Itäinen Pitkäktu 3, 252 Turku, Jorm Isskinen, Rtpellontie 11, 915 Muhos, Finlnd Mikko Moilnen, Nturl Resoures Institute Finlnd, Pvo Hvksen tie 3, 914 In Finlnd pet is used in power genertion, often urned with wood mixture resulting in mixed sh types. Pet sh is usully rih in phosphorus (P) ut poor in potssium (K) nd thus not s good fertilizer for petlnd forests s wood sh. In this study we ompred the effets of pet sh nd pet sh with dded potssium (potssium hloride or iotite) on the growth nd nutrition of Sots pine seedlings on utwy petlnd. In ddition, pet sh ws pelletized with iotite in one tretment. The tretments were pplied round single trees with 1 replitions. The study site ws rih in N, ut poor in P nd K. Pet nd folir smples were nlysed, nd the height growth of seedlings ws monitored for 17 yers following the tretments. Pure pet sh hd positive effet on the growth of Sots pine ut the survivl rte of seedlings ws not stisftory. Pet sh enrihed with potssium inresed sustntilly growth of seedlings nd inresed the folir K onentrtion ompred to unfertilized ontrol nd pet sh lone. Pelletized pet sh nd iotite gve similr results s the use of un-pelletized pet sh nd iotite. Pet sh lone is not reommended for fertiliztion of Sots pine stnds on drined petlnds. Adding K to pet sh enles reyling of lrge mounts of nutrients k to petlnd forests, nd is good lterntive to low-solule P nd K fertilizer. The grnultion of the produt would ensure good spredility. Key words: Cutwy petlnd, potssium, iotite, potssium hloride, nutrition, Sots pine Introdution Ash is ommonly lssified ording to its prent mteril, whih lso indites the si differenes in nutrient ontents. Ash ontins plnt nutrients in the form of si ompounds. Thus, it ts oth s liming gent, reduing soil idity, nd s fertilizer, supplying nutrients to plnts (Srel 1991). Vrition in the nutrient onentrtions of sh of different kinds n e quite wide. The reyling of wood sh, espeilly rih in phosphorus (P) nd potssium (K) s
54 Hytönen et l. fertilizer hs een studied quite intensively for severl dedes nd reserh results show tht the use of wood sh hs severl dvntges, e.g. promoting tree growth nd nutrition, nd revers- Ekelund 24, Pitmn 26, Huotri et l. 215). In Finlnd nd other ountries hving rih pet resoures, pet is lso used in energy genertion in power nd heting plnts. Pet onstitutes 5 7 % of the totl energy onsumption in Finlnd. Pet nd wood re often urned s mixture, resulting in mixed pet nd wood shes. As y-produt 35, tonnes of pet sh nd mixed pet nd wood sh re formed nnully (Moilnen 29). Reyling of the nutrients ontined in pet sh, now mostly disposed off s wste, ould e n interesting lterntive for improving the nutritionl sttus of soils. Pet sh, s it is rih in phosphorus (P), is potentilly suitle fertilizer for forests where P is the limiting nutrient for tree growth. Thus, pet sh n serve s slowly solule phosphorus fertilizer in petlnd forests (Silfvererg & Isskinen 1987, Isskinen et l. 1994, Moilnen et l. 212). On the other hnd, it is poor in other essentil nutrients nd ontins, e.g. onsiderly smller mounts of potssium (K), lium (C), mgnesium (Mg) nd oron (B) thn wood sh (e.g. Moilnen & Isskinen 23, Mndre et l. 21, Silfvereg et l. 21). The K ontent of pet sh is often less thn 1% of the K ontent of wood sh (Silfvererg 1996). For this reson pet sh hs een onsidered to e n inferior lterntive to wood sh s n dditionl nutrient soure for trees (Isskinen et l. 1994, Moilnen & Isskinen 23). However, even though less thn wood sh, pet sh hs lso improved the nutrient sttus nd growth of Sots pines on petlnds, espeilly t high rtes of pplition (Silfvererg & Isskinen 1987, Isskinen et l. 1994, Moilnen et l. 212). Smll positive growth responses hve een reported in greenhouse studies (Moilnen et l. 1987, Srel 1991), in pot studies onduted outdoors (Mndre et l. 21), nd in petlnd forests (Silfvererg & Isskinen 1987, Isskinen et l. 1994, Moilnen et l. 212). Pet sh hs lso elerted the initil development of downy irh (Betul puesens Ehrh.) (Huotri et l. 28, 29), nd t high pplition rtes (5 Mg h -1 ), growth of silver irh (Lumme 1988) nd energy willows (Hytönen 1998) on utwy petlnds. Besides the low K ontent of pet sh, the lower soluility of K in pet sh ontriutes to the low vilility of K following pet sh fertiliztion (Nieminen et l. 25). Pet sh lso dereses soil idity (e.g. Moilnen & Isskinen 23), ut ompred to dolomiti limestone or wood sh, the pplition rtes of pet sh should e muh higher in order to hieve the sme effet (Jokinen 1982, Srel 1991). In Finlnd, shortge of phosphorus nd potssium n limit foremost the growth of trees these nutrients re ommon (Kunisto & Tukev 1984, Moilnen et l. 25, 21, Pietiläinen et l. on thik-peted, originlly treeless or sprsely treed fens (e.g. Kunisto & Tukev 1984). Tree growth prolems re used y the shortge of P nd K nd the imlne with the undnt nitrogen (N) (Kunisto & Tukev 1984, Moilnen 1993, Silfvererg & Moilnen 28, Moilnen et l. 21, Moilnen et l. 215). For exmple, in study y Moilnen et l. (21), every seond experimentl stnd on drined petlnd ws suf- were most undnt in deep-peted nd N-rih sites. On utwy petlnds even more severe nutrient imlnes re typil (Aro et l. 1997). In forest fertiliztion potssium hs een minly pplied s wter-solule potssium hloride (Moilnen et l. 25). The durtion of the effet of potssium hloride fertiliztion hs een shown to e. 15 yers when the mounts suggested in the reommendtions re pplied (Pietiläinen et l. 25). However, lso slowly solule forms of potssium ompounds (e.g. iotite nd phlogoite) hve een tested in forest fertiliztion trils (Moilnen et l. 25). Biotite is silite forming lrge plty minerl (K(Mg, Fe) 3 AlSi 3 O 1 (OH) 2 ) nd does not ontin wter-solule potssium. Potssium ions re nd re only prtly relesed y tion exhnge retions tht depend on the mount of tions
