A New Ending to an Old Classical Stocking Rate Study
Abstract

After the Dust Bowl that gripped the Great Plains in the 1930s, researchers in several states implemented studies to determine recommended stocking rates that would sustain vegetative vigor and production. In 1946 a long-term stocking rate study was initiated to compare stocker animal production and vegetative production at light, moderate, and heavy stocking rates on western Kansas rangelands. This 20-year study showed that individual animal gains declined as stocking rate increased beyond a moderate level, and that pasture yield was inversely related to stocking rate. With increasing stocking rate, composition shifted toward low-yielding buffalograss and away from greater-yielding western wheatgrass and blue grama. However, though previously not reported, the heavy and light stocking rate treatments were continued in 1966 but were reversed in pastures from 1967 to 1971. Subsequently, after five years of the stocking reversal, the dry matter production in pastures also reversed. Following the reversal, buffalograss composition rapidly declined and western wheatgrass rapidly increased in the heavy- to light-stocked pasture. The light-stocked pasture also changed after the reversal to a heavy-stocked pasture by increasing buffalograss and decreasing western wheatgrass composition, but the change was not as drastic. The long-term repeated disturbance from stocking rate resulted in pastures being dominated by vegetation of diverging physiologic, morphologic, and canopy architectural structure. But divergent vegetative trends that developed due to long-term stocking appear to be reversible community phases that resist transition to a new ecological state. In shortgrass rangelands overutilized from heavy stocking rates, great improvements in rangeland health and productivity and shifts in plant community composition are possible within five years by simply lowering the stocking rate.


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