Date of this Version
The degeneration of native bluestem prairies of eastern Nebraska occurs slowly under moderate grazing or slight overgrazing but within two to five years where overgrazing is pronounced. Although the changes in the plant populations are continuous until the soil is finally almost bare, for convenience of study they have been grouped into several more or less distinct stages (Weaver and Harmon, 1935). An intermediate stage in deterioration is indicated by a great increase in the abundance of bluegrass (Poa pratensis), blue grama grass (Bouteloua gracilis), or buffalo grass (Buchloe dactyloides), the latter especially on low ground. Under long continued grazing and trampling, the native bluestems and most other prairie grasses disappear. This stage is characteristic of the bluegrass or short-grass pastures or a mixture of these. The purposes of this investigation were to ascertain the decrease in yield accompanying close grazing of virgin prairie, and to determine the relative yields of various types of prairie and of native pastures which replace them.