Effects of different irrigation volumes on the quantity and quality of forage harvested from Maralfalfa (Pennisetum sp.) at the experimental Station of IRED in N'Djamena (Chad)

Abstract This study, conducted at the experimental station of IRED in Farcha, N'Djamena/Chad, evaluated the effect of five irrigation water volumes (50%, 75%, 100%, 125%, and 150% of estimated requirements) on the quantity and quality of Maralfalfa forage (Pennisetum sp.) between November 2021 and May 2022. Water requirements were calculated by combining evapotranspiration (ETP), crop coefficient (Kc), and irrigation system efficiency. The results show that biomass production increases with the applied water volumes, but the growth rate diminishes beyond the plant's water needs. The water requirements of Maralfalfa (Pennisetum sp.) are lower than those of similar crops (alfalfa, maize). Furthermore, nutritional qualities (analyzed using near-infrared spectrometry, NIRS) varied slightly with water volumes. Lower water inputs produced forage with better nutritional quality but lower biomass yields. In conclusion, Maralfalfa (Pennisetum sp.) is a highly productive forage crop requiring moderate water volumes. Meeting the water requirements improves yields without significantly affecting forage quality. Keywords: Pennisetum sp., Maralfalfa, irrigation, nutritional quality, Chad.