Artikkelit jotka sisältää sanan 'fertilization'

Monien minerotrofisten avosuo- ja sekatyyppien aluskasvillisuus karuuntuu metsäojituksen seurauksena. Tämä liittyy kasvien ravinteiden saantia säätelevään vaihtokapasiteettiin. Kun ojituksen seurauksena vesitilavuus pienenee ja happamuus kasvaa, kasvupaikalle leviää laji, jonka vaihtokapasiteetti on kosteammalla alustalla viihtyvän lajin vaihtokapasiteettia korkeampi. Suokasviyhteisön vesi- ja ravinnetalous kytkeytyvät näin toisiinsa. Tässä katsauksessa tarkastellaan lyhyesti myös pintaturpeen ravinnevaroja ja ravinteiden kiertoa. Ojituksen aiheuttamasta kosteus- ja ravinnevaihtelun pienentymisestä on seurauksena se, että ojitus korostaa korpisuuden ja rämeisyyden merkitystä kasviyhteisöjen koostumusta määräävinä tekijöinä: korpisuus sisältää kuusivaltaisten kivennäismaiden kasvillisuutta ja rämeisyys vähäravinteisten mäntymetsien kasvillisuutta. Avosuo- ja sekatyypeillä lajiston vaihtuminen eli kasviyhteisön muutos ojituksen seurauksena on yleensä suurempi kuin aidoilla, mätäspintavaltaisilla suotyypeillä. Metsäojituksen jälkeen aidot korpi- ja rämetyypit pitävät aluskasvillisuuden osoittaman ravinteisuustasonsa parhaiten ja sekatyypit sitä paremmin mitä enemmän kasvupaikalla on korpisuus –reunavaikutusta. Avosuo- ja rämesekatyyppien ravinteisuustaso sitä vastoin laskee. Artikkelissa arvioidaan sen aiheuttamia seurauksia ja ongelmia kasvupaikkojen luokittelulle. Työssä kuvataan rämekarhunsammalturvekangas, joka sijoittuu erikoistapauksena varputurvekangas II –tyyppiin. Lopuksi tarkastellaan lannoitusvaikutuksia ja pohditaan kakkostyypin turvekankaiden tulevaa kehitystä. Lannoitukset muuttavat runsastyppisten, mutta vähän kivennäisravinteita sisältävien avosuo- ja sekatyyppilähtöisten turvemaiden kasvuolosuhteita ja kasvillisuutta huomattavasti. Ravinteisuusluokka voi nousta - jatkolannoituksin ja tuhkalannoituksella se on ilmeistä. Avosuo- ja sekatyyppien turvekangaskehitys voi olla hyvin vaihtelevaa ja epävakaata johtuen alkuperäisen suon ravinteisuudesta, turvekerroksesta ja sen rakenteesta, ojitustehokkuudesta, lämpösummasta ja erilaisista lannoituksista. Kun tällaisia ojitusaloja on kuivattu pitkään ja niitä on lannoitettu sekä myöhemmin uudistettu pintaturvekerrosta muokaten, nevaisuudesta tai lettoisuudesta kertovaa II-tyypin leimaa on vaikea tai mahdotonta havaita.

• Hotanen, Luonnonvarakeskus, Joensuu. PL 68, 80101 Joensuu Sähköposti: juha-pekka.hotanen@luke.fi
• Saarinen, Sähköposti: ei.tietoa@nn.oo
• Nousiainen, Sähköposti: ei.tietoa@nn.oo

In the next few decades, industrial peat extraction will cease gradually over more than 80,000 hectares of cutaway peatlands in Ireland and alternative land uses will change the landscape of these areas. This study showed that substantial natural regeneration of downy birch (Betula pubescens) can occur on abandoned as well as cutaway peatlands afforested with conifers. Natural seedling birch stands measured in this study had an estimated biomass production of between 3100 and 5800 kg dry matter ha–1 year–1. This corresponded to an annual carbon stock increment estimated at between 1500 and 2900 kg C ha–1. Direct sowing experiments conducted in this study were the first of their kind in Ireland and showed that sowing downy birch and fertilization with P and K could be a possible management option for the after-use of cutaway peatlands. Exposure was the main obstacle to successful germination and artificial shelter led to higher rates of germination and survival of birch seedlings after the first winter. It can be concluded that birch (naturally or artificially established) can be a feature of this future landscape, bringing many attributes: nurse species, biomass, increased woodland cover and biodiversity.

