Timo Kareinen, Ari Nissinen, Hannu Ilvesniemi. (1998). Analysis of forest soil chemistry and hydrology with a dynamic model ACIDIC. Acta Forestalia Fennica no. 262 article id 7522. https://doi.org/10.14214/aff.7522

Keywords: simulation; modelling; aluminium; leaching; water flow; cation exchange; macropores; micropores; flow paths

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In this study we analyse how the ion concentrations in forest soil solution are determined by hydrological and biogeochemical processes. A dynamic mode ACIDIC was developed, including processes common to dynamic soil acidification models. The model treats one to eight interacting layers and simulates soil hydrology, transpiration, root water and nutrient uptake, cation exchange, dissolutions and reaction of Al hydroxides in solution, and the formation of carbonic acid and its dissociation products. It includes also a possibility to a simultaneous use of preferential and matrix flow paths, enabling the throughfall water to enter the deeper soil layers in macropores without first reacting with the upper layers. Three different combinations of routing the throughfall water via macro- and micropores through the soil profile is presented. The large vertical gradient in the observed total charge was simulated successfully. According to the simulations, gradient is mostly caused by differences in the intensity of water uptake, sulphate adsorption and organic anion retention at the various depths. The temporal variations in Ca and Mg concentrations were simulated fairly well in all soil layers. For H⁺, Al and K there were much more variation in the observed than in the simulated concentrations. Flow in macropores is a possible explanation for the apparent disequilibrium of the cation exchange for H⁺ ad K, as the solution H⁺ and K concentrations have great vertical gradients in soil. The amount of exchangeable H⁺ increased in O and E horizons and decreased in the Bs1 and Bs2 horizons, the net change in whole soil profile being a decrease. A large part of the decrease of the exchangeable H⁺ in the illuvial B horizon was caused by sulphate adsorption. The model produces soil water amounts and solution ion concentrations which are comparable to the measured values, and it can be used in both hydrological and chemical studies of soils.

Kareinen, E-mail: tk@mm.unknown
Nissinen, E-mail: an@mm.unknown
Ilvesniemi, E-mail: hi@mm.unknown

Category : Research article

article id 420, category Research article

Jukka Matero. (2004). Cost-effective measures for diffuse load abatement in forestry. Silva Fennica vol. 38 no. 3 article id 420. https://doi.org/10.14214/sf.420

Keywords: buffer strips; cost effectiveness; drainage maintenance; nutrient leaching

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This paper theoretically and empirically analyzes the design of cost-effective diffuse load abatement in forestry. Harvesting with related forest regeneration and drainage maintenance increases nutrient leaching, while riparian buffer strips and adjustments in drainage maintenance technology can be used to prevent this leaching. By utilizing a two-period model it is shown that cost-efficiency requires the establishment of a buffer strip system and a reduction in both current harvesting, and in drainage maintenance – if practized – relative to the private optimum to reflect their effects on water pollution. A simulation analysis was conducted to assess the magnitudes of the decision variables of the theoretical model, as well as to evaluate alternative technologies for the implementation and use of buffer strips and for the adjustment of drainage maintenance. The results for a representative forest holding in the southern half of Finland show that it is possible to considerably reduce total phosphorus leaching with minor cost.

Matero, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: jukka.matero@joensuu.fi

article id 422, category Research article

Mika Nieminen. (2004). Export of dissolved organic carbon, nitrogen and phosphorus following clear-cutting of three Norway spruce forests growing on drained peatlands in southern Finland. Silva Fennica vol. 38 no. 2 article id 422. https://doi.org/10.14214/sf.422

Keywords: hydrochemistry; forest regeneration; peatland forestry; leaching; nutrient losses

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The effect of clear-cutting on the concentrations of dissolved organic carbon (DOC), organic nitrogen (DON), NH4+, NO3–, and P in outflow water from three productive, Norway spruce dominated drained peatlands (RCC, VCC-1, VCC-2) were studied. Changes in runoff and transport loads (concentration x runoff) at two of the catchments during the frost-free period are also presented. Approximately 40% of the area was cut at RCC and VCC-2, and 72% at VCC-1. The volume removed was 250 m3 ha–1 at RCC, 259 m3 ha–1 at VCC-1, and for VCC-2, 317 m3 ha–1. The mean annual increase in outflow concentrations of DOC during the first four years after clear-cutting was 9.0 mg l–1 at RCC, 22.8 mg l–1 at VCC-1 and 8.4 mg l–1 at VCC-2. Corresponding increases in the forms of nitrogen were: 0.23, 0.51 and 0.16 mg DON l–1; 0.06, 0.31 and 0.04 mg NH4+-N l–1; and 0.05, 0.12 and 0.22 mg NO3–-N l–1. Clear-cutting did not significantly (p > 0.05) increase P concentrations. The increase in non-frost season runoff over the first three years after clear-cutting was 107 mm at RCC and 207 mm at VCC-1. The export loads of DOC during the non-frost season increased by 80 kg ha–1 at RCC and by 184 kg ha–1 at VCC-1 over the first three years. Corresponding increases for the other studied solutes were: 1.78 and 3.98 kg DON ha–1; 0.39 and 1.49 kg NH4+-N ha–1; 0.45 and 0.48 kg NO3–-N ha–1, and 0.09 and 0.06 kg P ha–1. The study demonstrated that clear-cutting may significantly increase the export of DOC and different forms of nitrogen from drained productive peatlands while only small increases in phosphorus export may occur.

Nieminen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: mika.nieminen@metla.fi

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