Artikkelit jotka sisältää sanan 'soil'

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

Earthworm populations in reclaimed cutaway peatland soils in central Ireland were sampled 20-30 years after reclamation and establishment of grass-clover leys following industrial peat mining. Nine earthworm species in total were present, with 4-7 species per field in the six fields sampled. Population densities were 130-506 individuals m-2, and biomass ranged from 80 to 279 g m-2. Thus, under favourable conditions reclaimed cutaway peat soils can support earthworm populations comparable in density and biomass to those typical of the most fertile mineral soils. However, species richness tended to be lower than in comparable grasslands on mineral soils, and reclaimed peat appears to be unfavourable for larger deep-burrowing species such as Lumbricus friendi and Lumbricus terrestris.

• Curry, UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland Sähköposti: ei.tietoa@nn.oo
• Schmidt, Sähköposti: ei.tietoa@nn.oo

In Finland, the whole peat layer of a peat production area is used due to the value of the basal peat as energy peat. In this situation the properties of the mineral subsoil below the peat layer are significant when choosing the form of after-use. The geochemical provinces are based on the chemical features of the fine material in till, related to differences found in the bedrock, defined by Geological Survey of Finland. The study of peat production areas (1998-1999, covering 9800 ha) shows that the characteristics of the provinces affects the subsoil sediments. In Lake Ladoga–Bothnian Bay zone subsoils were rich in sulphur and iron. The amount of water soluble sulphur was 3-6 times higher than that in the Granitoid area of Central Finland and the Archaean gneiss areas (calculated as mg kg-1). Below the highest shoreline of the ancient Litorina Sea the average content of the water soluble sulphur in subsoil sediments was ca. seven fold compared to the content found above the highest shoreline, (calculated as mg kg-1). There was also a difference in soil acidity between these areas. Nutrient content varied between sediments, which have the same fine material percentage. In the Lake Ladoga–Bothnian Bay geological zone and in the zones of Svecocarelian schists and gneisses, natural nutrient levels are high when compared to the Granitoid areas.

• Picken, Kekkilä Oyj, P.O. Box 67, 04300 Tuusula, Finland Sähköposti: ei.tietoa@nn.oo

The area of cultivated organic soils, and their distribution in Finland were estimated. The estimation was based on the soil classification data collected by three authorised soil testing laboratories, and the statistics of the arable land area. The data was collected in a five year period (1998-2002). During this period, over 90% of farms received environmental EU supplement and had their soils analysed. Therefore, the reliability of the estimation was now better than it used to be before Finland joined the European Union. In the Finnish soil classification system, organic soils are divided into two classes depending on their organic matter content. The area of organic soils with the organic matter content of ≥40% (m/m) (i.e. peat) was 85000 ha, i.e. 3.8% of the arable area. The area of organic soils with the organic matter content of 20-39.9% (m/m) and often with a mineral subsoil, was 214 000 ha i.e. 9.7% of the arable area. Altogether, the area of these soils was 300 000 ha i.e. 13.6% of the total arable area in Finland.

• Myllys, Maa- ja elintarviketalouden tutkimuskeskus MTT, Maaperä ja ympäristö 31600 Jokioinen Sähköposti: ei.tietoa@nn.oo
• Sinkkonen, Sähköposti: ei.tietoa@nn.oo

Estimates of the area of cultivated acid sulphate soils in Finland range from 50,000 ha to 336,000 ha. In these soils, sulfides are oxidized to sulphuric acid upon aeration, which is promoted by drainage. Agricultural use of these soils requires abundant liming. Acidic drainage waters impact the aquatic life negatively. Early research concentrated on the agricultural utilization of acid sulphate soils while more recently environmental aspects have been emphasized. Controlled drainage, aiming at a high water table, is considered an option for the management of acidity. Owing to evapotranspiration, however, sulfidic layers may be exposed to oxidation every summer in spite of controlled drainage. Successful submerging of sulfidic layers may require pumping of water to the field from outside sources. Abandoning the most acidic sulphate soils and stop draining them would prevent further oxidation of sulfides. This is a sensitive issue, because the farmland is private property. Moreover, it is not exactly known where the most acidic sulphate soils are located and how their abandonment would impact the quality of water in recipient rivers.