• Renou-Wilson, F. Renou-Wilson, School of Biology and Environmental Science, Agriculture and Food Centre, University College Dublin, Belfield, Dublin 4. Tel: +353 17167725; Fax: +353 17161102; email: Florence.Renou@ucd.ie Sähköposti: ei.tietoa@nn.oo
• Pöllänen, Sähköposti: ei.tietoa@nn.oo
• Byrne, Sähköposti: ei.tietoa@nn.oo
• Wilson, Sähköposti: ei.tietoa@nn.oo
• Farrell, Sähköposti: ei.tietoa@nn.oo

The low availability of usable phosphorus (P), as well as the scarcity of potassium (K), are often limiting tree growth on peatlands. Approximately one third of the 5.5 million ha of peatlands drained for forestry in Finland has been fertilized during the last 50 years. The aim of this study was to determine the long-term effect of PK fertilization on the nutrient status of Scots pine on different site types of drained peatlands. Changes in nutrient concentrations (N, P, K) and dry mass of current needles was used for examining the effect of fertilization. The material included 82 fertilization experimental stands comprising a total of 892 needle samples; 434 from PK-fertilized and 458 from unfertilized control stands. The needles were collected and analyzed between 1980 and 2002. Depending on the experiment, a time period of 1–35 years had elapsed between fertilization and needle sampling. More than half (54%) of the control stands had P concentration below the defi ciency limit 1.3 mg g–1, and correspondingly, 48% had K concentration below 4.0 mg g–1. Fertilization increased considerably the needle dry mass and foliar P and K concentration raised above the deficiency limits. The lower the concentrations of foliar P and K and the higher the concentration of N were in control trees, the more pronounced the effect of PK fertilization was. Compared to control, the needle P concentration was still noticeably higher on the fertilized stands after 21–35 years of the fertilization. However, K concentration had decreased and was at the same level as in the control trees. The effect of fertilization was strongest on sites which had been treeless or sparsely forested before drainage and which had severe nutrient shortages or imbalances. The response to fertilization was very similar regardless of the temperature sum of the year the needles first appeared. The results of this study show that the P status of Scots pine could be improved for over 30 years with single fertilization. On the other hand, ensuring the K status will require 1–2 refertilization treatments during the rotation period.

• Silfverberg, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo

We studied the natural regeneration of a cut-over peat bog in the Sumava Mountains, Czech Republic. The spontaneous revegetation by vascular plants has been limited by extreme abiotic conditions left after peat mining. Only 1-2% of the total area was recolonized by Sphagnum mosses. This was mainly because drainage channels are still drying out the bog. Only plants tolerant to water stress such as Juncus effusus, Molinia caerulea, Eriophorum angustifolium and E. vaginatum were able to establish there. A key species colonizing bare surface is a clonal plant E. angustifolium. It forms circular polycormons of densely aggregated ramets. As in other radially spreading phalanx plants, the oldest (central) part of the system gradually dies, previously connected ramets become separated, and ring polycormon becomes open to recolonization by other plant species. We analyzed the relationships between species richness of the ring and their size, percentage litter cover, distance to seed sources, and soil fertility. The number of plant species was higher in the middle of the polycormons. The soil was more fertile in the central area than in the surroundings. We conclude that the restoration of highly disturbed habitats can be facilitated by clonal behavior of pioneer populations.

• Lanta, Faculty of Bilogical Sciences, University of South bohemia, Branisovska 31, CZ-370 05 Ceske Budejovice, CzechRebuplic Sähköposti: ei.tietoa@nn.oo
• Doležal, Sähköposti: ei.tietoa@nn.oo
• Samata, Sähköposti: ei.tietoa@nn.oo

The nutritional status of Scots pine (Pinus sylvestris L.) stands growing on a nitrogen-rich, drained pine mire in western Finland was studied after refertilization using needle analysis and the response of stand volume growth. The main aim was to find out if K-refertilization alone could maintain or increase the volume growth without causing a nutrient imbalance between K and P. The initial fertilization was carried out in 1961 - 62 using PK fertilizer and refertilized in 1976 and 1989 with different combinations of nitrogen (N), phosphorus (P), potassium (K) and boron (B). Needle samples were taken and the tree stands were measured in 1996 and 2001. Peat samples were taken in 2002. According to the needle analysis results, the concentration of P was above the deficiency level in all the treatments in 1995 and 2000. There was a clear shortage of K in the needles collected from the control treatment, but the concentration of K was still adequate 12 years after the latest K refertilization. The volume growth of the stands clearly responded to the 1976 refertilization with K alone, which was probably due to the fact that trees had been suffering from K deficiency before the first refertilization and 14-15 years thereafter. After the second refertilization, the combination of K and P increased the annual volume growth more than refertilization with K alone. This indicates that about 25 years after the initial fertilization, there was already some shortage of P. The highest stand volume was associated with the combined K (1976) and PK (1989) refertilization treatment. Refertilization with N did not increase stand volumes during the study period.

