Co-composting of algae and effect of the compost on germination and growth of Lepidium sativum

In order to obtain a value-added product from the removal and processing of waste algal biomass, it is essential to elaborate on cost-effective methods of their utilization. Composting appears to be one of the methods of obtaining a natural fertilizer. This paper demonstrates the results of a study where the biomass of seaweed (Fucus sp.) has been co-composted with ecological hay, grass, sawdust, and spent mushroom substrate for three months. The utilitarian properties of the new natural products (compost and compost extract) were examined in germination tests on Lepidium sativum. Three groups were compared: the control group treated with distilled water, and two experimental groups: one treated with seaweed extract and the other fertilized with algal compost. Results showed that the addition of compost and compost extract contributed to the increase in plant length and mass. Moreover, the biomass fertilized with new products was rich in micro- and macroelements (in particular B, Fe, Cu, Zn, Ca, K, S). Utilization of algal biomass for agricultural and horticultural purposes could be benefi cial for environmental protection in that it might help remove waste biomass from coastal areas and from the point of view of the economy by resulting in the production of value-added natural fertilizers and biostimulants (extracts). The latter could help reduce the use of chemical fertilizers and could help to improve physicochemical properties of the soil, thus producing an enhanced seed yield.