A spray-on environmentally friendly degradable mulch material and its high efficiency in controlling above-ground biomass of weeds in greenhouse experiments

Abstract

This study describes a novel spray-on mulch material as an alternative to currently used weed control methods. The mulch material is based on renewable raw materials, mainly rapeseed oil, starch and sodium alginate. Laboratory tests were conducted to obtain a mulch material with the best possible properties. Formulations with different ingredients were prepared and tested for their material properties. The formulations were investigated for potential shrinkage tendency and heat resistance as well as water resistance. Further tests such as resistance to mould infestation and aerobic degradability according to DIN EN ISO 17556 were carried out with the formulation that performed best in the previous tests. Mould resistance was enhanced by adding sodium benzoate. In the laboratory experiment, the CO2 decomposition rate was about 30% after seven weeks. With the favouritised variant, which was found step by step through the experiments, an outdoor field test was carried out to investigate the durability under natural conditions over the vegetation period. In the field, the mulch material maintained its function for six months. In the greenhouse, the effect of the mulch material on weeds was studied. It was found that the mulch material showed a high efficiency in controlling above-ground biomass of Elymus repens, Amaranthus retroflexus, and Setaria viridis. In addition, the biomass of the roots of Amaranthus retroflexus and Elymus repens was reduced. Further studies are on the way to elucidate field suitability and the weed suppressive effect under different environmental conditions.