The Great Plains Corridor rangeland project at Texas A&M University aims to use natural vegetation systems as phenological indicators to monitor seasonal development and climatic effects on regional growth conditions. The study employs ERTS-1 MSS data to quantitatively measure vegetation conditions over broad regions. Radiance values from spectral bands 5 and 7 are used to compute a Band Ratio Parameter (BRP), which is correlated with aboveground green biomass and vegetation moisture content. The project involves a network of ten test sites across six states, from south Texas to North Dakota, with ground observations recorded every eighteen days. The BRP, transformed into a Transformed Vegetation Index (TVI), shows strong correlation with vegetation conditions, particularly at the Throckmorton test site. The study confirms the feasibility of using ERTS-type data for regional rangeland management and agricultural operations, highlighting the potential for monitoring vegetation conditions and supporting decision-making by farm and ranch owners.The Great Plains Corridor rangeland project at Texas A&M University aims to use natural vegetation systems as phenological indicators to monitor seasonal development and climatic effects on regional growth conditions. The study employs ERTS-1 MSS data to quantitatively measure vegetation conditions over broad regions. Radiance values from spectral bands 5 and 7 are used to compute a Band Ratio Parameter (BRP), which is correlated with aboveground green biomass and vegetation moisture content. The project involves a network of ten test sites across six states, from south Texas to North Dakota, with ground observations recorded every eighteen days. The BRP, transformed into a Transformed Vegetation Index (TVI), shows strong correlation with vegetation conditions, particularly at the Throckmorton test site. The study confirms the feasibility of using ERTS-type data for regional rangeland management and agricultural operations, highlighting the potential for monitoring vegetation conditions and supporting decision-making by farm and ranch owners.