• Rautjärvi, The Finnish Forest Research Institute, Joensuu Research Centre, Box 68, FIN-80101 Joensuu Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo
• Tolonen, Sähköposti: ei.tietoa@nn.oo

Wood production capacity on drained peatlands depends on the site type and temperature sum. Site type is closely related to the peat total nitrogen concentration. This study aims at clarifying the effect of peat nitrogen, fertilization and refertilization on the foliar nitrogen concentration of Scots pine in different temperature sum conditions (850, 950 and 1080 d.d.) on peatland sites with a wide peat nitrogen gradient (0.79- 2.80% in the 0-10 cm layer). In the coldest region, regardless of the peat total nitrogen concentrations in the 0-10 cm surface peat layer and PK- fertilization or PK-refertilization (37 and 26 years earlier respectively), the needle nitrogen concentrations were mostly below the severe deficiency limit (N = 1.2%) and also the arginine concentrations revealed a nitrogen shortage (<0.5 mg g-1). In the middle region the mean nitrogen concentrations in the needles were clearly higher and in the PK- fertilization and PK-refertilizations (32 and 22 years earlier respectively) surpassed the slight nitrogen deficiency limit (N = 1.3%). Also the arginine concentrations surpassed the deficiency limit (0.5 mg g-1 ) in both fertilization treatments although the mean arginine concentrations were near or under the deficiency limit. In the warmest region 25-26 years after the spot fertilization the mean nitrogen concentration was 1.84% and the arginine concentration was 3.04 mg g-1 revealing a surplus of nitrogen caused by phosphorus and potassium deficiencies. The PK-fertilization given 10 years later decreased the nitrogen concentration to 1.56% and the arginine concentration to 0.58 mg g-1. In the more favourable conditions the nitrogen and arginine in the needles increased when the nitrogen in the peat increased. In conclusion, tree growth in the middle and the warmest temperature sum region would respond to PK-refertilisation above a certain total peat nitrogen level but in the coldest temperature sum region tree growth would not respond to PK-refertilization in any of the studied peat total nitrogen conditions because of nitrogen deficiency.

• Pietiläinen, The Finnish Forest Research Institute, Muhos Research Station, Kirkkosaarentie 7, FIN-91500 Muhos, Finland Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo

The effects of pellets made of wood ash and of ash mixed with other wastes (composted mink dung, composted municipal sewage sludge, dung from stomachs of slaughtered animals) on the growth and nutrition of silver birch (Betula pendula Roth.) seedlings was studied in a greenhouse experiment. Seedlings were grown in peat soil originating from a drained dwarf-shrub pine bog, peat soil from an afforested field, and in mineral soil. The pellets were applied in varying doses (0, 6, 12, 24, 48 t ha-1). When applied at the rate of 24 t ha-1, also the effect of pelletizing was studied. The pellets promoted the growth of the seedlings depending on the waste used, growing medium, and the application amount. The pellets containing the highest amounts of nitrogen had the effect of increasing growth most of all. As compared with the unpelletized-waste treatment, the use of pelletized waste material decreased seedling growth. This was probably due to the reduced solubility of the nutrients contained by the waste material when presented in pelletized form. Pellets increased the foliar nutrient concentrations of many elements depending on the waste used, the growing medium, and the application amount.

