| Abstract [eng] |
Despite the economical and ecological benefit from short rotation energy forests, the development of these plantations is going very passively in Lithuania. There were two main goals of this work: to analyze current situation of development of willow plantations in Lithuania and to evaluate potential of using sewage sludge as substitute for mineral fertilizer for energy plantations. There are 470 ha of willow plantations in the Lithuania and 700000 ha could grow in Lithuania potentially in poor soils as alternative for agriculture crops. A problem of sewage sludge utilization is growing in Lithuania due to following reasons: sewage sludge treatments companies are not active in problem solving and looking for progressive technologies of sewage sludge utilization also the default of management of sewage sludge utilization for energy plantations fertilization. Current qualitative composition of sewage sludge in Lithuania conditions, that application amount of sewage sludge is limited not by heavy metals, but by nutrients (N and P). For this reason it is very important to determine rates, at which sewage sludge can be applied. The amount of 16 t/ha of dewatered swage sludge can be optimal (with assumption of 12% of N mineralization), because 90 kg/ha/yr N would be released to the soil and this amount of N is assimilated in willow stem per year on the average. If all current plantations were fertilized by sewage sludge (at the rate of 16 t/ha/yr), 12% of this organic manure would be utilized per year. There would be needed 4000 ha of energy forest plantations to utilize all sewage sludge aggregated per year. |
