Adaptability and harvest response of Panicum maximum under Mediterranean arid and semi-arid conditions

Harsh climatic conditions, including low rainfall, high temperatures, and soil sensitivity, pose significant challenges for forage production in Tunisian arid and semi-arid regions. Although several forage species have been evaluated in tropical and sub-tropical systems, their performance under Tunisian semi-arid and arid conditions, particularly under varying cutting schedules and saline irrigation, remains poorly documented. Selecting climate-resilient and high-yielding forage crops is essential to mitigate livestock feed deficits while ensuring economic and agronomic sustainability. This study provides the first multi-site evaluation of Panicum maximum in Tunisia, assessing its agro-morphological performance and adaptability under contrasting environmental conditions. A factorial experiment was conducted across two sites in Tunisia (central Tunisia: Sidi Bouzid; southern Tunisia: Médenine) over two years (2022–2023). The effects of site, cutting date (first vs. second cut), and year were evaluated on forage yield and agro-morphological traits, including plant height, number of branches, and leaf width. Forage yield was higher at the southern site (1.86 T/ha) than at the central site (1.25 T/ha DM), while the first cutting produced significantly more biomass (2.20 T/ha DM) than the second cutting (0.91 T/ha DM). Plant height was greater in the central site, indicating a trade-off between biomass production and morphological growth. Site × cutting and site × year × cutting interactions were observed for some traits, although yield remained relatively stable across years. Panicum maximum demonstrated strong adaptability and resilience under semi-arid and arid conditions in Tunisia. Optimizing harvest timing, particularly prioritizing the first cut, and adapting cutting strategies to local environmental conditions can enhance biomass production. These findings support the use of Panicum maximum as a sustainable forage resource to improve livestock feed availability in water-limited environments.