Suo 67(2) 216 55 present in the soil. They hve een shown to inrese folir K onentrtion initilly slower thn potssium hloride (Kunisto et l. 1993, Moilnen et l. 25). The durtion of the fertiliztion effet with slowly solule potssium fertilizers hs een shown to e t lest 19 25 yers nd thus longer thn hieved with esily solule potssium hloride (Kunisto et l. 1993, 1999, Moilnen et l. 25). to hndle nd its trnsporttion nd spreding in (Juntunen 1982). Nowdys lmost ll sh used in forestry is stilized, nd spred mostly in grnulted form or smller mounts s pelletized or self-hrdened forms. Stilizing ould redue the lehing of nutrients. For exmple, y using stilized wood sh the possile shok effets of high ph re onsidered to e voided (Steenri et l. 1999). K is the most solule nutrient in hrdened wood shes, ut its loss rte from hrdened sh is somewht lower thn from loose sh (Eriksson 1998, Nieminen et l. 25) due to formtion of slower soluility ompounds during the grnultion proess (Steenri et l. 1999). However, in K relese etween self-hrdened sh grnultes nd loose sh. In the grnultion proess sh ould e improved y mixing different kinds of shes or dding nutrients (Hytönen 1998, 1999). Pet sh omplemented with fertilizers ontining K ould e n exellent fertilizer for petlnds (Moilnen et l. 212). Sine pelletizing nd grnultion of sh is nowdys generl proedure, the pet sh nd iotite ould e dded in the proess. We hypothesized tht mixing iotite ontining slowly solule K with pet sh would inrese the usility of pet sh s fertilizer y inresing K nutrition nd growth of pines in Mteril nd methods The study re is loted in Vl, in the Pelso ws relesed from pet hrvesting in 1992. The pet thikness in the re ws 38 m on verge nd vried from 13 to over 1 m. Afforesttion ws done y plnting one-yer-old ontinerized Sots pine (Pinus sylvestris L.) seedlings in spring 1997. A fertiliztion experiment ws estlished in spring 1998. The verge temperture nd preipittion in the summer months (June August) during the study period ws 14.2 C nd 211 mm, respetively (Fig. 1). unfertilized ontrol (), 2) pet sh (PA), 3) pet sh + potssium hloride (PA+Ks), 4) pelletized mixture of pet sh nd iotite (PA+Bip) nd 5) un-pelletized mixture of pet sh nd iotite (PA+Bi) (Tle 1). The pplition mount of P ws 42 kg h -1 in ll fertiliztion tretments. K mount in the pet sh tretment ws 12 kg h -1 nd in tretments where potssium hloride or iotite ws dded to pet sh it ws 112 kg h -1 (Tle 1). Pet sh originting from the Hpvesi power plnt using exlusively pet, ws used t rte of 4, kg h -1. Nutrient ontent of sh ws: P 1.4 %, K.31 %, C 7.8 %, Mg 1.7 %. Biotite originted from Siilinjärvi (K 5 %, C 7 %, Mg 1 %). Potssium hloride (K 49.8 %, Mg.1 %) ws pplied t rte of 2 kg h -1 nd iotite t rte of 2, kg h -1. The pellets ontining wood sh nd iotite were mde with smll pelletizing mhine (Tklo 1997). The experiment onsisted of 5 experimentl plots (single tree plots) with smple tree in the entre. Dimeter of the plots ws 1.6 m (A = 2 m 2 plots in rndomized lok design with ten replitions. Fertilizers were spred round seedlings in the plots in the eginning of June 1998. The seedlings were numered. The totl height nd height growth of the trees were mesured t n ury of 1 m. Mesurements were done in utumn 2, 21, 22, 23, 24 nd 214. In 2 nd 23 lso the se dimeter of the seedlings ws mesured nd in 214 dimeter t rest height ws mesured. The numer of needle ge lsses in the min stem of the pines ws ounted from eh tree in 2 nd 23. At the sme time lso the length of urrent-yer needles ws mesured from the middle of the youngest shoots. All trees were ssessed for visul symptoms 17 (214) growing sesons following fertiliztion.
56 Hytönen et l. 35 25 Amnnul preipittion, mm 3 25 2 15 1 5 Preipittion Averge preipittion1987 214 Temperture Averge tempeture 1987 214 1996 1998 2 22 24 26 28 21 212 214 Yer 2 15 1 Annul men temperture, o C Figure 1. Annul men temperture nd preipittion in June August during the study period nd verges for 1987 214 on the fertilistion experiment of utwy petlnd in Vl. Kuv 1. Kesä-elokuun vuotuinen keskilämpötil j sdemäärä tutkimuksen ikn sekä keskirvot jnjksolle 1987 214 Vln metsityslnnoituskokeell. Tle 1. Fertiliztion tretments in the Sots pine seedling stnd experiment on utwy petlnd in Vl, northern Finlnd. Tulukko 1. Lnnoituskäsittelyt suonpohjlle perustetull männyn metsityslnnoituskokeell Vlss Pohjois- Suomess. Amount of nutrients Tretment, Käsittely Rvinnemäärät (kg h 1 ) P K C Mg Control PA Pet sh 42 12 312 68 PA+Ks Pet sh + potssium 42 112 312 68 hloride PA+Bip Pet sh + iotite pellet 42 112 452 268 PA+Bi Pet sh + iotite 42 112 452 268 yellowing needle tips of the previous yer needles nd in severe ses needles of the whole shoot hs visile symptoms (Reinikinen et l. 1998). Current-yer needle smples from the upper whorls were tken from the southern side of the trees. Smples were tken fter six (Deemer 23), ten (Novemer 27) nd 17 (Novemer 214) growing sesons following fertiliztion. The smples were tken from eh living tree nd omined to form four (23, 27) or three (214) replites. The smples were ompletely dried t 6 o C nd ground. The N ontent ws determined using the Kjeldhl method, nd totl P nd B were nlysed spetrophotometrilly from smples tken in 23 nd 27 (Hlonen iron (Fe), mngnese (Mn), nd opper (Cu) were determined y tomi sorption spetrometer. The smples tken in 214 were nlysed fter wet digestion in mirowve oven y ICP, nd C nd N onentrtions of needles were nlysed using CHN nlyser (Leo CHN2). Interprettion of the needle nlyses ws nd optiml onentrtions of different nutrients in the needles of Sots pine on drined petlnds in Finlnd (Prlhti et l. 1971, Reinikinen et l. 1998): Nutrient Poor Adequte Optiml Unit N < 12 12 13 13 18 mg g 1 P < 1.3 1.3 1.6 1.6 2.2 mg g 1 K < 3.5 3.5 4.5 4.5 5.5 mg g 1 B < 5 5 1 1 3 mg kg 1 Pet thikness ws mesured lose to eh tree. Volumetri pet smples were tken from 1 m pet lyers from four unfertilized plots in Novemer 23 (eh smple ws omposed of four susmples). The smples were dried t 6 C nd ground. The sh ontent of the pet ws 11 %. The N onentrtion ws nlysed with the Kjeldhl method, totl P spetrophotometrilly with the vndo-molydte method, B onentrtion spetrophotometrilly nd totl P, K, C, Mg, Mn nd Cu ontents with n tomi sorption spetrophotometer. In the 1 m lyer the men mount of N ws 3755 kg h -1,