• Yli-Halla, MTT Agrifood Research Finland, Environmental research, FIN-31600 Jokioinen, Finland Sähköposti: ei.tietoa@nn.oo

The gaseous plant hormone and air pollutant ethylene (C2H4) has a strong effect on plant physiological processes, such as ripening and senescence, and its removal is often required from contaminated air.This study tested the efficiency of indigenous microor ganisms in horticultural peat-soil to purify C2H4 contaminated air under biofilter condi tions.Peat-soil, acclimated to C2H4 removal, was placed in a biofilter (687 cm3) and subjected to an air flow (73 mL min–1 ) with ~117 ppm C2H4 (ppm, parts per million; equivalent to µL L–1 ).C2H4 was removed to a lowest level of 0.034 ppm after operation of the biofilter for 12 days at 26°C. This corresponded to a C2H4 removal efficiency of >99.9%and a specific C2H4 removal rate of 6.4 µg C2H4 g–1 dry wt soil h–1 (wt, weight). However, this efficient C2H4 removal was only transient (4 days), and during day 16 to 21, the C2H4 removal efficiency decreased to 51%. In contrast to this result, it was previously found that, under comparable biofilter conditions, cultivated ethylene-oxidizing bacteria were able to survive and efficiently remove C2H4 for at least 75 days. Thus, prolonged and efficient purification of highly C2H4 contaminated air by horticultural peat-soil under biofilter conditions apparently depended on bacterial inoculation.

• Elsgaard, Danish Institute of Agricultural Sciences, Department of Crop Physiology and Soil Science, Research Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmark Sähköposti: ei.tietoa@nn.oo

Peat hydraulic conductivity, shear strength, plant composition and runoff at seven peat harvesting sites in Central Finland were measured. A large variation in hydraulic conductivity (10–8–10–6 m s–1 ), peat shear strength (302–413 kPa), and peak runoff (97–898 l s–1 km–2 ) was observed between different harvesting sites. The hydraulic conductivity showed a clear correlation with peat shear strength (r = –0.89), which has not been previously observed. The correlation between hydraulic conductivity and degree of humification was weak (r = 0.60). Soil lowering decreased the hydraulic conductivity and the peat shear strength. These reductions, with reduced drainage depths, increased peak flow and changed runoff generation patterns by increasing the possibility of Horton and saturation excess overland flow.

• Kløve, Jordforsk, Norwegian Centre for Soil and Environmental Research, 1432 Ås, Norway Sähköposti: ei.tietoa@nn.oo

The aim of this work was to determine physical properties of organic soils developed in different sites of the mountain area of Stolowe Mountains National Park, Poland. The profiles with different botanical composition of peat were analysed and classified by types and species of peat. Peat, muck and peat-mud were identified (9 profiles) at chosen locations. Investigation showed that top plateau organic soils were developed on a sandy-loam or sand weathered sandstone base. Organic soils in valleys and slopes were developed on a loamy-silt or clay basement. Peat horizons developed according to different types of sites (mesotrophic and eutrophic, sometimes oligotrophic). Generally, these soils are ombrotrophic, i.e. fed by atmospheric water only. These soils were classified as Fibric Histosols and Terric Histosols. Organic soils within the main regions of the park were over-desiccated, with advancing muck-forming processes being noted.

• Bogacz, Institute of Soil Science and Agricultural Environment Protection, Agricultural University of Wroc aw 50-357 Wroc aw, ul. Grunwaldzka 53, Poland Sähköposti: ei.tietoa@nn.oo

