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Raimo Kõlli and Arno Kanal

The management and protection of soil cover: an ecosystem approach

There is need for increased societal awareness of the importance of soil management for varying specific uses and for protection of the environment. The main purpose of the study was to analyze the role of soils in the formation and function of ecosystems, to elucidate the properties and mechanisms which play the main role in plant-soil mutual relationships, and to generalize the pedoecological principles of soil management and protection in conditions of Estonia. The treatment is a departure from the pedocentric viewpoint and is based on an ecosystem approach. The relationships between soil and plant covers are tested quantitatively on the basis of the ecosystems' phytoproductivity and fluxes of organic carbon, and qualitatively on the ground of humus forms and site types. On the basis of personal research and data available in literature, the constraints limiting soil cover functioning, the soil degradation features which occurred in actual time and the measures and activities for prevention of soil degradation are analyzed. Problems connected with biodiversity and soil environment protection ability as they relate to soil cover management and protection are discussed. For sustainable land use and to avoid deterioration of soil properties, the experience of local farmers, scientific research and monitoring of degradation features are needed. The soil cover is protected (or sustainable land use is attained) in circumstances when soil fertility and functioning is maintained adequately for the soil types' characteristics. Soil cover should be considered as a medium through which it is possible to improve the environmental status of the area.

Open access

Raimo Kõlli, Endla Asi, Lech Szajdak, Tõnu Tõnutare, Alar Astover and Kadri Krebstein

Abstract

This article studied the extent of accumulation of aqua regia extractable metallic elements (Al, Mg, Pb, Zn, Hg, Cd) into peaty (histic) epipedon (EP) of fen soils, transitional bog soils, peaty gley soils and peaty podzols. The accumulation coefficients (Kac) of the elements in EP were estimated in relation of forest floor (FF, as an input) as a comparison to deeper levels (SS, as a past background). The study revealed that the extent of accumulation and its order depend on soil (peat) type or pedo-ecological conditions of peatification. In the forming of EP from FF, the concentrations of Al and Pb were increased on an average 2.5-5.0 times, but that of Hg increased significantly only in peaty soils (on an average 1.5-1.6 times). The contents of Zn were significantly decreased (Kac 0.1-0.5) in all soil groups. The comparison of EP peats concentrations with SS data demonstrated a considerable accumulation of Pb, Cd, Zn and Hg into thin (~20 cm) superficial peat layer.

Open access

Mait Lang, Raimo Kõlli, Maris Nikopensius, Tiit Nilson, Mathias Neumann and Adam Moreno

Abstract

Optical remote sensing data-based estimates of terrestrial net primary production (NPP) are released by different projects using light use efficiency-type models. Although spatial resolution of the NPP data sets is still too coarse (500–1000 m) for single forest stands, regional monitoring of forest management and growth with 25–100 ha sampling units is feasible if the NPPSAT estimates are sensitive to forest growth differences depending on soil fertility in the area of interest. In this study, NPP estimates for 2,914 mixed forest class pixels (according to the MODIS land cover map) located in Estonia were (1) obtained from three different NPPSAT products, (2) calculated using an empirical soil potential phytoproductivity (SPP) model applied to a 1:10,000 soil map (NPPSPP), and (3) calculated using stem volume increment estimates given in a forest management inventory data base (NPPFIDB). A linear multiple regression model was then used to explore the relationships of NPPSAT with the proportion of coniferous forests, the NPPSPP and distance of the pixels from the Baltic Sea coast – the variables that have been found informative in previous studies. We found a positive moderate correlation (0.57, p < 0.001) between NPPSPP and NPPFIDB. The local or downscaled meteorological data-based NPPSAT estimates were more consistent with the NPPSPP and NPPFIDB, but the correlation with NPPSAT was weak and sometimes even negative. The range of NPP estimates in NPPSAT data sets was much narrower than the range of NPPSPP or NPPFIDB. Errors in land cover maps and in estimates of absorbed photosynthetically active radiation were identified as the main reasons for NPPSAT inconsistencies.