Suo 67(2) 216 57 P 99 kg h -1, K 8 kg h -1, C 19 kg h -1, Mg 18 kg h -1, Fe 1429 kg h -1, Mn 3.8 kg h -1, Zn.6 kg h -1, Cu.2 kg h -1 nd tht of B.1 kg h -1. studied using IBM SPSS 22 sttistis softwre. When testing the effet of fertiliztion tretments on tree height nd the nutrient onentrtions, time nd tretment-y-time intertion effets were tested using repeted mesures ANOVA model. Originl height of seedlings, mesured just efore fertiliztion in the spring of 1998, ws used s ovrite when testing the height of seedlings. In the nlysis lso pet thikness ws tested s Sine in the repeted ANOVA models the Muhly s test indited tht the ssumption of spheriity hd een violted, the degrees of freedom were orreted using Greenhouse-Geisser estimtes of spheriity. The folir nutrient onentrtions were tested y one-wy ANOVA seprtely for eh smpling yer. Tukey s test ws used to test differenes etween mens using the.5 level of vrine stilizing trnsformtion of squre root rsine ws used, nd for tree volume squre root trnsformtion ws used. Results Mortlity of seedlings During the study period some of the seedlings died, ut only in ontrol or pet sh tretments (Fig. 2). Three yers fter fertiliztion 1 % of seedlings hd died in the pet sh tretment. In other fertiliztion tretments no mortlity hd ourred. During the following three yers, i.e. six growing sesons from fertiliztion, mortlity in the ontrol nd pet sh tretments ws 22 nd 31 %, respetively. The effet of tretment ws 11 yers mortlity inresed only in the ontrol tretment. Tree growth At the end of the study period the men height of unfertilized living seedlings ws 2. m (Fig. 3A). Mortlity of seedlings, % 5 4 3 2 1 3 yers 6 yers 17 yers F 3yr. = 1., p =.461 F 6yr. = 9.79, p =.4 F 17yr. = 118.933, p =. PA PA+Ks PA+Bip PA+Bi Figure 2. The perentge of ded plnted Sots pine seedlings 3, 6 nd 17 yers fter fertilistion tretment. For tretments, see Tle 1. Kuv 2. Kuolleiden männyn timien osuus 3, 6 j 17 vuott lnnoituskäsittelystä. Käsittelyjen kuvus tulukoss 1. with other fertiliztion tretments (Fig. 3A). The seedlings were tllest when they were fertilized with pet sh with dded potssium hloride (4.5 m) or iotite (5.2 5.4 m). Tretments inluding from eh other. The order of the growth rte in the tretments ws similr throughout the study. with pet sh nd potssium hloride grew s well s those fertilized with pet sh nd iotite (Fig. 3B). Lter, seedlings fertilized with pet sh nd potssium hloride were growing t lower rte. Aording to repeted mesures nlysis of vrine, the yer-tretment intertion on the height of the Fertiliztion lso ffeted rest height dimeter (D 1.3 ) of trees (Fig. 4A). The D 1.3 of trees on the unfertilized plots t the end of study period ws 2. m nd on fertilized plots from 4.9 m to 8. m, depending on the tretment. All tretments inluding K inresed the dimeter growth The men volume of living trees ws lowest on the unfertilized plots (Fig. 4B). In the tretment fertilized with pet sh the men volume of tree ws two times higher thn without fertiliztion. When potssium ws dded to pet sh either s potssium hloride or iotite, men volume of trees ws 4 5 times higher thn tht of unfertilized trees. Pelletizing of pet sh nd iotite did not
58 Hytönen et l. Men height of seedlings, m 6 5 4 3 2 1 A PA PA+Ks PA+Bip PA+Bi Annul height growth of seedlings, m 1996 21 26 211 Yer 5 B 45 4 35 3 25 2 15 1 5 1996 21 26 211 Yer Figure 3. Men height (A) nd nnul height growth of pine seedlings (B). Fertilizers were pplied in spring 1998. Tretments mrked with the sme letters in A do not differ from eh other ording to Tukey s test t the.5 For tretments, see Tle 1. Kuv 3. Männyn timien keskipituus (A) j vuotuinen pituusksvu (B) Vln kokeell. Koe lnnoitettiin keväällä 1998. Käsittelyt, jotk on merkitty smll kirjimell eivät poikke toisistn Tukeyn testin mukn riskitsoll.5. Käsittelyt esitetty tulukoss 1. Numer of needle ge lsses nd length of needles All tretments inluding K inresed the numer (Fig. 5A). The unfertilized Sots pines hd two needle ge lsses, while pines fertilized with pet sh nd potssium hd three lsses, on ver- estlishment, the verge numer of needle ge lsses hd dropped elow two in ll tretments. Fertiliztion inresed the length of needles needle length three yers fter tretment y 47 % nd tretments with pet sh nd dded potssium y 97 129 %. Six yers fter tretment the effet nt ut only the tretment with pelletized pet sh nd iotite resulted in higher needle length thn the ontrol. nd folir nutrient onentrtions eh tree. Alredy three yers fter fertiliztion, K unfertilized or fertilized only with pet sh (Fig. 6). Six yers fter fertiliztion visully oserved trees fertilized with pet sh nd K. Even though unfertilized trees hd the highest mount of visu- mesurement, the differene etween tretments Folir N onentrtions were high nd in the optimum rnge for Sots pine on petlnds (Prlhti et l. 1971, Reinikinen et l. 1998), nd t the end of the study period even ove the optimum vlues (Fig. 7). Folir P onentrtions were t poor level during the whole study period of 17 yers (1.27 1.29 g kg -1 ), nd there were no
