Suo - Mires and peat vol. 32 no. 1 | 1981

Chemical analyses of anaerobic ombrotrophic Sphagnum peats are presented from four southern Finnish raised bogs. Some characteristics of the study sites and samples are outlined in Table 1. Ranking of the elemental concentrations in Table 2 indicates that among the "trace metals", iron (380 ppm = 0.38 mg/g of dry peat) shows a greater mean concentration in deep ombrotrophic peat layers than the "macronutrients"" phosphorus (160 ppm) and potassium (100 ppm). The lowest averages were found for zinc (8.5 ppm), lead (6.0 ppm), manganese (5.7 ppm) and copper (1.3 ppm). Estimates of long-term accumulation rates of elements in peat (Table 2) are based on volume samples from radiocarbon or pollen-dated profiles (cf. Tolonen 1971, 1977). The average rate of nitrogen accumulation (3.6 kg ha-1 yr-1) appears to be somewhat lower than the corresponding values from Denmark (Jörgensen 1927), Sweden (Mattson & Koutler-Andersson 1955) and Germany (Aletsee 1967). A tentative comparison to watershed studies (Verry 1975, Kauppi 1979) suggests that roughly equal amounts of phosphorus are accumulated by ombrotrophic peat and lost by runoff waters, while in the case of nitrogen the retention by peat is relatively greater. The mean rate of past peat accumulation in the study material (50 g m-2 yr-1, cf. Table 1) is approximately 1/4 of the current mean annual production of Sphagnum fuscum (195 g m-2 yr-1, cf. Pakarinen 1978a) in the same area. A similar comparison of the past accumulation rates of chemical elements (Table 2) with the current retention (consumption) rates by the living moss layer (Pakarinen 1978a,b) gives the following order of elements (peat/moss % ratio in parentheses): N(26.4) > Mg(16.7) > Fe(14.5) > Ca(14.4) > P(11.9) > Zn(8.1) > Pb(7.2) > Cu(5.0) > Mn(0.8) > K(0.6). This comparison suggests that manganese and potassium are to a great extent depleted from peat (by recycling or leaching), while nitrogen is accumulated at about the same relative rate as organic matter. The relatively low percentage values of some elements (Zn, Pb, Cu) probably indicate an increase in atmospheric metal deposition in this century (cf. Aaby & Jacobsen 1979). Detailed budget calculations may not be possible, because no direct information is available on the atmospheric fallout or on the leaching rates 1000 or 2000 years ago. In any case it appears that on annual basis the past accumulation rates of chemical elements (exc. N) in ombrotrophic bogs are quite small. This study has been supported by the Natural Science Research Council, Academy of Finland (macronutrients) and by the Nessling Foundation (trace elements). "

• Pakarinen, Sähköposti: ei.tietoa@nn.oo

Kasvuturpeen ravinteiden analysoimisella on suuri merkitys sekä sen valmistajille että käyttäjille. Ravinneaineiden analysoiminen sinänsä ei ole kovinkaan vaikea tehtävä. Vaikeudet ovat näytteen otossa ja sen esikäsittelyssä analyysiä varten. Tässä työvaiheessa syntyvät suurimmat virhemahdollisuudet ja erot eri analyysimenetelmien vä-lillä. Suurimmat erot aiheutuvat seuraavista seikoista. 1. Eri menetelmissä analyysiin käytettävän turvenäytteen fysikaalinen tila voi poiketa huomattavasti, sillä käytetään ilmakuivaa, kuivattua sekä kostutettua turvetta ja lisäksi näytteet voivat olla joko sellaisenaan tai hienoksi jauhettua. 2. Analyysiin käytetty turvemäärä voi olla joko paino- tai tilavuusyksikköön perustuva. 3. Ravinteiden uutossa käytetään eri uutto-liuoksia, erilaisia uuttoliuosten ja turve-määrän suhteita ja erilaisia uuttoaikoja. Tässä työssä olemme selvittäneet kahden ehkä yleisimmin käytössä olevan menetelmän väliset erot ja vaikutukset pääravin-teiden analysoinnissa. Nämä menetelmät eroavat toisistaan käytetyn uuttoliuoksen (90 ml vettä tai 200 ml 0.5 M ammonium-asetaattia), turvenäytemäärän (40 ml tai 60ml) ja uuttoajan osalta (0.25 h tai 2 h). Osoittautui, että fosfaatin, nitraatin ja natriumin osalta ei menetelmällä ollut vaikutusta. Ammoniumasetaatti oli noin 30 % tehokkaampi kuin vesi uuttoliuoksena kaliumille ja 12—15 kertaa tehokkaampi kalsiumille ja 10 kertaa tehokkaampi magnesiumille. Kokeissa pyrittiin käyttämään turvetta, jonka kosteusprosentti oli 80 %. Silmämääräisessä kostutuksessa päästiin ±1.5 %:n tarkkuuteen. Lyhimmäksi riittävästi uuttavaksi uutto-ajaksi osoittautui 15 min., mutta suosittelemme 30 min. uuttoaikaa, jolloin eliminoituvat ajanottovirheet. Jos jatkuvasti analysoidaan tasalaatuista turvetta, jonka tiheys on vakio, niin tilavuusmitta voidaan korvata painomitalla analyysin tarkkuuden kärsimättä. Tämä nopeuttaa työskentelyä. Suosittelemme, että ammoniumasetaatti-uutosta siirrytään vesiuuttoon, jolloin saavutetaan useita etuja: voidaan hyvin käyttää 30 min. uuttoaikaa, laboratorio rea-genssikustannukset ja jätevesikuormitus pienenevät sekä vältytään ihottumalta, jota ammoniumasetaatti aiheuttaa joillekin henkilöille.

