Weed and Grassland Community Structure, Biomass and Forage Value Across Crop Types and Light Conditions in an Organic Agrivoltaic System

Agrivoltaics represents a crucial technology and an innovative solution to promote sustainability. After a cropping season in an agrivoltaic system in Northern Italy, this study investigated the floristic composition and biomass of weed communities across three crops, evaluating their variation under shaded and full light conditions. In addition, the research assessed the role of uncultivated grassland areas in agrivoltaic-shaded conditions by quantifying their biomass and evaluating their potential feed value. Weed floristic diversity and biomass were surveyed at three different times. Soil and canopy parameters were analyzed in relation to photosynthetically active radiation (PAR). Grassland biomass was assessed after four different cuts and its suitability as a feed source was evaluated by the pastoral value and near infrared (NIR) spectroscopic analysis. Results showed that tomato had the lowest weed presence, and Setaria italica and Sorghum halepense were predominant in rice, while in durum wheat, higher nutrient availability favored Echinochloa crus-galli and Cirsium arvense. In weed community composition and biomass, no significant differences were observed for the effect of different light conditions (sun/shadow), and this may be attributed to their high environmental plasticity. PAR was strongly correlated with both soil and canopy temperatures. The analysis of floristic composition, biomass yield, pastoral value and nutritional quality of grassland vegetation indicated that spring cuts can be effectively used as forage, including for grazing. These findings suggest that integrating livestock activities could offer a win–win strategy for managing uncultivated areas within agrivoltaic systems, thereby enhancing their sustainability under organic farming practices.