The Changes of Willow Biomass Characteristics During the Composting Process and Their Phytotoxicity Effect on Sinapis Alba L.

This study evaluated the use of willow chips for compost production and its effect on Sinapis alba L. germination index and seedling growth. A compost experiment with willow biomass was conducted to study its effect on selected compost indexes (particle structure in %, bulk density (kg m -3 ), and total nitrogen content). The quality assessment of the willow composts was determined after six months of composting process based on the N content and morphological characteristics of tested plant in vegetative chamber. Sinapis alba L. was germinated on a water extract made from willow compost using the following additives to willow biomasses: W0 - without additives, WN - with the addition of nitrogen, WF - with the addition of mycelium, WNF - with the addition of nitrogen and mycelium. During the composting process, samples were taken after each mixing of the bio-mass pile to assess their maturity through the use of a bioassay. Willow biomass did not have a negative effect on biological evaluation parameters, and in some indicators, such as the length of embryonic roots in the VI period of the measurements, it was stimulating (61-84% longer in W0 and WF than in the control). The addition of nitrogen during the composting process, especially in the initial composting period, had a strong inhibitory effect.