Enrichment of peat with a protein hydrolysate-based biostimulant obtained from wine lees: effect on pepper plants

Currently, the use of biostimulants is considered an environmentally friendly alternative to synthetic fertilizers. In this work, we investigated the use of a biostimulant obtained from winemaking sludge by enzymatic hydrolysis processes in peat enrichment. The aim was to observe how this biostimulant affects the growth and development of green pepper (Capsicum annuum L. cv. Italian) seedlings. The biostimulant was applied in three doses (1, 2, and 3 g/L) for a total of four applications. Seedlings were harvested at a height of 8–16 cm and with 5–7 leaves. Plant height, weight of aboveground and belowground parts, macro- and micronutrient contents, photosynthetic pigments in leaves, and enzymes related to plant stress were determined. The results obtained indicated that plant height, weight of the aboveground and belowground parts, and macro- and micronutrient content in the aboveground and root parts were higher in plants treated with the highest dose of biostimulant. Compared with the control treatment (without amendments), the contents of chlorophyll a, chlorophyll b, and total carotenoids increased by 57%, 51.9%, and 53.1%, respectively, in plants treated with the highest dose of biostimulant. These results suggest that peat enrichment with this biostimulant could be useful for improving bell pepper quality.