Three Greek soil profiles originating mostly from lacustrine deposits in the district of Filippoi (Northern Greece), were studied. These soils have been formed both from organic and inorganic materials that were deposited by precipitation and developed through the action of aquatic organisms. According to Soil Taxonomy (1992), they are classified as Histosols and belong to the suborder of Saprists. The pH of the soil horizons ranged among soil horizons from 6.2 to 7.8. The total soil nitrogen content ranged between 7.5 and 17.0 g kg–1 and the soil organic matter was between 108.7 and 206.4 g kg–1 . Calcium carbonate was detected into ten horizons and ranged between 1.4 and 27.8%, whilst it was not found in five of the examined soil layers. This is suggested to reflect the presence or absence of aquatic organisms, the shells of which contain CaCO3 and enrich soil by means of weathering. Heavy metals extracted by 4 M HNO3 were in the following order Fe>Mn>Zn>Pb>Ni>Cu>Cd, and their average concentrations were 7190, 294, 72.3, 58.2, 33.3, 17.3 and 5.1 µg g–1 , respectively. The distribution of trace elements greatly differs amongst the examined samples and the range of the pseudototal form of Fe was 1873–18550 µg g–1 , of Mn 54.7–585, of Cu 4.5–40, of Zn 22.0–185, of Pb 20.5–143, of Ni 15–64.7 and Cd 3.3–6.9 µg g–1 . The sequentially extracted by Na2 -EDTA, HNO3 and NaOH were found to be the prevailing metal forms. Iron deficiency symptoms have been observed in certain crops, and manganese deficiency was also detected in some maize crops cultivated in slightly alkaline soils. Furthermore, the plant available boron concentration was determined, as deficiency symptoms were observed in some districts cultivated with sugar beets. The distribution was generally not influenced by soil properties, although a weak relationship between organic carbon and boron was found. Measures such as rational water management, tillage practices, and fertilization could be applied towards minimization of soil degradation, micronutrient disorders and optimization of crop productivity.

• Karyotis, National Agricultural Research Foundation, Institute for Soil Mapping and Classification, 1 Theophrastou Str., 41335 Larissa, Greece Sähköposti: ei.tietoa@nn.oo
• Haroulis, Sähköposti: ei.tietoa@nn.oo
• Vavoulidou, Sähköposti: ei.tietoa@nn.oo
• Papadopoulos, Sähköposti: ei.tietoa@nn.oo

The state of the environment is currently evaluated by indicators of air and water quality. Sustainable land use requires an assessement of soil quality. Soil quality indicators should relate soil processes to management practices. The supply of N and P contributes to crop productivity, but can degrade air and water quality. In this paper, we will present organic soil N and P attributes that can make up soil functions. Nitrate was the only detected mineral N form in organic soil materials with pH (0.01M CaCl2 ) exceeding 4.4. Lowest C/N ratio of cultivated sapric soil materials was 15, showing high nitrate-supplying capability. Total P concentration was between 760 and 1960 mg P kg–1 both in organic and inorganic forms when pH (0.01M CaCl2 ) increased above 4.7, the recommended minimum pH value for cultivated organic soils. Lowest C/P ratio as organic forms was 340 for sapric materials containing less than 22% ash, indicating organic P sequestration capability (C/P > 300). However, the low N/P ratio of 23 (i.e. 340/15) also indicated capability for organic P availability to plants. Since N and P are related to organic matter transformations, the C/N/P/S multiratios of selected organic matter fractions, analyzed as compositional data (computation procedure presented), need further consideration as integrated N and P attributes in combination with pH and climatic indexes, in order to adapt N and P diagnosis and recommendation models to specific organic soil agroecological zones.

• Parent, Centre de Recherche en Géomatique, Laval University, Ste-Foy (Quebec), Canada G1K 7P4 Sähköposti: ei.tietoa@nn.oo
• Viau, Sähköposti: ei.tietoa@nn.oo
• Anctil, Sähköposti: ei.tietoa@nn.oo

The thermal conductivity of low-decomposed Sphagnum peat, used as a growth medium for container seedling production in tree nurseries, and of a sandy mineral soil was studied using the single thermal probe method in the laboratory. The thermal conductivity of the peat was low and decreased from 0.5 to 0.05 W m-1K-1 when the water content decreased from near saturation to air-dry. In comparison, the thermal conductivity of the sandy soil was much higher, decreasing steeply from 1.5 to 0.5 W m-1K-1 with decreasing water content. Results are in accordance with those reported earlier for similar media. The results suggest markedly weaker and more delayed temperature fluctuations in pure peat media compared with media containing mineral soil, which is in agreement with observations made in tree nurseries.

