Wood Chips from Hedgerows – Biomass Potential for On-Farm Mulching and Bioenergy?

Summary

Hedgerows are landscape features with ecological value and agricultural benefits which are appreciated in organic farming. Biomass from periodical cutting down of hedgerows is often unutilized litter. The study assesses different ways how to use wood chips from hedgerows, and quantifies the biomass potential for either mulching arable land with wood chips or, alternatively, for bioenergy use. The calculations are based on experiments at the experimental station for organic farming Kleinhohenheim and on literature. The yield of wood chips was clearly too low to mulch the total arable land of the model farm. Hedgerows on an area equal to 1% of the farm area yielded wood chips for 0.05 ha if 160 m3 ha-1 were applied. This layer significantly reduced weeds. Hedgerows covering 5% or 20% of the farmland would provide wood chips for about 0.2 or 1 ha for mulching or, used as firewood, they would cover the corresponding fuel oil demand of more than one average household. Compared to poplars in short rotation coppice on the same area, the energy output is low. Since an energy use of wood chips is ecological and economical inefficient, mulching seems a reasonable way to use wood chips from cutting hedgerow, in spite of low yields. Wood chips should be applied to thoroughly selected areas, such as slopes (protection from soil erosion), crops with wide inter-row-distance or to perennial, high-value crops.