Suo 67(2) 216 59 mm Men tree dimeter (D1.3 ), Men tree volume, dm 3 9 8 7 6 5 4 3 2 1 2 18 16 14 12 1 8 6 4 2 A B F = 6.625 p =.1 PA PA+Ks PA+Bip PA+Bi F = 1.389 p =. PA PA+Ks PA+Bip PA+Bi Figure 4. Men dimeter t rest height (d1.3) (A) nd men volume (B) of living trees t the end of the experiment, when 17 growing sesons were elpsed sine the fertiliztion tretment. Tretments mrked with the sme letters do not differ from eh other ording to Tukey s For tretments, see Tle 1. Kuv 4. Elävien puiden keskiläpimitt (A) j keskitilvuus (B) 17 vuoden kuluttu lnnoituksest. Käsittelyt, jotk on merkitty smll kirjimell, eivät poikke toisistn Tukeyn testin mukn riskitsoll.5. Käsittelyt esitetty tulukoss 1. Numer of needle ge lsses Averge length of the needles, mm 8 6 4 2 4 3 2 1 F 3yr. = 18.95, p =. F 6yr. = 1.83, p =.148 F 17yr. = 1.871, p =.141 A B 3 yers 6 yers 17 yers PA PA+Ks PA+Bip PA+Bi F 3yr. = 21.759, p. =. F 6yr. = 3.427, p =.2 3 yers 6 yers PA PA+Ks PA+Bip PA+ Bi Figure 5. The numer of needle ge lsses (A) nd verge length of urrent yer needles (B) 3, 6 nd 17 yers from the fertilistion tretment. Tretments mrked with the sme letters in the sme study yer do not differ from level. For tretments, see Tle 1 Kuv 5. Neulsvuosikertojen lukumäärä (A) j neulsten keskipituus (B) 3, 6 j 17 vuott lnnoituskäsittelystä. Käsittelyt, jotk ovt smn vuoten merkitty smll kirjimell, eivät poikke toisistn Tukeyn testin mukn riskitsoll.5. Käsittelyt esitetty tulukoss 1. differenes in P onentrtions etween the tretments. Folir K onentrtions were low, men vlues (2.5 3.1 g kg -1 ) eing muh lower thn Fertiliztion y pet sh nd iotite inresed fter fertiliztion. After 17 growing seson the effet of fertiliztion ws moderte (p =.57). Folir B onentrtions deresed in ll tretments during the study period ut were still mg kg -1 ) (Fig. 7). Fertiliztion tretments did not result ws the sme with C, Mn nd Cu onentrtions (results not shown here). Fertilized trees (exept in the PA+Ks tretment) hd higher Mg onentrtions (.99 1.3 g kg -1 ) thn unfertilized trees (.77 g kg -1 ). Fertiliztion lso inresed the mss of needles (Fig. 7). Six nd ten yers fter fertiliztion the needle mss in the trees fertilized with pelletized pet sh nd iotite ws higher thn in the trees left unfertilized or fertilized with pet sh. Ten yers fter fertiliztion lso the other the needle weight. Disussion Generlly, ompred to drined petlnd forests the pet N stores in utwy petlnds re higher, ut those of P mostly equl nd K muh lower (Ferm & Kunisto 1983, Kunisto & Pvilinen 1988, Kunisto & Viinmäki 1991, Hytönen 1995, Aro et l. 1997, Aro & Kunisto 23). In this study the totl mount of N (3,755 kg h 1 ) or-
6 Hytönen et l. % 1 Apperne of the K defiieny symptoms, % 8 6 4 2 3 ers 6 ers 17 ers 3 6 313 p 14 6 11 p 2 17 1 579 p 27 PA PA+Ks PA+Bip PA+Bi toms in the pine needles fter 3, 6 nd 17 yers elpsed sine the fertilistion tretment (% of the ll seedlings). Tretments mrked with the sme letters in the sme study yer do not differ from eh other ording to Tukey s test For tretments, see Tle 1. Kuv 6. Neulsten värin perusteell rvioitujen kliumpuutossymptomien esiintyvyys männyntimill 3, 6 j 17 vuott käsittelystä (% kikist timist). Käsittelyt, jotk on smn vuoten merkitty smll kirjimell eivät poikke toisistn Tukeyn testin mukn riskitsoll.5. Käsittelyt esitetty tulukoss 1. responded well to mounts mesured in the sme lyer t two other utwy petlnds in northern nd estern Finlnd ( Aro et l. 1997, Huotri 211), ut ws lerly higher thn in southern utwy petlnds (Kunisto & Viinmäki 1991, Aro et l. 1997, Aro & Kunisto 23). However, the Pelso pet K (8 kg h -1 ) nd P (99 kg h -1 ) stores in the 1 m lyer were extremely low ompred to results from unfertilized pet in northern nd estern Finlnd (K 2 35 kg h -1, P 15 17 kg h -1, Aro et l. 1997, Huotri 211). In the southern utwy petlnds K nd P stores in the surfe 1-m-thik pet lyer hve vried etween 1 25 nd 7 12 kg h -1, respetively (Kunisto & Viinmäki 1991, Aro et l. 1997, Aro & Kunisto 23). Due to high pet N ut very low P nd K stores t the Pelso utwy petlnd, nutritionl imlne ws extremely severe. Therefore, the Pelso site ws very suitle for testing P nd K fertilizers. However, due to extreme nutritionl onditions the durtion of fertilizer response t the test site ould e shorter thn in petlnd forests generlly. The seedlings grew extremely poorly when left unfertilized. At the end of the study period these trees were the shortest, nd hd the lowest volume. This tretment lso showed the highest tree mortlity (4 %). The unfertilized trees hd lso fewer needle ge lsses nd the length of the needles ws the shortest. Almost ll ontrol hve ontt with the minerl soil nd thus they did not get minerl nutrients from there. Pet sh did not inrese folir nutrient onentrtions of seedlings nd the K onentrtion ws very low (2.5 3.5 g kg -1 ). Also in severl other studies pet sh hs not een shown to inrese folir K onentrtion of Sots pines growing on petlnds (Isskinen et l. 1994, Silfvererg & Isskinen 1987) or downy irhes on utwy petlnds (Huotri et l. 211). Moilnen et l. (212) even reported tht espeilly in fertilized, nitrogen-rih sites pet sh seemed to hve even pet sh did not meliorte the lk of K. Also on fforested orgni frmlnd pet sh proved to e inrese folir K onentrtions two or eight yers following pplition (Hytönen 23). The ute 6 to lmost 1 % of trees fertilized with pet sh sh did not inrese Sots pine folir P onentrtions in this study or in the study y Silfvererg & Isskinen (1987), in some other studies minly smll inreses hve een reported espeilly t high pplition rtes (e.g. Isskinen et l. 1994, Mndre et l. 21) lsting even 2 3 yers fter fertiliztion (Moilnen et l. 212). In this study, 17 yers fter the tretments lmost one third of seedlings fertilized with pet sh hd died. Pet sh inresed the height nd men volume of seedlings y 83 % nd 188 % respetively ompred to unfertilized ontrol seedlings. Erlier Isskinen et l. (1994) mesured 21 % height inrese during period of 13 yers in nine experiments with pet sh (4-1 t h -1 ) estlished on petlnds. Similrly, Moilnen et l. (212) reported 35 6 % greter volume growth for the pet sh fertilized trees ompred to unfertilized trees fter ten or more yers. In their study pet sh hd long-lsting effet on the growth of Sots pine (3 yers fter pplition).
