Determination of the effects of different harvesting times and phosphorus doses on yield, quality, total phenolic compounds and antioxidant activity in vetch species

This study was conducted in Uşak in 2022-23, to determine the effects of different timing and phosphorus dose applications on the yield and quality of vetch varieties, as well as the total phenolic content and antioxidant activity. The experiment was designed as a randomised block design with a split-plot arrangement, and the experiment was replicated three times. Four different vetch varieties (common vetch, narbon vetch, Hungarian vetch, and hairy vetch) were placed in the main plots, whilst phosphorus doses (0 (control), 4, 8, and 12 kg/ha P2O5) were placed in the subplots. Cutting times (beginning of flowering, 50% flowering, full flowering, and seed harvest stage) were placed in the subplots. In the present study, the researchers sought to determine the levels of green forage yield, hay yield, seed yield, crude protein content, crude protein yield, NDF, ADF, total digestible nutrients (TDN), relative feed value (RFV), total phenolic content, antiradical activity (DPPH), copper reduction power (CUPRAC), tannin, phosphorus, potassium, calcium, and magnesium contents. According to the two-year averages obtained in the study, hairy vetch and Hungarian vetch were distinguished among the vetch species with regard to forage yield and quality. Increased phosphorus doses in phosphorus applications have been demonstrated to enhance both forage yield and quality, while delaying mowing stages has been shown to increase forage yield but reduce feed quality. With regard to seed yield, the highest yield was obtained from the narbon vetch species. It was found that increasing phosphorus doses improved both seed yield and quality. It was concluded that, in terms of green forage yield and quality, it would be more appropriate to prefer hairy vetch or Hungarian vetch, apply at least 8 kg of phosphorus per decare, and harvest at 50% flowering stage and for seed production, it would be more appropriate to prefer narbon vetch and apply 8 kg of phosphorus per decare.