Artikkelit jotka sisältää sanan 'nutrients'

Commercial thinning is a common practice when growing even-aged stands in the Nordic countries. Thinning from below is carried out to harvest suppressed and part of the mid-sized trees that cannot successfully compete for resources and have become grown over by co-dominant and dominant trees. In five field experiments, we studied the effects of harvesting method on the nutrient amount of logging residues left at the site in thinning of Scots pine stands. Comparison was carried out between four harvesting methods representing different levels for forest-residue recovery: SOH (stem-only harvesting down to a diameter of 7 cm, SOH-E (stem-only harvesting down to a diameter of 2 cm),WTH (whole-tree harvesting including stems, tops and branches) and WTH-M (WTH and manual collection of those logging residues which were left in mechanical harvesting). In each experiment, logging residues were weighed and sampled for determination of their nutrient concentrations, and soil samples were taken from the surface peat layer (0–20 cm) for nutrient analyses. In SOH treatments, all residues and nutrients bound in the logging residues were left at the site. In WTH 28–67% and in WTH-M 4–20% of the nutrients remained at the site, with the figure depending on the experiment. The amounts of N (1%), P (1–4%), Ca (2–5%), and Mg (3–8%) bound in the logging residues in SOH were low in comparison to the corresponding amounts in the 0–20 cm peat layer. However, the amount of K in logging residues represented 10–26% and the amount of B 8–15% compared with the corresponding nutrients in peat. The amount of N, P, and K in logging residues after CTL harvesting was 39–86, 3–7, and 9–21 kg•ha-1, respectively. The corresponding figures after WTH were 15–36, 1–3, and 3–9 kg ha-1. We assume that WHT on peatland sites that are prone to K deficiency or already have a detected shortage may increase a risk for nutrient imbalances and growth loss in remaining tree stand.

• Hytönen, Natural Resources Institute Finland, Silmäjärventie 2, 69100 Kannus, Finland Sähköposti: ei.tietoa@nn.oo
• Moilanen, 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

A natural understorey of Norway spruce often develops under birch on oligo-mesotrophic peatlands, but spruce can also be planted on these sites. The effects of fertilization and the density of the pubescent birch nurse crop on the height growth and needle nutrient status of a planted spruce understorey on an old drained herb-rich sedge pine fen was investigated in this study. The spruce transplants were planted early in the 1960’s. The nurse crop was removed, thinned to 200 stems ha-1 or left unmanaged in 1988. A number of plots were also fertilized. The height growth of the spruce transplants was measured during two periods after management, and the needle nutrient concentrations were determined before fertilization and again 10 years later. The height growth of the spruce was 40 - 60% greater after removal of the nurse crop than that under the unthinned nurse crop. Even the thinned nurse crop slowed down the growth of the understorey. However, height growth was the best on the plots on which the nurse crop was removed and the plots fertilized.

• Hilli, OSLA, Kirkkotie 1, FIN-91500 Muhos, Finland Sähköposti: ei.tietoa@nn.oo
• Päätalo, Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo
• Piiroinen, Sähköposti: ei.tietoa@nn.oo

Relationships between the peat nutrient concentrations and the degree of humification, the ground vegetation and the botanical composition of the peat were studied on an afforested, originally treeless mire with a wide nitrogen gradient. The afforestation was carried out in 1971 using spot sowing and spot fertilisation. A broadcast fertilisation experiment that involved six replicates with four treatments, (i) a control, (ii) PK (rock phosphate and KCl), (iii) PK+ B, Cu and (iiii) wood ash was established in 1981–82. The surface peat layers were sampled for nutrient analyses in 1995 and for peat type determinations in 1997. The ground vegetation was inventoried in 1995. In 1995, the peat total nitrogen concentration varied from 8.7 to 29.1 mg g-1 in the 0–5 cm peat layer. The total nitrogen, phosphorus and iron concentrations and the degree of humification in the peat were all positively correlated with the proportion of Carex components and with each other. The frequency of Sphagnum mosses correlated negatively but that of forest mosses positively with the peat total nitrogen concentration. Broadcast fertilisation with wood ash increased the concentrations of phosphorus, potassium, calcium, magnesium, manganese, boron, copper and zinc especially in the 0–5 cm peat layer but did not affect other peat properties or the ground vegetation.

• Hartman, Finnish Forest Research Institute, Vantaa Reseach Centre, P.O. Box 18, 01301 Vantaa Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo
• Silfverberg, Sähköposti: ei.tietoa@nn.oo

The effects of drainage maintenance on the nutrient contents in peat and Scots pine needles on drained pine mires were studied. The material consisted of twelve Finnish field experiments. Drainage maintenance (increasing ditching intensity; no treatment at all, mere ditch cleaning, mere complementary ditching, and both of them together) was carried out in 1982-1985. The needles were sampled in 1994-1995 and peat in 1996. There were great differences in the site types and consequently also in the peat and needle nutrient concentrations between the experiments. The needle Mn concentrations demonstrated a fairly good drainage status in all the treatments. Drainage maintenance had only minor effects on the nutrient status of peat and needles. Ditch cleaning decreased magnesium, manganese and zink amounts in the surface peat. Increasing the intensity of drainage maintenance increased the 100-needle dry mass, but decreased the needle boron concentrations. Peat and needle nitrogen concentrations increased slightly (not significantly) along with the increased intensity in drainage maintenance. The peat nutrients classified correctly 83.7% of the fertility classes for drained peatlands.