Suo 67(2) 216 61 N, g kg -1 24 22 2 18 16 14 12 1 8 6 4 2 N F 6yr. =.61, p =.663; F 1yr. = 2.599, p =.9; F 17yr. = = 4.928, p =.27 P, g kg -1 1.8 1.6 1.4 1.2 1..8.6.4.2. P F 6yr. =.371, p =.825; F 1yr. =.6, p =.67; F 17 yr. =.76, p =.58 6 yers 1 yers 17 yers 5 4 K F 6yr. = 3.89, p =.32; F 1yr. = 3.19, p =.57; F 17yr. =.61, p =.667 2 15 B F 6yr. = 2.4, p =.18; F 1yr. = 1.539, p =.253; F 17yr. =.47, p =.757 K, g kg- 1 3 2 1 mg kg -1 B, 1 5 PA PA+KPs PA+Bip PA+Bi PA PA+Ks PA+Bip PA+Bi Dry mss, g 1 needles -1 2. 1.5 1..5. F 6yr. = 5.833, p =.7; F 1yr. = 6.766, p =.6 PA PA+KPs PA+Bip PA+Bi Figure 7. Folir N, P, K, nd B onentrtions fter 6, 1 nd 17 yers, nd dry mss of 1 needles 6 nd 1 yers fter tretments. Tretments mrked with missing or sme letters in the sme study yer do not differ from eh other ording For tretments, see Tle 1. Kuv 7. Neulsten N-, P-, K- j B-pitoisuudet 6, 1 j 17 vuott lnnoituksen jälkeen j sdn neulsen mss 6 j 1 vuott käsittelystä. Keskirvot, jotk eivät poikke toisistn tilstollisesti merkitsevästi smn vuonn, on merkitty eri kirjimin. Käsittelyt esitetty tulukoss 1. Comining iotite nd pet sh inresed fter fertiliztion, ut not fter ten or more yers. Also, in erlier studies dding K to pet sh did l. 211) or Sots pine folir K onentrtions fter 13 (Isskinen et l. 1994) or 27 yers from pplition (Moilnen et l. 212). However, in petlnd forests in generl the potssium dose ienies for 15 2 yers when K is pplied s potssium hloride nd onsiderly longer when pplied s iotite (Moilnen et l. 25). However, in this study K onentrtion ws elow the osions proly due to the extremely low originl K ontent of the growing sustrte. Due to etter growth, slightly higher mount of nee- lrger needle mss, fertilized pines hd tken nd umulted muh more K thn unfertilized trees. When potssium hloride or iotite ws dded to pet sh not single seedling died during the study period. Addition of K to pet sh inresed height growth of seedlings y 127 171 %. The height growth of seedlings ws similr ross ll tretments where K ws dded (potssium hloride or iotite). However, it seemed tht the effet of potssium slt ws smller, even though the differene etween the tretments ws not 324 428 % higher thn tht of unfertilized trees nd 98 147 % higher thn those fertilized with mere pet sh. Erlier, Isskinen et l. (1994) lso reported tht in fertiliztion of Sots pine dding potssium hloride to pet sh inresed the height growth of trees. Similrly Moilnen et
62 Hytönen et l. l. (212) reported tht omined use of pet sh nd K fertilizer inresed stnd growth more thn the single pplition of either pet sh or K lone. Pet sh pelletized with iotite ws ompred with un-grnulted pet sh nd iotite. There tretments. Even iotite, onsidered to e slowsolule potssium fertilizer, gve similr results s fst-solule potssium hloride. Pelletizing sh nd iotite did not derese growth of seedlings ompred to un-pelletized mterils nd growth ws even slightly higher with pelletized fertilizer. However, this differene ws not sttistilly inrese the usility of pet sh. In onlusion, the study showed tht singletree fertiliztion experiments n e ost effetive nd give similr results s experiments using lrge plots. Single-tree plots hve lso previously een suessfully used to sreen fertiliztion tretments (e.g. Binkley et l. 1995, Srslmi & Tmminen 25, Littke et l. 214). However, growth results otined from single-tree plots nnot e diretly onverted to stnd level. Pet sh is primrily P fertilizer nd due to its low K ontent its use in fertiliztion of petlnd forests is limited. On petlnds, pet sh fertiliztion resulted in lerly smller generl growth response y trees ompred to trees fertilized with wood sh or ommeril PK-fertilizer (Isskinen et l. 1994, Moilnen & Isskinen 23). Isskinen et l. (1994) reommended using pet found. However, dding K to pet sh would mke good fertilizer for petlnd forests. For exmple, Moilnen et l. (212) reported tht pet sh with dded K fertilizer inresed stnd volume growth t similr rte s PK-fertilizer nd they oth hd long-lsting effet. Aording to this study, pelletized pet sh nd slow-solule potssium fertilizer (iotite) gve results equivlent to those otined with pet sh nd potssium hloride. Nowdys pure pet sh is not s ommon residue of power plnts s in previously (Moilnen et l. 212), sine pet often urnt with wood. Thus, the mixed pet nd wood shes nowdys ontin more K thn pure pet sh, ut still ontin onsiderly less thn pure wood sh. For these lower qulity shes, improvement y dding K would enle reyling of lrge mounts of nutrients into petlnd forests. Aording to the Finnish At on Fertilizer Produts (Asetus lnnoitevlmisteist 211) dding inorgni mterils to grnulted sh to inrese its usility is llowed. Thus, when low-solule ommeril PK fertilizer is not ville, pet sh omined with K (potssium hloride or iotite) would e good lterntive. As suggested y Moilnen et l. (212) suitle dosge for petlnd fertiliztion would e ir 2 4 t h -1 of pet sh nd 2 3 kg h -1 of potssium hloride. The reommended mount of iotite would e just over one tonne per hetre. The grnultion of the produt would not derese the usility of nutrients nd would ensure good spredility. Aknowledgements We would like to thnk Heikki Vesl nd Eero ssistne in the omputing of the results. Referenes Aro, L, Kunisto, S. & Srinen, M. 1997. Suopohjien metsitys. Hnkerportti 1986-1995. (Summry: Afforesttion of pet utwys res. Projet report in 1986-1995). The Finnish Forest Reserh Institute, Reserh ppers 634. 51 p. Aro, L. & Kunisto, S. 23. Jtkolnnoituksen j ksvtustiheyden vikutus nuorten mäntymetsiköiden rvinnetiln sekä puuston j juuriston kehitykseen pksuturpeisell suonpohjll. (Summry: Effet of refertilistion nd growing density on the nutrition, growth nd root development of young Sots pine stnds in pet utwy re with deep pet lyers). Suo 54(2): 49 68. Aronsson, K.A. & Ekelund, G.A. 24. Biologil effets of wood sh pplition to forest nd quti eosystems. Journl of Environmentl Qulity 33: 1595 165. Asetus lnnoitevlmisteist 24/11. 13.9.211 (At on Fertilizer Produts) Binkley, D., Smith, F.W. & Son, Y. 1995. Nutrient supply nd delines in lef re nd prodution in lodgepole pine. Cndin Journl of Forest Reserh 25(4): 621 628.
