Grundlagen zur Wahl zweckmassiger Bodenabdeckverfahren in Fichtenverschulbeeten | Fundamentals of the evaluation of suitable materials for soil covering in spruce transplant beds. [Picea] | Fundamentals of the evaluation of suitable materials for soil covering in spruce transplant beds

In 1965 and 1966 protective coverings of the soil (mulching) with foils (plastic, paper, tar paper, aluminum) and peat were compared with uncovered, mechanically cultivated controlls in spruce transplant beds on a clay rich “Braunerde-Pseudogleystandoft” (approx.: graybrown podsolic soil with surface water influence) in the “Vorderer Flyschwienerwald” (Vienna woods). Dark foils (plastic, tar paper) caused an increase of the daily maximum temperatures and of the temperature amplitudes of the soil, while light coloured foils (paper, aluminum) and organic mulches (peat) caused a decrease; the minimum temperatures during the nights were moderated by all mulching methods. Every covering caused an increase of soil moisture in the upper layers and a decrease in the lower layers. Precipitation retention of the impermeable materials (plastic, aluminum) is almost completely compensated by the lowered evaporation from the soil. Every covering increased soil fauna quantitatively and enlarged pore-volume or decreased soil density respectively. Every covering caused daily air temperature maxima and minima to increase. Smooth foils increased maximum temperatures more than rough ones. Evaporation was increased by dark materials (plastic), which absorb mainly heat radiation, while peat and aluminum coverings lowered it. Dew fall was lower over foils than over uncovered soil, condensation was most heavy on materials impermeable to air. Weeds coming up between the mulching materials impeded the quality of the transplant stock only slightly. Shading weeds caused elongations of the stems, permanently suppressive weeds caused growth inhibitions by more than a half. Covering influenced the roots of the transplants much more pronounced than the shoots, but not quite to the extent expected on the ground of ecological observations. Soil temperature increasing materials (plastic, tar paper) augmented above all the subsurface stockyness (root length, fine root percentage), peat mulching caused height and growth increments. The following, statistically significant correlations between plant data and ecological data could be observed: root development and sprouting—soil temperature, secondary shoots—soil misture, colour of the needles—albedo of the covering material. Profitableness of covering increased with increasing duration of the transplant state. In case of a one year duration mechanical cultivation was competitive; more than two years a~er transplantation peat mulching lowered tending costs by 15 per cent and covering with tar paper or plastic foil by 35 per cent. Based on these experiments soil covering with plastic foil as well as tar paper and peat can be recommended for practical applications.