• Lauhanen, The Finnish Forest Research Institute, Kaironiementie 54, FIN-39700, Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo

The present study looked into the soil properties of twenty-four peat-based field by examining the 0-10, 10-20, 20-30 and 30-40 cm soil layers and thc effect that soil properties have on the initial development of young stands of downy birch growing in Pohjois-Savo, southern Finland. Adding of mineral soil to peat-based fields and the decomposition and subsidence of peat had resulted in increasing the bulk density of the peat, especially in the tilling layer. Also, the amounts of nutrients in the tilling layer were higher than in the layer below. Together with fertilization, the addition of mineral soil had increased the soil's nutrient amounts manyfold compared to virgin mires and mires drained for forestry. Eighthy-one per cent of the trees were alive. The share of viable trees had fallen to half of the planting density, being now just 840 trees per hectar. The increase in the amount of extractable potassium and total copper in the soil improved the growth of young stands and reduced the proportion of trees of inferior quality. Growth disorders were observed in downy birch, and these were probably caused by increases in the ratios of the amounts of main nutrients and micro-nutrients in the soil. The ratio of nitrogen and phosphorus to copper was reflected best of all in the growth of young stands. An increase in the amount of soil nitrogen and phosphorus in relation to the amount of soil copper impaired stand growth and promoted the occurrence of trees afflicted by growth disorders.

• Hynönen, Pohjois-Savo Forestry Centre, P.O. Box 1019, FIN-70101 Kuopio, Finland Sähköposti: ei.tietoa@nn.oo
• Makkonen, Sähköposti: ei.tietoa@nn.oo

The effects of fertilization and refertilization on the growth of pubescent birch (Betula pubescens) stands growing on drained peatlands in northern Finland were studied in eight field experiments. The treatments were: (i) control with no fertilization, (ii) fertilization with nitrogen (N), (iii) fertilization with phosphorus and potassium (PK), and (iv) fertilization with nitrogen, phosphorus, and potassium (NPK). The sites represented four different mesotrophic to eutrophic site types with stand median heights ranging from 7 m to 13 m. Tree growth was monitored at stand level during periods of five to eleven years following the setting up of the experiments and during periods of 4 to 7 years following the repetition of the treatments in 1985. At the end of the second period, sun-exposed leaves were sampled from two stands in August 1990 for the purpose of conducting foliar nutrient analyses. The first-time fertilization treatments did not affect tree growth on any of the site types. Following the repetition of the treatments, the stands responded positively to NPK or PK fertilization on all site types except on the shallow-peated herb-rich peatland forest. There was no response to mere N-fertilization on any of the site types. The growth responses observed were weaker than those reported for Scots pine in similar climatic conditions. Key words: Betula pubescens, foliar nutrients, growth responses, nitrogen, peatland, phosphorus, potassium

• Penttilä, The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo

Chemical and physical characteristics of afforested peat fields were compared with those of neighbouring peatland forests, i.e. naturally forested peatland sites drained to improve forest growth. Six study sites were selected with such sites located alongside an afforested peat field. On three of the fields, mineral soil had been added during cultivation as a soil amelioration agent. Most of the fields had been cultivated for 15–20 years before afforestation. Volumetric soil samples were taken and analysed for their total and ammonium acetate extractable nutrient concentrations (P, K, Ca, Mg, Mn, Fe, Zn). Kjeldahl N and B in H3PO4–H2SO4 were also analysed. The soil layers 0–20 cm (the field cultivation depth) and 20–40 cm were compared. The physical and chemical characteristics of the top soil in peat fields and neighbouring forests differed in many respects even after 25 years had passed since their afforestation. Bulk density, ash content and pH of the peat were higher in the cultivation layer of the fields than in the corresponding layer in peatland forests. In cases where mineral soil had been added to the peat fields, the amounts of P, K, Ca, Mn and Zn were higher in the 0–20 cm soil layer whereas the amounts of N and B did not significantly differ from those in the soils of peatland forests. The differences in the amounts of extractable nutrients between the field soils and forests soils were smaller; Ca and (when mineral soil had been added) also Fe and Zn concentrations were higher in the peat field soils than in the soils of peatland forests.

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

Abstract: The foliar chemical composition of a Norway spruce underwood were analysed one year before and in three years after the removal of a downy birch (Betula pubescens Ehrh.) shelterwood on an old drainage area. The most remarkable change due to the release was considered to be the significant decrease in the potassium concentrations. The nitrogen concentrations increased very strongly, and phosphorus increased slightly but not significantly during the first growth period after the release, decreasing later to a level approaching the deficiency limit. Consequently the nutrient balance between N and K was strongly shaken by the increased N/K-ratio. One reason for that might be the increased use of K in the growing points of roots after the root competition of shelterwood was eliminated. Key words: foliar analysis, nutrients, peatlands, Picea abies, shelterwood, underwood.