• Hytönen, The Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland Sähköposti: ei.tietoa@nn.oo

The profitability of wood ash-fertilizing (5-16 t ha-1) of four drained peatland Scots pine stands in central Finland was investigated. The profitability of forest drainage alone and forest drainage plus ash-fertilization was compared. After 44-56 years, the wood ash-fertilization had increased mean productivity by 3.1-12.1 m3 ha-1 a-1. Using an interest rate of 3 % and without subsidies, the net present value of the stands was 2500-20300 FIM ha-1 higher as a result of the ash-fertilization than the value given by forest drainage alone. The real internal rate of return due to ash-fertilization without subsidies was 3.7-9.3 %. The interest rate, the fertilization dose and related costs, and the stumpage prices affected profitability. The state forest improvement subsidies further increased the profitablity of ash-fertilization. Key words: forest fertilization, internal rate of return, net present value, Scots pine, stem volume, wood ash

• Lauhanen, The Finnish Forest Research Institute, Kannus Research Station, FIN-69100 Kannus, Finland Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo
• Silfverberg, Sähköposti: ei.tietoa@nn.oo
• Takamaa, Sähköposti: ei.tietoa@nn.oo
• Issakainen, Sähköposti: ei.tietoa@nn.oo

The relationship between electrical conductivity (EC) of press-water extract and water content (WC) of peat growth medium at desorption was studied. A simple time-domain reflectometer (TDR), traditional laboratory conductivity meter and gravimetric weighing were used to measure EC and WC. The relationship between EC values measured with a laboratory conductivity meter from press-water extract and those measured with TDR directly from peat medium was curvilinear. The relationship between WC of peat measured with TDR and that determined gravimetrically, although nearly linear, was slightly sigmoidal. Empirical curve between EC values and WC values measured with TDR was close to the theoretical curve, which was calculated on the basis of increase in ion concentration at desorption. Transformed EC values of press-water extract were higher than the theoretically calculated values. For comparison of EC values measured from press-water extracts in various water contents, transforming coefficients were derived. Key words: nutrient monitoring, fertilization, TDR

• Rikala, The Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland Sähköposti: ei.tietoa@nn.oo
• Heiskanen, Sähköposti: ei.tietoa@nn.oo

Liming (with applications of 1 000 to 8 000 kg ha1) had no long-term (1929-1985) effect on the growth of Scots pine on drained oligotrophic peatlands. Liming plus NPK fertilization had a variable effect on the growth of the stands. The same treatment could result in a very different response in different experimental areas. Both liming alone and liming plus NPK fertilization increased the calcium, magnesium and nitrogen contents of peat and decreased the C/N ratio and acidity. Liming plus fertilization decreased needle boron and manganese and increased calcium and nitrogen concentrations. The results of peat and needle analysis indicated that the changes in nitrogen availability to trees caused by liming have not been sufficient enough to affect tree growth. It was also concluded that boron deficiency was the main reason for the lowered yield. Key words: fertilization, needle nutrients, peat nutrients, Pinus sylvestris, tree growth

• Nieminen, The Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland Sähköposti: ei.tietoa@nn.oo
• Pätilä, Sähköposti: ei.tietoa@nn.oo

The effects of N, P and K fertilizer application rates on the biomass production, soil properties and foliar nutrient status were studied in willow plantations (Salix x dasyclados, Salix 'Aquatica') established on cut-away peatland areas at Haapavesi (64 06'N, 25 36'E and Ruukki (64'27'N, 25 26'E). When the amount of one of the nutrients in NPK-fertilization was changed (N 0-200 kg/ha, P 0-60 kg/ha, K 0-80 kg/ha) the others remained unchanged (N 100, P 30, K 40 kg/ha). Three field experiments were made. Increasing phosphorus and potassium application rates increased the concentrations of corresponding soil extractable nutrients. There was a positive correlation between the fertilizer application rate and the concentrations of foliar nitrogen, phosphorus and potassium. During the first growing season, the effect of nitrogen fertilization on biomass production was modest, but during the second growing season the yield of willows increased the most when fertilized with 100-150 kg N/ha. Although phosphorus fertilization increased yields, already the smallest amounts (15 kg/ha) resulted in biomass yields as high when applying the largest phosphorus fertilizer amounts (60 kg/ha). Potassium fertilization did not increase biomass production in any of the experiments. The highest total biomass yields after three growing seasons were 28-30 t/ha. Their compositions were as follows: 44% wood, 18% bark, 17% foliage, 16% roots, and 5% stumpwood. Key words: biomass production, cut-away peatland, fertilization, energy forestry, Salix

• Hytönen, The Finnish Forest Research Institute, Kannus Research Station, Box 44, FIN-69J 01 Kannus, Finland Sähköposti: ei.tietoa@nn.oo