Suo 67(2) 216 63 Eriksson, J. 1998. Dissolution of hrdened wood shes in forest soils: studies in olumn experiment. Sndinvin Journl of Forest Reserh Suppl. 2: 23 32. Ferm, A. & Kunisto, S. 1983. Luontisesti syntyneiden koivumetsiköiden mnpäällinen lehdetön iomsstuotos entisellä turpeen nosto lueell Kihniön Aitonevll. prodution of nturlly generted irh stnds in pet ut-over re t Aitonev, Kihniö). Foli Forestli 558. 32 p. Hlonen, O., Tulkki, H. & Derome, J. 1983. Nutrient nlysis methods. The Finnish Forest Reserh Institute, Reserh ppers 121. 28 p. Huotri, N. 211. Reyling of wood- nd petsh suessful wy to estlish full plnt over nd dense irh stnd on ut-wy petlnd. At Universittis Ouluensis. Series A, Sientie rerum nturlium A576. 48 p. Huotri, N., Tillmn-Sutel, E., Psnen, J. & Kuin, E. 28. Ash-fertiliztion improves germintion nd erly estlishment of irh (Betul puesens Ehrh.) seedlings on utwy petlnd. Forest Eology nd Mngement 255: 287 2875. Huotri, N., Tillmn-Sutel, E. & Kuin, E. 29. Ground vegettion exeeds tree seedlings in erly iomss prodution nd ron stok on n sh-fertilized ut-wy petlnd. Biomss nd Bioenergy 33(9): 118 1115. Huotri, N., Tillmn-Sutel, E. & Kuin, E. 211. Ground vegettion hs mjor role in element dynmis in n sh-fertilized ut-wy petlnd. Forest Eology nd Mngement 261: 281 288. Huotri, N., Tillmn-Sutel, E., Moilnen, M. & Liho, R. 215. Reyling of sh For the good of the environment? Forest Eology nd Mngement 348: 226 24. Hytönen, J. 1995. Effet of fertilizer tretment on the iomss prodution nd nutrient uptke of short-rottion willow on ut-wy petlnds. Silv Fenni 29(1):21 4. Hytönen, J. 1998. Effet of pet sh fertiliztion on the nutrient sttus nd iomss prodution of short-rottion willow on ut-wy petlnd re. Biomss nd Bioenergy 15(1): 83 92. Hytönen, J. 1998. Puutuhkst j muist jäteineist vlmistetut pelletit ruduskoivun timien rvinnelähteenä. (Summry: Pellets mde of wood sh nd other wstes s nutrient soures for silver irh seedlings). Suo 49(2): 49 63. Hytönen, J. 1999. Tuhkpellettien hjominen mstoss. Metsätieteen ikkuskirj 3/1999: 533 538. Hytönen, J. 23. Effets of wood, pet nd ol sh fertiliztion on Sots pine folir nutrient onentrtions nd growth on fforested former griulturl pet soils. Silv Fenni 37(2): 219 234. Isskinen, J., Moilnen, M. & Silfvererg, K. 1994. Turvetuhkn vikutus männyn ksvuun j rvinnetiln ojitetuill rämeillä. (Resume: Effets of pet-sh fertiliztion on drined pine mires). Metsäntutkimuslitoksen tiedonntoj 499. 22 p. limestone, si slg nd pet sh s liming gents, nd s lium nd mgnesium sour- Agriulturl Soiety of Finlnd 54: 371 383. Juntunen, M-L. 1982. Tuhkn levityksen terveydellisten hittojen rviointi. Metsäntutkimuslitoksen tiedonntoj 62. 17 p. Kunisto, S. & Pvilinen, E. 1988. Nutrient stores in old dringe res nd growth of stnds. (Seloste: Turpeen rvinnevrt vnhoill ojituslueill j puuston ksvu). Communitiones Instituti Forestlis Fennie 145, 39 p. Kunisto, S. & Tukev, J. 1984. Klilnnoituksen trve vosoille perustetuiss riukusteen männiköissä. (Summry: Need for potssium fertiliztion in pole stge pine stnds estlished on ogs). Foli Forestli 585, 4 p. Kunisto, S., Moilnen, M. & Isskinen, J. lnnoittein suomänniköissä. (Summry: Aptite nd phlogopite s phosphorus nd potssium fertilizers in petlnd pine forests). Foli Forestli 81, 3 p. Kunisto, S., Moilnen, M. & Isskinen, J. 1999. Effet of ptite nd phlogopite pplition on the needle nutrient onentrtions of Pinus sylvestris (L.) on drined pine mires. (Tii- vikutus männyn neulsten rvinnepitoi suuksiin ojitetuill rämeillä.) Suo 5(1): 1 15.
