The study was conducted in Debrekidan basin, Debrekidan watershed Hawzen district, and eastern zone of Tigray, Northern Ethiopia, to identify bio-physical and socio-economic factors that affect forage production at watershed level and develop System dynamics modeling software (STELLA) at basin level. Individual interview, group discussions and visual observations were used to collect livestock feed resources assessment of basin. A total of 270 household and 30 quadrant sample (0.5m x 0.5m) area A total of 270 household were randomly sampled for this study interviewed and 30 quadrants samples (0.5m x 0.5m) were taken for the biomass sampling procedure. The Total simulated tropical livestock unit (TLU) was predicted per ten year 3094TLU, 3914TLU, 538 TLU,, 2223 TLU cattle, sheep, goat and equine, respectively. (cattle: 3094TLU, seep: 3914TLU, goat: 538 TLU, equine: 2223 TLU). The total area of the study area ranges 791.08 hectare and 69.2% was natural pasture and 30.8% arable land. Study total area ranges 791.08 hectare and (69.2% was natural pasture and 30.8% arable land). The total simulated feed requirement of the animal exceeds 838.58 ton per ten year Total simulated) feed requirement of animal exceeds 838.58 ton per ten year. While, the total simulated vegetation supply was 446.33 ton dry matters per ten year and total simulated dry mater gap estimated 392.25 ton dry matter per annum. Total simulated vegetation supply was 446.33 ton dry matters per ten year and total simulated dry mater gap estimated 392.25 tons of dry matter per annum. But vegetation supply and dry matter gap resulted significance difference at (p<0.05) in the study area. As a result effective and efficient planned and anticipatory adaptation strategy of forage feed sustainability was quite imperative to encourage local innovation and to reduce scarcity of forage feed supply Vegetation supply and dry matter gap resulted significance difference (p<0.05) in study. As a result, effective and efficient planned and anticipatory adaptation strategy of forage feed sustainability was quite imperative to encourage local innovation and to reduce scarcity of forage feed supply.

Keywords: Modeling, Simulation, vegetation supply, dry matter gap, correlation, relationship