Biosludge from a biological waste-water treatment plant was tested in a greenhouse experiment on three substrates at 7 levels (0-240 m3/ha). The growth of birch seedlings was best on nitrogen poor substrate collected from a Vaccinium vitis-idaea (VT) forest site. NPK-fertilization was superior to sludge treatments on poor peat substrate. Biosludge increased the foliar nitrogen content on all three soils. Nutritional value of coal ash was tested at 17 levels (0.4-160 t/ha) on mineral soil from an afforested field. Low application levels of coal ash (400-1600 kg/ha) increased the growth of the birch seedlings more than other applications. However, even extremely high coal ash amounts (up to 160 t/ha) were not lethal for birch seedlings. Coal ash increased foliar boron contents two to three fold and with applications higher than 20 t/ha increase was five to seven fold. Birches planted in 1978 on a coal ash landfilling area showed good survival and growth, despite toxic boron contents and visual disturbances in the leaves. Key words: Boron toxicity, fertilization, peat substrate, recycling

• Veijalainen, The Finnish Forest Research Institute, Box 18, FIN-01301 Vantaa Sähköposti: ei.tietoa@nn.oo
• Silfverberg, Sähköposti: ei.tietoa@nn.oo
• Hytönen, Sähköposti: ei.tietoa@nn.oo

Perhaps the most important function of the fine root system of forest trees is in the uptake of water and mineral nutrients. To perform this function adequately, the root system must be extensive and active enough to meet the needs of the canopy. Literature indicates that fine root production is substantial and that the seasonal pattern of fine root production is different from that of foliage production. Carbon incorporation into the soil in the form of dead roots is an important pathway in the total carbon flow through forest ecosystems. Root growth is sensitive to various climatic factors which are often imposed or strengthened by human activities. Factors that lead to growth suspension may or may not be the same as those that result in root shedding or senescence. The use of minirhizo-trons to study fine root dynamics means that ecologists are no longer justified in claiming that below-ground production is impossible to quantify in forest ecosystems. Keywords: Carbon budget, fine root production, liming, fertilization, minirhizotron, mycorrhiza, root tip, soil temperature, soil water

• Persson, Department of Ecology and Environmental Research, Swedish University of Agricultural Sciences, Box 7072, S-750 07 Uppsala, Sweden Sähköposti: ei.tietoa@nn.oo

The authors visited Estonia and Latvia on 20-25.8.1990 in order to get acquainted with peatland forestry research and methods for increasing tree growth on cultivated peatlands, especially by using fertilization. The paper describes peatland forestry in general, paying special attention to the activities in the field of fertilization research on Estonian and Latvian peatlands. Keywords: Drainage, fertilization, peatland forestry

• Kaunisto, The Finnish Forest Research Institute, Parkano ResearchStation, SF-39700 Parkano, Finland. Sähköposti: ei.tietoa@nn.oo
• Ferm, Sähköposti: ei.tietoa@nn.oo
• Kokkonen, Sähköposti: ei.tietoa@nn.oo

The study was made in four experimental fields on drained peatland in western Finland (63-66°N). One of the experiments was laid out in 1972; the others in 1978-1979. Treatments included different kinds of wood ash and PK-fertilizer, an ash-imitating mixture and apatite+biotite. Needle analyses and growth measurements were carried out in 1983— 1986. The concentrations of Mg and Mn generally decreased after fertilization. A rise in the foliar P, foliar K and foliar weight correlated with the growth response. Best growth increment was achieved with the ash-imitating mixture and PK-fertilizer, while apatite+biotite did not increase growth. In the first years after fertilization, growth on the ash plots was weaker, but later stronger or equal to growth on PK- and ash-imitating plots. The correlation between initial tree height and post-fertilization growth was similar on the different treatments. The poor growth increment on some ash treatments was probably due to the insufficient amount of nutrients in the ashes used. Key words: Ash fertilization, Finland, growth, needle analysis, peat, Scots pine

• Silfverberg, The Finnish Forest Research Institute, P.O. Box 18, SF-0I301 Vantaa, Finland Sähköposti: ei.tietoa@nn.oo

Carbon dioxide production increased to 2-3 fold from the peat of an oligotrophic sedge pine mire (VSR) after draining had lowered the water table to a depth c, 0.5 m. At two other sites, a mesotrophic sedge pine mire (RhSR) and a spruce swamp (MK), both the fall in the groundwater table and the increase in C02 production were smaller. At the VSR site, the fast-dissolving PK fertilizer and urea each caused a rapid increase while the slow-dissolving PK fertilizer a slow increase in soil respiration. The greatest, steady increase was achieved by treatment with wood ash. At RhSR and MK sites, the use of fertilizers generally led to a decline in soil respiration for 1-2 years, after which the initial level was normally regained. According to a simulation of the C02 production after drainage, the annual decomposition of peat was calculated to be c. 1 000 g (organic matter) m-2 in the VSR site. On the basis of this decomposition rate, the annual amount of nitrogen mineralizated was estimated to be c. 100 kg ha-1 and that of phosphorus c. 5 kg ha-1. Peat contains only a small amount of potassium, and the decomposition of old peat layers increases the amount of soluble potassium in peat very little. Keywords: Carbon balance, drainage, fertilization, nutrient mineralization, peat decomposition

