Browsing Journal of Range Management, Volume 47, Number 5 (September 1994) by Subjects
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Technical Note: Mechanical despining of plains pricklypearPlains pricklypear cactus (Opuntia polyacantha L.) is abundant on the Central Great Plains, producing dry matter yields from 1,500 to 2,000 kg/ha. Although pricklypear is high in energy and palatable, long sharp spines make it, and vegetation immediately surrounding it, unavailable to livestock. The possibility of simultaneously controlling and feeding plains pricklypear led to development of machinery for harvesting and despining cactus. The mechanical despiner described here adequately removed spines from pads during periods of low relative humidity. Softening of cactus spines due to high relative humidity resulted in failure of the despiner to adequately remove spines. Cattle readily ate despined cactus in the winter when green forage was unavailable.
Water balance in pure stand of Lehmann lovegrassLehmann lovegrass (Eragrostis lehmanniana Nees), an introduced warm season grass, has invaded grasslands in southern Arizona, in many areas replacing the native warm-season grasses. A water balance evaluation in a pure stand of Lehmann lovegrass showed that more soil water was used through evapotranspiration than occurred as precipitation during 2 years of a 3-year study period. During the winter season, an appreciable amount of water was used by Lehmann lovegrass or lost by evaporation from the soil surface. The remaining available soil water was used in the spring dry period. In the dry early spring the soil water contents (to depths of 120 cm) were less than the traditional wilting point tension of -1.5 MPa. The invasion of Lehmann lovegrass into grasslands of southern Arizona is partially related to its ability to utilize soil water during parts of the year when the native species are dormant and also to extract water from the soil profile to very low water contents.