64 Hytönen et l. Kunisto, S. & Viinmäki, T. 1991. Lnnoituksen j leppäsekoituksen vikutus mäntytimikon kehitykseen j suonpohjturpeen ominisuuksiin Aitonevll. (Summry: Effet of fertiliztion nd lder (Alnus inn) mixture on the development of young Sots pine (Pinus sylvestris) trees nd the pet properties in pet utover re t Aitonev, southern Finlnd). Suo 42(1): 1 12. Littke, K.M., Hrrison, R.B., Zowski, D. & Briggs D.G. 214. Assessing nitrogen ferti- mentl design. Forest Eology nd Mngement 33: 137 143. Lumme, I. 1988. Erly effets of pet sh on growth nd minerl nutrition of the silver irh (Betul pendul) on mined petlnd. Silv Fenni 22: 99 112. Mndre, M, Pärn, H., Klõšeiko, J., Ingerslev, M., Stupk, I., Kört, M. & Psrnd, K. 21. Use of iofuel shes for fertiliztion of Betul pendul seedlings on nutrient-poor pet soil. Biomss nd Bioenergy 34: 1384 1392. Moilnen, M. 1993. Lnnoituksen vikutus männyn rvinnetiln j ksvuun Pohjois- Pohjnmn j Kinuun ojitetuill soill. (Summry: Effet of fertiliztion on the nutrient sttus nd growth of Sots pine on drined petlnds in northern Ostroothni nd Kinuu). Metsä tieteen ikkuskirj Foli Forestli 82, 37 p. Moilnen, M. 29. Metsätuhkn rvinteet tkisin metsään. Motivn julkisuj 12/29. 4 p. Moilnen, M., Ferm, A. & Isskinen, J. 1987. Ksvihuonekokeit erilisten jäteineiden vikutuksest hieskoivun lkukehitykseen turvelustll. Metsäntutkimuslitoksen tiedon ntoj 281. 36 p. + ppendies. Moilnen, M. & Isskinen, J. 23. Puu- j turvetuhkien vikutus mperään, metsäksvillisuuden lkuinepitoisuuksiin j puuston ksvuun. Metsätehon rportti 162, 91 metsteho/rportti/rportti_162.pdf Moilnen, M., Isskinen, J. & Silfvererg, K. 212. Pet sh s fertilizer on drined mires effets on the growth nd nutritionl sttus of Sots pine. Working ppers of the Finnish Forest Reserh Institute 231. 18 p. Moilnen, M., Pietiläinen, P. & Isskinen, J. 25. Long-term effets of ptite nd iotite on the nutrient sttus nd stnd growth of Sots pine (Pinus sylvestris L.) on drined petlnds. Suo 56(3): 115 128. Moilnen, M., Srinen, M. & Silfvererg, K. 21. Folir nitrogen, phosphorus nd potssium onentrtions of Sots pine in drined mires in Finlnd. Silv Fenni 44(4): 583 61. Moilnen, M., Hytönen, J., Hökkä, H. & Ahtikoski, A. 215. Fertiliztion inresed growth of mngement in drined petlnd in Finlnd. Silv Fenni. 49( 3): id 131. http://dx.doi. org/1.14214/sf.131 Nieminen, M., Piirinen, S. & Moilnen, M. 25. Relese of minerl nutrients nd hevy metls from wood nd pet sh fertilizers: Field studies in Finnish forest soils. Sndinvin Journl of Forest Reserh 2(2): 146 153. Prlhti, K., Reinikinen, A. & Veijlinen, H. 1971. Nutritionl dignosis of Sots pine stnds y needle nd pet nlysis. (Seloste: M- j neulsnlyysi turvemiden männiköiden rvitsemustiln määrityksessä). Communitiones Instituti Forestlis Fennie 74(5): 58 p. Pietiläinen, P., Moilnen, M. & Vesl, H. 25. Nutrient sttus nd growth of Sots pine (Pinus sylvestris L.) on drined petlnds fter potssium fertilistion. Suo 56(3): 11 113. Pitmn, R.M. 26. Wood sh use in forestry review of the environmentl impts. Forestry 79: 563 588. Reinikinen, A., Veijlinen, H. & Nousiinen, H. 1998. Puiden rvinnepuutokset metsänksvttjn rvinneops. The Finnish Forest Reserh Institute, Reserh ppers 688. 44 p. Srel, I. 1991. Wood, rk, pet nd ol shes s liming gents nd soures of lium, mgnesium, potssium nd phopshorus. Annles Agriulture Fennie 3: 375 388. Srslmi, A. & Tmminen, P. 25. Boron, phosphorus nd nitrogen fertiliztion in Norwy sprue stnds suffering from growth disturnes. Silv Fenni 39(3): 351 364. Silfvererg, K. 1996. Nutrient sttus nd development of tree stnds nd vegettion on sh-fertilized drined petlns in Finlnd. The
Suo 67(2) 216 65 Finnish Forest Reserh Institute, Reserh ppers 588. 27 p. Silfvererg, K. & Isskinen, J. 1987. Turpeentuhkn vikutuksist puuston ksvuun j rvinnetiln käytännön lnnoitustyömill. (Summry: Growth nd folir nutrients in pet-sh fertilized stnds). Suo 38(3 4): 53 62. Silfvererg, K. & Isskinen, J. 1987. Tuhkn määrän j ldun vikutus neulsten rvinnepitoisuuksiin j pinoon rämemänniköissä. (Astrt: Nutrient ontents nd weight of Sots pine needles in sh-fertilized petlnd stnds). The Finnish Forest Reserh Institute, Reserh ppers 271. 15 p. Silfvererg, K. & Moilnen, M. 28. Long-term nutrient sttus of PK fertilized Sots pine stnds on drined petlnds in North-Centrl Finlnd.(Tiivistelmä: PK-lnnoituksen vikutus männyn rvinnetiln Pohjois-Pohjnmn ojituslueill). Suo 59(3): 71 88. Silfvererg, K., Huotri, N. & Kokkonen, A.-M. 21. Puu- j turvetuhkn vikutukset ksvillisuuteen j männyn timettumiseen päätehktull turveknkll. Metsätieteen ikkuskirj 4/21: 341 353. Steenri, B.