• Heiskanen, Finnish Forest Research Institute, Juntintie 40. FIN-77600 Suonenjoki, Finland Sähköposti: ei.tietoa@nn.oo

The bulk density, organic matter content and soil water-retention characteristics of twenty-one afforested former agricultural peat soils were studied. Soil samples were collected from 5-10 cm, 15-20 cm, 25-30 cm and 35-40 cm soil layers. The studied soils' physical properties differed from those of undrained peatlands and peatlands drained for forestry mainly due to the mixing of mineral soil with the peat during cultivation. In the case of thick peat soils (peat layer >30 cm), the bulk density was at a maximum (0.37 g cm-3) and the organic matter content at a minimum (54%) in the uppermost soil layer. In the case of shallow peat soils (peat layer <30 cm), bulk density increased and organic matter content decreased with increasing soil depth. In thick peat soils, total porosity and water retention at selected matric potentials were at their highest in the lowermost soil layer while in shallow peat soils, the uppermost soil layer possessed the highest total porosity and water retention. Most of the water was retained within the range -100 to -1500 kPa in both soil types. This indicated that small pores were predominant. Air-filled porosity at -10 kPa matric potential (about field capacity) was, on average, 16% in thick peat soils and 17% in shallow peat soils in the uppermost soil layer and decreased with increasing soil depth. The results suggest that the physical properties were generally rather unfavourable for adequate soil aeration and water availability as needed for satisfactory tree growth.

• Wall, Finnish Forest Research Institute, Kannus Research Station, Box 44, FIN-69101 Kannus, Finland Sähköposti: ei.tietoa@nn.oo
• Heiskanen, Sähköposti: ei.tietoa@nn.oo

The effect of mineral soil, applied during the cultivation of fields, on the nutrient amounts of afforested peat fields was studied. 36 afforested peat fields (peat layer>40 cm) from Central Ostrobothnia (western Finland) and North Savo (central Finland) were sampled. Fields were divided into two groups on the basis of mineral soil addition. Volumetric soil samples (0-10, 10-20, 20-30, 30-40 cm layers) were taken and and analyzed for their total and ammonium acetate extractable nutrient concentrations (P, K, Ca, Mg, Mn, Fe, Zn). Kjeldahl nitrogen and boron in H3PO4-H2SO4 were also analyzed. Nutrient amounts in different soil layers were calculated. Mineral soil, mainly silt, had been added on average 230 m3ha-1 in Central Ostrobothnia and 630 m3ha-1 in North Savo. Mineral soil was clearly detectable in the plough layer (0-20 cm) but seldom in the 30-40 cm layer as an increased bulk density and ash content. Mineral soil admixture increased most of the total nutrient amounts, but not nitrogen, calcium and boron. In the amounts of extractable nutrients the effect of mineral soil admixture was smaller. Key words: afforestation, mineral soil, nutrition, peat fields

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

The effect of extraction time on the extraction of P, K, Ca, Mg and the effect of EDTA on the extraction of Mn, Fe and Zn with acid ammonium acetate was studied in 196 soil samples collected from afforested agricultural soils. Extraction time (1 hour or ca. 20 hours) did not significantly affect gravimetrically expressed mean concentrations of K, Ca and Mg in mineral soil samples. In peat samples the mean concentration of Ca and Mg with the shorter extraction time was 73% and 81% respectively of the mean concentration obtained with longer extraction time. The mean concentration of P with the extraction time of 1 hour was about 50% of the mean concentration obtained with the longer extraction time in peat and mineral soil samples. Extraction with acid ammonium acetate/EDTA extracted Fe sevenfold and Zn almost threefold compared with acid ammonium acetate alone. Regression models for converting gravimetric and volumetric nutrient values obtained with methods used in agriculture to gravimetric and volumetric nutrient values obtained with methods used in forestry are presented.

