LIVESTOCK MANURE MULCHING AND BACTERIAL INOCULATION AS ALTERNATIVE STRATEGIES TO ENHANCE EARLY TREE ESTABLISHMENT ON SAND AND GRAVEL EXTRACTION SITES

Abstract

Land reclamation following the extraction of mineral resources (e.g., peat, sand, and gravel) is essential to restore the ecological functions and economic value of disturbed areas. Soils at sand and gravel extraction sites are typically impoverished — exhibiting low organic matter content, poor water retention, and unfavourable structure. To improve the fertility of such soils and support the successful establishment of forest stands and other vegetation, soil amendments are required. Among the most effective methods is the use of organic fertilizers, which improve soil structure and nutrient availability. This study was carried out in a reclaimed sand and gravel mining site where several tree species – silver birch, black alder, Norway spruce and Scots pine, were planted, and three types of organic livestock manure – swine, cattle, poultry, commonly used in agriculture, were applied as mulching materials. In addition, . Results indicated that cattle fertilizer enhanced the growth of birch, while poultry fertilizer promoted pine growth. However, the most pronounced effects were observed with swine additive, which positively influenced birch, alder, and pine. Spruce showed no response to any of the fertilization treatments. Across species, the addition of Bacillus megaterium had limited or species-specific effects, enhancing growth only in a few fertilizer combinations. Seedling type, moreover, did not account for a substantial proportion of the variation in height increment across the studied species.