• Tummavuori, Sähköposti: ei.tietoa@nn.oo
• Kaikkonen, Sähköposti: ei.tietoa@nn.oo
• Nyrönen, Sähköposti: ei.tietoa@nn.oo

Dry density of peat — the quantity of dry matter of peat held in unit of volume of peat in situ — depends on several factors, the most important of which are peat type, degree of humification (comp. e.g. Päivänen 1969, Korpijaakko and Rad-forth 1972) and water content (Korpijaakko 1975). Thus knowing of peat types and their degree of humification is not enough for accurate evaluation of the amount of dry matter contained in a peat deposit. Undisturbed samples of known volume from different depths and sites are needed. A piston sampler for this purpose has been developped and applied in the Geological Survey of Finland. The sampler is a modified version of the stationary piston sampler used mainly for palynologieal studies in the Geological Survey. When the coring is performed the piston-cone component of the sampler is kept stationary while the sharpened cylinder is pushed down. Thus the vacume caused by the piston helds peat core on its place while the cylinder cuts it off from the surrounding matter. Because of the strong vacuum effect good samples are obtained also from wett deposit. The diameter of the new sampler is 10 cm (Fig. 1). The cylinder component is devided into three parts. The one in the center is the sample cylinder proper. Its length is 20 cm. The lowest part is 10 cm long. The peat held in this part prevents water from running out from the sample cylinder while the sampler is hoistened. The length of the topmost part of the cylinder is 20 cm. Its function is to hold at the end of the sampling procedure the piston- cone component plus the peat which was disturped while the sampler was pushed down. The cylinder parts are jointed with nuts, which are rotated on to the upper part when the sample is removed. Cylinders are made off stainless steel. Transparent plastic cylinders have been used, too. They are good only in the peat deposits with no sunken logs. The sample cylinder is driven into peat with a rammer. The sampler is hoisted with tongs, which are also used to keep piston-cone component stationary while taking a sample. The equipment is portable. 3—4 men are needed in sampling.

• Korpijaakko, Sähköposti: ei.tietoa@nn.oo

As a result of draining and fertilization, the numbers of a few mushroom species native to moist Sphagnum mosses have decreased while mycorrhizal mushrooms commonly found on mineral soil sites have become frequent. The material was collected in 1975—1976 from 38 experimental plots (comprising a total area of 1,16 ha) at the Alkkia experimental area of Parkano Forest Research Station (Salo 1979). The highest total mushroom yield, 528,3 kg/hectare (fresh weight, Table 1) on an average in 1975—1976, was obtained from the Sphagnum fuscum-Calluna plot treated with NPK fertilizer. High total yields were also obtained from plots fertilized with urea only. The mushroom yield was poorest in the virgin pine bog. Lactarius rufus was the most common mushroom species in this investigation. Its fruit bodies formed 86,8 % of the dry weight of the total mushroom yield. The fruit bodies of Paxillus involutus amounted to 8,3 % of the total mushroom yield. The largest amounts of mushrooms were found on plots fertilized in June 1975 with urea and NPK (Table 3). Other mycorrhizal species amounted to 3,5 % and the fruit bodies of saprophytic mushrooms to 1,4 %. Saprophytic mushrooms were common, for they formed 34,7 % of the fruit bodies collected. The total number of all collected fruit bodies was 27 205 in 1975—1976. During the growing seasons investigated the weather conditions differed greatly especially as regards the precipitation and the mean temperatures in September (Table 4). 1975 was a good mushroom year on peatlands. The production of fruit bodies on mineral soils was very poor in that year. 1976 was exceptional owing to the cold autumn and the dry spell in August. The growing season in 1976 was nearly one month shorter than that in 1975 with the result that the mushroom yield remained poor (Fig. 1.).

• Salo, Sähköposti: ei.tietoa@nn.oo