Analyses of the Potential Use of Sludges in Forestry and Parks


1PhD student, Faculty of Agriculture and Environment, Agricultural University of Tirana

2Lecturer, Faculty of Agriculture and Environment, Agricultural University of Tirana

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Forestry can potentially provide opportunities for using sludge where large areas are available locally to
WWTP. Sludge is most useful at the time of planting seedling trees as this improves establishment and early
growth; this is particularly important in areas where trees and other vegetation are planted for soil erosion
control. Sludge may also be applied to mature forests where the additional nutrients can improve timber yield.
However, delivery and application of sludge is constrained by topography as access for vehicles may be difficult
and where the land is steep, application by hand may be necessary. The forestry growth cycle is long and
nutrient demands may be modest, although they can be high in newly afforested areas as soil are generally very
poor, or if replanting is carried out on clear-felled areas as the previous tree crop depletes the soil of nutrients. In
intensively managed forestry, the intervals between sludge applications are extended, depending on access, the
fertility of the soil, and the growth stage and nutrient status of the trees. The optimum operation window is at
(re)planting when the area is open. Sludge can be applied mechanically if ground conditions permit and rates
may need to high if the soil is impoverished (up to 50 t ds/ha). Where access is difficult, manual addition of
sludge can be made to individual tree plantings, and a few kilograms of sludge should be mixed with the soil for
each seedling. Sludge applied at this time has a significant economic benefit as seedling establishment is
substantially improved, reducing the costs of replacing failed seedlings.

Keywords: waste; sewage; sludges; heavt metals.

Post Author: MVhDC39RHa