Suo - Mires and peat 59 (2008)

Neulasanalyysi on vakiintunut menetelmä määrittää puiden ravinnetila ja lannoitustarve. Käytännön metsänhoito-ohjeissa neulasnäytteet suositetaan otettavaksi puiden talvilevon aikana, jolloin puut ovat jäässä ja niiden aineenvaihdunta pysähdyksissä. Ravinneanalyysin tulkinta ja puutostiloja osoittavien pitoisuuksien raja-arvot pohjautuvat niin ikään talvella kerätyistä neulasnäytteistä tehtyihin ravinnemäärityksiin. Tässä tutkimuksessa selvitettiin metsäojitusalueella kasvavien mäntyjen ravinnetilassa syksyn aikana tapahtuvia muutoksia. Keskeinen tavoite oli vastata kysymykseen, voidaanko puiden ravinnetila määrittää luotettavasti jo syys–lokakuussa ennen puiden talvilepoa kerätyistä neulasnäytteistä. Tutkimusaineisto (216 neulasnäytettä) kerättiin kuudesta ojitusaluemänniköstä Keski- ja Pohjois-Suomesta. Aineistoon sisältyi neulasnäytepuita sekä lannoittamattomista että 2–4 vuotta aiemmin PK-lannoitetuista metsiköistä. Ravinnepitoisuuksien erot samoista puista otettujen syys- ja talvinäytteiden välillä olivat suhteellisen vähäiset. Vain lannoitettujen metsiköiden männynneulasten Cu- ja K-pitoisuudet olivat syyskuussa merkitsevästi korkeammat kuin lokakuussa tai seuraavana talvena. Lannoittamattomilla koealoilla neulasten K-pitoisuus oli lähes sama eri ajankohtina. Ca- ja Mn-pitoisuudet puolestaan hiukan kohosivat syyskuun ja sitä seuranneen talvikauden välisenä aikana. Lokakuun ja talvikauden välillä ei puiden ravinnepitoisuuksissa esiintynyt mainittavia eroja. Tulokset osoittavat, että neulasnäytteet voidaan luotettavia ravinneanalyysejä varten kerätä männyistä lokakuun alun ja maaliskuun lopun välisenä aikana.

• Moilanen, Sähköposti: ei.tietoa@nn.oo
• Pietiläinen, 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

The carbon pool of surface layers (up to 500 years old) in 73 boreal mires was investigated in order to assess its significance in the carbon cycle. Peat columns were collected from mires of varying depth, age and degree of natural state in the aapa mire and raised bog regions and coastal mires of southern and central Finland and Russian Karelia. The quantities of carbon sequestered during recent centuries and over the entire lifetimes of the mires were determined using a total of 367 dates (186 14C AMS and 181 conventional dates) and age-depth models derived from bulk density measurements. Particular attention was paid to accumulation over the last 100 and 300 years, as these periods encompass the best estimates of the acrotelm age across the range of sites investigated. The average carbon pool of layers younger than 300 years was determined as 101 ± 8 tonnes ha-1 in the aapa mire region, 115 ± 9 tonnes ha-1 in the raised bog region and 184 ± 20 tonnes ha-1 in coastal mires. Overall, the mean carbon pool of layers younger than 300 years was calculated to be 121 ± 7 tonnes ha-1 (range 44–259 tonnes ha-1) and of layers younger than 100 years 63 ± 4 tonnes ha-1 (range 17–141 tonnes ha-1). The size and dynamics of the carbon pool represented by these surface layers depends upon the mire site type, vegetation and natural state; variations reflect differences in plant communities as well as factors that affect biomass production and decay rates. The high carbon accumulation in surface layers is temporary and mainly related to the development of the mire. The surface layers are still undergoing a rapid carbon cycle. A relatively rapid accumulation and turnover of carbon is taking place in surface layers (<300 years) in the same way as in a growing forest. Therefore, this "pre-peat" in the surface layers of mires should be distinguished as a separate class from the peat underneath. Our results indicate how important it is to understand the carbon accumulation rates of surface layers and the long-term dynamics of mire carbon accumulation in order to set the current flux estimates in perspective.

