Impact of Inter-Annual Rainfall Variability on the Forage Quality and Mineral Composition of Cenchrus ciliaris L.

Abstract

Inter-annual rainfall variability is a key driver influencing forage productivity, nutritional quality, and mineral composition in semi-arid grassland systems. This study models the impact of rainfall fluctuations on the forage quality and mineral dynamics of Cenchrus ciliaris L., a widely cultivated pasture species in dryland agriculture. Field data were collected over multiple growing seasons characterized by contrasting rainfall patterns, and analyzed to assess variations in biomass quality, crude protein content, fiber fractions, and essential mineral concentrations. The results indicated that rainfall variability significantly affected both the quantity and quality of forage, with moderate and well-distributed rainfall enhancing nutrient accumulation and improving digestibility. In contrast, low and erratic rainfall conditions led to reduced crude protein levels, increased fiber content, and imbalanced mineral composition, thereby lowering forage nutritive value. Temporal analysis showed that critical growth stages were particularly sensitive to moisture availability, influencing nutrient partitioning within the plant. While modeling approaches were employed to interpret rainfall–forage relationships and predict trends, the primary emphasis remained on understanding plant responses and improving pasture management. The findings highlight the importance of adaptive management strategies, such as optimized grazing schedules and supplemental nutrition, to mitigate the effects of climatic variability. This study contributes to sustainable livestock production by providing insights into climate–forage interactions that support improved feed quality, resource-use efficiency, and resilience of grazing systems under changing environmental conditions.