The Effect of Wool Mulch on Plant Development in the Context of the Physical and Biological Conditions in Soil

Mulching techniques can comprise a solution that better utilizes precipitation and irrigation water in such a manner that mitigates soil degradation and drought damage; however, there are still gaps in the literature with regard to the effect of the use of mulch materials on the development of plant–soil–microbe interactions. Waste fibers, as alternative biodegradable mulch materials, are becoming increasingly prominent. The effect of wool mulch (WM) on water use efficiency, with regard to pepper seedlings, was investigated in different soil types (sand, clay loam, peat) in a pot experiment. Two semi-field experiments were also set up to investigate the effect of WM–plant interactions on sweet pepper yields, as compared with agro textiles and straw mulches. Soil parameters (moisture, temperature, DHA, β-glucosidase enzymes, permanganate-oxidizable carbon) were measured during the growing season. The effect of WM on yield and biomass was more significant with the less frequent irrigation and the greater water-holding capacity of soils. Microbiological activity was significantly higher in the presence of plants, and because of the water retention of WM, the metabolic products of roots and the more balanced soil temperature were caused by plants. In the sandy soil, the straw mulch had a significantly better effect on microbiological parameters and yields than the agro textiles and WM. In soils with a higher water capacity, WM is a sustainable practice for improving the biological parameters and water use efficiency of soil. The effect of WM on yields cannot solely be explained by the water retention of the mulch; indeed, the development of biological activity and plant–soil–microbe interactions in the soil are also contributing factors.