• Mäkilä, Geological Survey of Finland, P.O. Box, 96, 02151 Espoo, Finland Sähköposti: ei.tietoa@nn.oo
• Goslar, Sähköposti: ei.tietoa@nn.oo

Six field experiments on the use of mineral soil for amelioration of pine-dominated peatland forests were established in the 1920’s and 1930’s on drained mires in southern and central Finland. The treatments consisted of varying amounts of different textured mineral soil added on top of peatland. Soil samples were taken 52–74 years after the mineral soil application in 10 cm layers, up to 40 or 50 cm depth. The samples were analysed for pH, ash content, bulk density and nutrient concentrations. In two of the experiments, foliar samples of Scots pine were analyzed 66 and 77 years after the mineral soil application, and in one experiment, tree growth was measured for the period of 31–60 years after the application. The mineral soil had a long term effect on the physical and chemical properties of the top peat layer. Ash content and bulk density of the peat increased along with increasing application amounts, as did soil total P, K, Ca, Mg, Zn, Fe and B. The changes caused by the mineral soil were mostly restricted to the top 30 cm layer. The higher the soil fine fraction was, so was the increase in peat total P, K, Ca and Mg amounts. The addition of mineral soil increased tree growth and improved nutrient deficiencies (P, K) of Scots pine on one experiment, but decreased the B concentrations near the deficiency level.

• Hytönen, Finnish Forest Research Institute, Kannus Research Unit, P.O. Box 44, FI-69101 Kannus, Finland Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo
• Silfverberg, Sähköposti: ei.tietoa@nn.oo

The aim of is study was to elucidate the bacterial quality of the River Nile water at Cairo region in Egypt. The microorganisms such as heterotrophic bacteria and faecal coliforms were examined. The bacterial isolates were identified using different keys of identification and Biolog metabolic fingerprint system. The results showed the presence of different genera of microorganisms, which were. Alcaligenes, Escherichia, Aeromonas, Pseudomonas, Klebsiella, Enterobacter, Rahnella, Xanthobacter, Streptomyces, Rhodococcus and Arthrobacter. The significance of the results was shortly discussed.

• Rifaat, Microbial Chemistry Department, National Research Centre, Cairo, Egypt Sähköposti: ei.tietoa@nn.oo

The occurrence of the threatened and endangered vascular mire plant species was inventoried in the mire conservation areas in Finland. The survey was based on 246 sample plots (0.5 km × 0.5 km) randomly chosen in the Finnish mire conservation areas planned in 1981 in southern and central Finland. In the inventory, 243 vascular plant species and 2 hybrids were found in bog mires and 249 species and 10 hybrids were found in the southern aapa mires. The majority of the found mire plant species commonly occur on mires in Finland. In this survey, out of 18 threatened primary mire vascular plant species occurring in Finland, only three species (Carex heleonastes L. f., Dactylorhiza incarnata ssp. cruenta (O. F. Mull.) P. D. Sell, D. cruenta (O. F. Mull.) Verm, Orchis cruenta (O. F. Mull.) and Dactylorhiza traunsteineri) (Saut. ex Rchb.) Soo´, Orchis traunsteineri Saut. ex Rchb., Dactylorchis traunsteineri (Saut. ex Rchb.) Verm.; incl. Dactylorhiza curvifolia (F. Nyl.) Czerep.; incl. D russowii (Klinge) Holub and only one so called secondary mire plant species (Carex paniculata L.) were found in the sample plots. The found species occurred only on six mire conservation areas. Compared to the size of the material, the percentage of findings of threatened vascular plant species was remarkably low. It can be concluded that the complementary programs of the mire conservation in Finland have been important to protect the threatened vascular mire plants.

• Hanhela, Oulu University of Applied Sciences, School of Renewable Natural Resources, Metsäkouluntie, FI-90650 Oulu Sähköposti: ei.tietoa@nn.oo