-M., Krlsson, L.G. & Lindqvist, O. 1999. Evlution of the lehing hrter- gglomertion. Biomss nd Bioenergy 16: 119 136. Tklo, S. 1997. Tuhk j jätteet pelleteiksi lieriöpuristimell. In: Nurmi, J., Hytönen, J. & Polet, K. (Eds.). Energipuust puutuhkksi. The Finnish Forest Reserh Institute, Reserh ppers 66: 59 62. Tiivistelmä: Turvetuhk j iotiitti männyn metsityslnnoituksess suonpohjll Puun j turpeen poltoss syntyvien tuhkien rvinnepitoisuuden vihtelu voi oll suurt. Puutuhkn, joss on melko runssti fosfori (P) j kliumi (K), kierrätystä on tutkittu melko intensiivisesti vuosikymmenten jn. Tutkimustulokset osoittvt, että puutuhkn käytöllä suometsissä on moni etuj. Sen on todettu lisäävän puuston ksvu j prntvn rvinnetloutt sekä vähentävän mperän hppmoitumist (esim. Aronsson & Ekelund 24, Pitmn 26, Huotri ym. 215). Useiss turvetlousmiss turvett käytetään voim- j lämpölitoksiss. Suomess turve muodost 5 7 % kokonisenergin kulutuksest. Nykyisin turvett poltetn useimmiten yhdessä puun knss, jolloin syntyy sektuhki. Turvetuhk j sektuhki rvioidn syntyvän Suomess vuosittin 3 4 tonni (Moilnen 29). Sekä puutuhkn että turvetuhkn sisältämien rvinteiden kierrätys on kiinnostv vihtoehto ktopikoille j läjityslueille viennin sijn. Turve tuhk sisältää runssti fosfori j voisi sopi suometsien lnnoitukseen. Toislt lnnoiteominisuuksi heikentää hyvin lhinen kliumpitoisuus. Irtotuhkn levitys metsiin on teknisesti hnkl. Rkeistminen prnt tuhkn levitettävyyttä j rkeistmisen yhteydessä turvetuhkn on lisättävissä hluttuj rvinteit. Tutkimuksen tvoitteen oli selvittää, prntko kliumlisäys turvetuhkn lnnoitusvikutust männyntimien lkukehitykseen suonpohjll. Kliumlähteinä verrttiin nopeliukoist klisuol j hidsliukoist iotiitti. Lisäksi hluttiin selvittää, millinen on turvetuhk-iotiittipelletin lnnoitusvikutus. Vertilun käytettiin lnnoittmtont käsittelyä j pelkkää turvetuhkkäsittelyä (Tulukko 1). Tutkimus tehtiin turvetuotnnost vputuneell suonpohjll Vln Pelsonsuoll. Jäljelle jääneen turvekerroksen keskimääräinen pksuus oli 38 m. Vikk suonpohjn 1 m:n kerroksess oli runssti typpeä (3755 kg h 1 ), olivt fosfori- (P 99 kg h 1 ) j etenkin kliummäärät (K 8 kg h 1 ) lhiset. Siten koelue sopi hyvin kliumlnnoitteiden vikutusten tutkimiseen.
66 Hytönen et l. Koelueelle istutettiin yksivuotiit männyntimi keväällä 1997. Lnnoituskoe perustettiin seurvn keväänä. Lnnoituskäsittelyt olivt 1) lnnoittmton vertilu, 2) turpeen tuhk 3) turpeen tuhk + klisuol, 4) pelletoitu turpeentuhkn j iotiitin seos j 5) irtotuhk j iotiitti. Rvinnemäärä on esitetty tulukoss 1. Koe tehtiin timikohtisesti levittämällä lnnoitett 1,6 m:n säteelle timien ympärille. Koe toistettiin stunnistettujen lohkojen menetelmällä 1 kert, joten kokeess oli yhteensä 5 tint. Timien pituus mitttiin useit kertoj 17-vuotisen seurntjkson ikn. Lisäksi lskettiin khten jnkohtn neulsvuosikertojen määrä j neulsten pituus. Neulsten värin perusteell rvioitiin silmävrisesti kliumin puutosten esiintyminen 3, 6 j 17 vuoden kuluttu lnnoituksest. Tutkimusjkson ikn timi kuoli lnnoittmttomill koeloill j turvetuhk sneill loill. Kuusi vuott kokeen lnnoittmisen jälkeen timi oli kuollut minituill käsittelyillä 22 31 % (kuv 2). Ilmn lnnoitust timet ksvoivt huonosti j elävien puiden keskipituus oli kokeen lopuss 2, m (kuv 3). Turpeen tuhk lisäsi tilstollisesti merkitsevästi timien ksvu j puiden pituus kokeen lopuss oli 3,7 m. Pisimmät timet löytyivät koeloilt, joille oli tuhkn lisäksi nnettu kliumi joko klisuoln ti iotiittin. Kliumlähteiden välillä ei todettu eroj. Turvetuhk-klisuol-käsittelyllä puiden keskipituus kokeen lopuss oli 4,5 m j turvetuhk-iotiittikäsittelyllä puut olivt 5,2 5,4 m pitkiä. Tuhkn j iotiitin rkeistus ei vikuttnut mitttuihin puustotunnuksiin. Puiden keskitilvuus oli turvetuhk-loill kksinkertinen verrttun lnnoittmttomiin loihin (kuv 4). Kun lnnoituksess käytettiin turvetuhkn lisäksi kliumi, timien keskitilvuus oli 4 5 kert lnnoittmttomi suurempi. Lnnoitus lisäsi neulsten vuosikertojen lukumäärää j neulsten pituutt (kuv 5). Kliumin puutoksi esiintyi lnnoittmttomiss timiss j tuhklnnoitetuiss timiss kolme vuott kokeen perustmisen jälkeen (kuv 6). Kuusi vuott lnnoituksen jälkeen rvinnepuutosoireit lkoi esiintyä myös turvetuhkll j kliumill lnnoitetuiss timiss. Neulsten typpipitoisuudet olivt hyvin korkeit, mutt fosfori- j kliumpitoisuudet olivt lle puutostson (kuv 7). Lnnoitus kohotti neulsten kliumpitoisuuksi kuusi vuott lnnoituksen jälkeen, mutt vikutus oli pieni 17 vuoden kuluttu. Tutkimuksen mukn turvetuhkn j iotiitin yhdistelmä on hyvä lnnoite fosforin j kliumin puutoksist kärsiville suonpohjille. Tuloksi voidn yleistää myös sellisille metsäojtetuille soille, joill tvttvt puiden rvinnetlousongelmt ovt smnkltisi kuin suonpohjill. Kosk hidsliukoist kupllist PK-lnnoitett ei ole mrkkinoill, iotiitin lisääminen turvetuhkn mhdollistisi tuhkn perustuvien lnnoitteiden rk-inepohjn ljentmisen. Rk-ineseosten rkeistminen ti pelletoiminen helpott levitystä, eikä näyttäisi vikuttvn puuston ksvurektiot vähentävästi. (Reeived 18.3.216, Aepted 1.8.216)