• Saarinen, The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo

Abstract: The stand-level responses to fertilization and refertilization were studied in seven factorial field experiments established in 1974-1976. The factors were nitrogen fertilization (N) and phosphorus-potassium fertilization (PK). The factorial treatments were applied at two levels: (i) control and (ii) fertilized with a dosage following the currently used Finnish forest fertilization guide-lines. The spruce-dominated stands were selected from areas drained according to normal forestry practises between 1932 and 1969. The sites covered fairly well the trophic variation that occurs on spruce-dominated peatlands in the mid-boreal zone in Finland. Tree growth was monitored during two periods of five to seven years. The second period followed the refertilization in 1985. At the end of the second period, one-year-old sun-exposed needles were sampled from the four southernmost stands for nutrient analyses. The effects of fertilization on tree growth were generally fairly weak and insignificant, especially during the first study period. After refertilization, the effect of N was positive in three stands on mesotrophic sites. The foliar nutrient analyses of unfertilized spruces showed low concentrations of N, P and Cu. PK-fertilization increased foliar P concentrations and, in some cases, also K concentrations. Since the PK-fertilizer included some borate, it also increased foliar B concentrations. N-fertilization did not affect foliar N, P or K concentrations but it decreased foliar concentrations of Ca, Zn, and B in some cases. Both the growth responses and the foliar nutrient analyses indicated that nitrogen was the most deficient macro-nutrient. Key words: foliar nutrients, growth responses, mires, nitrogen, phosphorus, Picea abies, potassium

• Moilanen, The Finnish Forest Research Institute, Muhos Research Station, Kirkkosaarentie, FIN-91500 Muhos, Finland Sähköposti: ei.tietoa@nn.oo
• Penttilä, Sähköposti: ei.tietoa@nn.oo
• Issakainen, 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

This paper is based on four experiments established in 1960-1969. There were four sources of potassium: potassium chloride, double salt of potassium and magnesium sulphates, cement potassium and potassium sulphate. The application rates of fertilizer potassium varied from 0 to 664 kg/ha as pure element. Nitrogen and phosphorus or phosphorus alone were also given at the beginning. The experiments were inventoried in 1988. The peat potassium amounts were independent of the application rate. On the other hand, the foliar potassium concentrations were the higher the higher the application rate. Yet, the effect of currently used potassium fertilizer rate, (about 80 kg/ha of K), on the foliar potassium concentrations did not significantly differ from the effect of the double rate. Fertilization increased the basal area growth for 8-22 years, after which the growth started to decline. The reason can at least partly be attributed to the shortage of potassium. The growth response was independent of the potassium source and rate on the potassium fertilized plots. Key words: Foliar nutrients, peatland, peat nutrients, Pinus sylvestris

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

The variation in groundwater nutrient concentrations from 29 oligotrophy pine mires were described. The relationships between groundwater chemistry and the chemical status of the surface peat layer were also investigated. The mean groundwater quality in different site type fertility groups was: pH 4.0-4.8; NH4+-N 0.45-0.80 mg l-1; P 0.06-0.15 mg l-1; K 0.27-0.54 mg l-1 ; Ca 1.40-3.78 mg l-1; Mg 0.49-1.67 mg l-1; Mn 0.01-0.12 mg I-1; Fe 0.69-3.20 mg l-1; Al 0.34-0.57 mg i-1; Zn 0.006-0.015 mg I-1; Na 0.63-1.91 mg l-1; B 0.008-0.010 mg l-1 and S 1.15-1.47 mg l-1. When ordered from the most infertile to the most fertile site types, groundwater pH and total concentrations of Ca, Mg, Mn, Fe and Na significantly (P < 0.001) increased. There was a large seasonal variation in the concentrations of S, K, Na, B and Zn, and a large within-plot variation in K, NH4+-N, P and B concentrations. The results indicated that factors other than the chemistry of peat were involved in determining the concentrations of these nutrients in the groundwater. Groundwater concentrations of Al, Fe, Ca and Mg, on the other hand, were found to be strongly correlated with the corresponding total nutrient concentrations in the surface peat layer. Keywords: peatlands, peat nutrients, water chemistry

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

The alder mixture and fertilization, both separately and especially together increased the growth of pine and the mass and length of roots, and decreased mortality of trees. Alder mixture increased the amounts of phosphorus and potassium in peat as compared to the alderless plots. The thickness of the peat layer (range 0.24-0.72 m) was negatively correlated with the growth of pine, the foliar P and K concentrations and the root mass and length. In no case were roots found in the peat layer closest to the subsoil. Obviously the peat layer should not be thicker than 30 cm, even if fertilized, for growing pine in a peat cutover area. Keywords: Foliar nutrients, peat nutrients, peat thickness, root penetration

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