Application of frass as fertilizer in organic viticulture: effects on the plant growth and on soil microarthropods ; tesi di master
Soil fertilization is critical for achieving the high yields required to feed an ever-increasing human population. Frass, a by-product of insect farming, may have a great potential as organic biofertilizer. This study aims to evaluate the fertilizing effect of Tenebrio molitor (L.) frass on organic vineyard. A field trial was implemented to compare the effect of mealworm frass and organic fertilizer (Phenix) with the same nitrogen dose, and control (unfertilized), on soil microarthropods and plant growth. Results showed that frass application gave QBS_ar value higher than the other treatments; however, it is not significantly different.
Although not statistically significant, frass applications increased SPAD and shoots growth in general. Only one variety, Uva di Troia, demonstrated that frass significantly performed better than control and Phenix. [...] Primitivo and Chardonnay varieties showed significantly better results than Phenix only for chlorophyll content parameter. Regarding sugar content and berries weight, frass resulted similar to Phenix. Despite the difficulty of detecting a short-term impact for an organic fertilizer, the results indicate that frass has a faster mineralization and high nitrogen availability, making it a promising fertilizer for vineyards. However, long-term experiments may quantify the significant positive effect of frass on plant growth and soil microathropods.