Productivity of mechanized wood ash application in forest

Abstract

Importance of the study is determined by increasing consumption of woody biomass as a renewable energy source. Whole-tree harvesting is commonly applied for bioenergy use, however intensified biomass removal from forests can cause significant nutrient loss in soil. Nutrients can be returned to forest ecosystem by fertilizing soil with wood ash, which is generated as a by-product of combustion in wood-burning power plants and heating plants. Studies on ash spreading technological processes and costs so far have been insufficient. Aim of the study is to compare the productivity and prime cost of ash spreading with modular spreading trailer and Amazone mineral fertilizer spreader. According to study results productivity of modular trailer is 0.57 ha h-1 and the spreading costs are 88 EUR ha-1, but that of mineral fertilizer spreader Amazone-0.61 ha h-1 and 41 EUR ha-1, respectively. Despite lower productivity modular trailer is more suitable for spreading wood ash, because a larger amount can be delivered and ash is applied more evenly. Productivity of modular trailer can be increased by technical improvements, like equipping the tractor with a crane and a small excavator bucket. Comparing costs of ash spreading and deposition, additional 8.72 EUR ha-1 were required, when using modular trailer, whereas, when using mineral fertilizer spreader, 77.52 EUR ha-1 can be saved. The main reason for the difference is smaller dosage when using modular spreader and additional loading costs.