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

Changes in bulk density and water retention during one-year culturing of container seedlings were studied in pure, low-humified Sphagnum peat and in peat-based two-component growth media. In all growth media, the bulk density increased slightly with time. The corresponding decrease in total porosity was negligible (< 1 %-unit for pure peat). At matric potentials < -1 kPa, water retention of growth media tended to increase somewhat with time. On the other hand, shrinkage at desorption decreased during seedling culturing. The results suggest that, from the standpoint of seedling growth, the structure of growth media based on Sphagnum peat does not markedly change or deteriorate during one-year culturing of seedlings. However, in seedling culturing peat growth media containing hydrogel may possess restricted aeration due to excess water retention, while addition of coarse textured materials, such as perlite, to peat can increase aeration. Key words: nursery management, soil physical properties, shrinkage, substrate, water retention

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

In mould soils the concentration of acid ammonium acetate extractable sulphur (SAAAc) was 33 mg/l on average and total sulphur (Stot) was 833 mg/l. Corresponding contents in peat soils were 45 and 1209 mg/l, respectively. Average extractability of sulphur was 4.2 % in mould soils and 3.7 % in peat soils. In both soil types the extractability was highest when pH was lowest. Increasing humus contents decreased slightly the extractability of sulphur. Key words: humus, mould soil, peat soil, pH, extractable and total sulphur L. Urvas, Agricultural Research Centre of Finland, Institute of Soils and Environment, FIN-3J600 Jokioinen, Finland

• Urvas, Agricultural Research Centre of Finland, Institute of Soils and Environment, FIN-3J600 Jokioinen, Finland Sähköposti: ei.tietoa@nn.oo

The content of acid (pH 4.65) ammonium acetate-EDTA (AAAc-EDTA) extractable Cu was in mould soils (9.6 ±5.7 mg/1 soil) about one and a half times that in peat soils (6.6 ± 4.4 mg/1). There was a close positive dependence between extractable Cu and the total Cu in both soil types. The proportion of extractable Cu on the total Cu was in mould soils (wet combustion 40.0 ± 13.3%; dry ashing 40.9 ± 11.3%) somewhat lower than in peat soils (wet combustion 47.4 ± 13.6%; dry ashing 53.4 ± 19.5%). In mould soils the decrease in soil acidity had an increasing effect on both extractable Cu and total Cu contents of soil. In peat soils the extractable Cu and total Cu contents were lowest between pH(H20) values 5.0 and 5.5, and increased with both increasing and decreasing the soil acidity. The extractable Cu and total Cu contents were highest in mould soils of low humus content and in peat soils having humus content between 60 and 70%. Keywords: Humus, mould soil, peat soil, pH, total copper

• Jokinen, Agricultural Research Centre of Finland, Institute of Soils and Environment, FIN-31600 Jokioinen, Finland Sähköposti: ei.tietoa@nn.oo
• Urvas, Sähköposti: ei.tietoa@nn.oo
• Hyvärinen, Sähköposti: ei.tietoa@nn.oo

The contribution of roots to the release of C02 from peat has been examined in both field and laboratory experiments. In the field experiment, columns of peat were isolated from the surrounding peat and the green parts of the plants were continually removed in order to exhaust the living roots contained within the column. The isolated columns released c. 10-20% less C02 than the reference spots where only the growth of the green parts was restrained. C02 production in isolated columns was thereby reduced mostly in mire site types with largest dwarf shrub root biomass. In the greenhouse experiment, C02 release was c. 36% greater from containers containing willow (Salix phylicifolia) roots than from bare peat reference containers. Keywords: Carbon allocation, decomposition, soil respiration

• Silvola, Department of Biology, University of Joensuu, P.O. Box 111, FIN-80J0/ Joensuu, Finland Sähköposti: ei.tietoa@nn.oo
• Jukka, Sähköposti: ei.tietoa@nn.oo
• Ahlholm, Sähköposti: ei.tietoa@nn.oo

