Twenty Years of Changes in Grass Production following Mesquite Control and Reseeding

Cable, Dwight

Production of native perennial grasses and seeded Lehmann lovegrass was measured periodically for 21 years on a semidesert area where velvet mesquite was controlled by 2,4,5-T aerial spray and on an adjacent unsprayed area to determine how mesquite control would affect grass produciton and how long the effect would last. Grass production on the sprayed area increased dramatically during the first 5 years in a time-dependent relationship in response to the higher levels of available soil moisture. During the last 12 years, changes in lovegrass production were associated with changes in summer rainfall of the current and previous summers and of the intervening winter (2 separate variables). Because of the strong competition from lovegrass, native grass production during the last 12 years did not show its usual relationship with summer rainfall, but decreased gradually and consistantly on both the sprayed and unsprayed areas. At the end of the study period, native grasses provided only 10% of the total perennial grass production on the sprayed area and 20% on the unsprayed. Increased grass production, resulting from the mesquite control treatment and seeding, paid for the treatment within 4 years, and the sprayed area was still producing more grass than the unsprayed area 20 years later.

Twenty Years of Changes in Grass Production following Mesquite Control and Reseeding

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