Hand-Grubbing Mesquite in the Semidesert Grassland

Abstract

Honey mesquite (Prosopis juliflora var. glandulosa Torr.) has become an ever-increasing problem on the semidesert grassland. The semidesert grassland occupies an extensive area in southeastern Arizona, southern New Mexico, western Texas, and northern Mexico. On the Jornada Experimental Range in southern New Mexico, mesquite domipated land has increased from 13 percent of the total in 1915 to 36 percent of the total in 1946 and 49 percent in 1957. This has occurred on land that has a history of conservative grazing use and even on some large areas under complete protection. While heavy grazing use will accelerate the spread of mesquite, the complete absence of grazing use will not prevent that spread. Mesquite invasion on the sandy soils of the area is characterized by: (1) young plants that are hidden among the grasses, (2) older mesquite plants with sand blow-outs around them, and (3) the disastrous mesquite sand dunes. Once mesquite invasion has reached the third stage, it is uneconomical by present standards to reclaim that land. The average carrying capacity of the range during normal years is reduced from 18 animal-unit-years of grazing per section in the first stage to 3 animal-unit-years or less of grazing per section in the third stage. Grubbing light stands of young mesquite plants is the most economical means of controlling mesquite. When plants become too large to grub, more expensive chemical control measures must be employed. In handgrubbing care must be exercised to completely sever the plant below the budding area of the root. In plants not having sand piled around the base, the budding area is found about four inches below the surface of the ground.