Methane fluxes were measured using a static chamber technique on a minerotrophic fen and an ombrotrophic peat bog site located on the Lak-kasuo mire complex in central Finland. Both sites consisted of a virgin area and an area drained in 1961 by ditching. The measurements in 1991 were made biweekly from spring thaw to winter freezing. During this period, the mean CH4 emission from the virgin minerotrophic site and virgin ombrotrophic site was 98 mg m-2 d-1 and 40 mg m-2 d-1 , respectively. The mean emission of CH4 from the drained ombrotrophic site was 18 mg m-2 d-1. The drained minerotrophic site consumed methane during most of the measuring period, the average uptake was 0.13 mg m-2 d-1. Draining had lowered the average water table by 4 cm at the ombrotrophic site and by 20 cm at minerotrophic site. The possible reasons for the different development of the water table and methane fluxes at ombrotrophic and minerotrophic sites after draining are discussed. Keywords: Drainage, methane flux, methane oxidation, nutrient status, peat soil

• Martikainen, Department of Environmental Microbiology, National Public Health Institute, P.O. Box 95, FIN-70701 Kuopio, Finland Sähköposti: ei.tietoa@nn.oo
• Nykänen, Sähköposti: ei.tietoa@nn.oo
• Crill, Sähköposti: ei.tietoa@nn.oo
• Silvola, 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 AAAc-EDTA extractable Zn content in mould soils (2,3±2,0 mg/ l soil) was not dependent on the total Zn content. In peat soils the extractable Zn content (2,0±1,9 mg/l soil) increased with the increase in total Zn content. The proportion of extractable Zn to the total Zn was less than 8% in Zn deficient mould soils but about 40% in Zn sufficient mould soils. In peat soils the corresponding proportions were 30% and 60%. In mould soils the increases in humus content and acidity caused an increase of AAAc-EDTA extractable Zn. In peat soils extractable Zn content increased with increasing humus content up to 65%. The extractable Zn content was highest between pH values 5,0 and 5,5. Keywords: Extractable zinc, humus content, mould soil, peat soil, pH, total zinc

• Urvas, Agricultural Research Centre of Finland, Institute of Soils and Environment, SF-31600 Jokioinen, Finland Sähköposti: ei.tietoa@nn.oo
• Jokinen, Sähköposti: ei.tietoa@nn.oo
• Hyvärinen, Sähköposti: ei.tietoa@nn.oo

Saarinen, J. 1989: Effect of drying temperature on the extractable macro-and micronutrients and pH of different peat types. (Tiivistelmä: Kuivatuslämpötilan vaikutus eri turvelajien uuttuviin pää- ja hivenravinteisiin sekä pH-lukuun. — Suo 40:149-153. Helsinki. ISSN 0039-5471 Increasing the drying temperature from 20 to 105°C decreased extractable iron and lowered pH but increased the extractable phosphorus. Changes in the extractability of other nutrients were negligible. The effect of drying temperature on different peat types was similar. Keywords: Extractable nutrients, peat chemistry, soil analysis

• Saarinen, Agricultural Research Centre of Finland, Institute of Crop and Soil, Soil Science, SF-31600 Jokioinen, Finland Sähköposti: ei.tietoa@nn.oo

While approximately 10% of agriculture in Finland is still carried out on peat soils, the area involved is decreasing faster than the area of mineral soils. However, the large reserve of peatlands in Finland may become important in the future for agricultural production as a result of global climatic warming which would move the best agricultural areas northwards. Keywords: Agriculture, peat cultivation, peat soil, peatlands

• Heikkilä, Society of Peat Cultivation, Karelia Research Station, SF-82600 Tohmajärvi, Finland Sähköposti: ei.tietoa@nn.oo

The zinc contents of timothy grown on peat soils generally low in zinc were considerably raised by zinc fertilization, even when applied at the low rate of 550 g Zn/ha, in combination with other micronutrients. On peat soil groups with average extrac-table zinc contents of 0,60, 1,40 and 7,22 mg/1 the mean zinc contents of timothy before fertilization were 25,6, 27,1 and 28,9 and after fertilization 28,6, 34,8 and 36,4 mg/kg D.M., respectively. The corresponding increases were 11, 28 and 26 per cent. In general, the zinc contents of timothy in this study did not differ essentially from those measured elsewhere in Finland. Key words: Phleum pratense, zinc content, agriculture, peat soil, P/Zn.

• Urvas, Agricultural Research Centre, Department of Soil Science, SF-3J600 Jokioinen, Finland Sähköposti: ei.tietoa@nn.oo