• Silvola, Department of Biology, University of Joensuu, P.O. Box 111, SF-80101 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo

Runoff from 16 artificial minibasins was sampled after fertilizer application before snowmelt in March and after it in May. Extremely high concentrations of phosphorus, potassium and ammonium were observed during the snowmelt period in April. Key words: fertilization, leaching, peatland, phosphorus

• Ahti, Finnish Forest Research Institute, Department of Peatland Forestry, P.O. Box 18,01301 Vantaa, Finland Sähköposti: ei.tietoa@nn.oo
• Paarlahti, Sähköposti: ei.tietoa@nn.oo

Generally in peat soils but especially in the old forest drainage areas the amount of potassium is low compared with that of nitrogen (ab. 1:100) and phosphorus (ab. 1:4). However, the amount of potassium fixed in tree biomass is about four times the amount of phosphorus. When estimating the future sufficiency of potassium for wood production in old drainage areas after one rotation (drainage 75 years earlier), it seems that on nitrogen-rich deep-peat pine mires potassium stores become exhausted during the second rotation after drainage if potassium is not applied. Key words: Fertilization, peat nutrient stores, potassium, transformed mires

• Kaunisto, The Finnish Forest Research Institute, Parkano Research Station, SF-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo

This study included growth and needle analysis in ash-fertilized spruce and pine stands near Oulu (65 °N, 26 °E). Most of these stands, totalling 770 measured trees, were on peat and fertilized in wintertime 1980 and 1981 as practical work with 40 m3/ha. By 1985 there was a clear increment of growth, especially in spruce stands, probably due to the great amount of phosphorus (375 kg/ha) applied. Keywords: peatland forestry, tree growth, ash-fertilization, phosphorus.

• Silfverberg, Department of Peatland Forestry, The Finnish Forest Research Institu­te, Unioninkatu 40 A, 00170 Helsinki, Finland Sähköposti: ei.tietoa@nn.oo
• Issakainen, Sähköposti: ei.tietoa@nn.oo

The short-term effects of wood ash, PK and NPK fertilizers on total N and P contents of various mosses at an old drainage area in eastern Finland are studied. Total N contents increased after NPK treatment and total P contents increased after treatments that contained phosphorus (NPK, PK, wood ash). N contents of some mosses also increased after treatments which did not contain any nitrogen (PK and wood ash). On these plots drainage and obviously the fertilizer treatment fastened the decomposition rate of the peat and at the same time the mobilization of the nutrients. On the control plots (no fertilization) the N contents of the mosses did not differ statistically between the years in either of the study sites. The P contents of some mosses decreased on the control plots of the spruce swamp. One reason for this was apparently the level of the ground water, which did not lower so much in the spruce swamp than in the pine mire, and so the mobilization of the nutrients remained smaller. The observed nutrient contents of the peat mosses were much smaller than those of the forest mosses and the nutrient contents were also smaller at pine mire than at spruce swamp. Keywords: bryophytes, fertilization, drained peatlands, nitrogen, phosphorus.

• Jäppinen, University of Joensuu. Department of Biology. P.O. Box 111, SF-80101 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo

The short-terms effects of wood ash and NPK fertilizer on the population of Enchytraeidae worms in a drained spruce swamp and pine bog were studied. Both NPK fertilizer (300 kg/ha) and ash (3000 kg/ha) treatments reduced worm numbers at both sites, but the effects were slight compared to seasonal fluctuations. Temporal fluctuations in worm numbers were relatively smaller at the pine bog than at the spruce swamp. NPK fertilizer temporarily changed the relative vertical distribution while tha ash treatment did not. The effects upon worm biomass and respiration rate were similar as those for worm numbers . Key words: Enchytraeidae, NPK fertilization, ash fertilization, drained peatlands

• Hotanen, The Finnish Forest Research Institute, Joensuu Research Station, Yliopistonkatu 7, SF-80100 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo