La Contribución Del Zacate Liebrero (Bouteloua Barbata Var. Rothrockii) A La Producción De Forraje En El Matorral Arbosufrutescente Del Centro De Sonora

Rothrock's Grama (Bouteloua barbata var. rothrockii) is a perennial, native plant that is an important component of the vegetation in the Sonoran Desert, however there is not much information indicating the possible contribution of the grass to the diet of animals. The study was carried out in three ranches in the center of Sonora to evaluate the productive characteristics of the species and its possible contribution to the diet of animals. Three scenarios were considered: 1) 80% of the total forage produced by Rothrock´s grama during the year is used to feed livestock and wildlife, 2) It is considered that only 27% of the forage produced by the plant is used during the spring of according to previous studies, and 3) It is considered that only 10.25% of the forage produced by the plant during the summer is used. The results show that the contribution of Rothrock’s grama during a year of excellent rainfall and considering 80% utilization varies from 556 to 756 kg of DM/ha. The stocking rate with these values varies from 6.5 to 8.9 ha/AU/year and the economic contribution in pesos varies between $492.1 and $673.8 pesos per hectare. In the second scenario, where the hare grass contributes 27% of the diet, the production of available dry forage varies from 187.65 to 255.15 kg of DM/ha. The stocking rate with these values varies from 19.31 to 26.26 ha/U.A./year and the economic contribution of the pasture varies between $166.8 and $226.82 pesos per hectare. In the third scenario where the grass contributes 10.25% of the diet, the production of available dry forage varies from 71.23 to 96.86 kg of DM/ha. The stocking rate with these values varies from 50.87 to 69.17 ha/U.A./year and the economic contribution of the pasture varies between $63.32 and $86.10 pesos per hectare. This is probably the most realistic scenario on ranches when precipitation is normal or well below average. It is concluded that the quantity of dry matter produced by Rothrock’s grama plants during the study year was high because of the extraordinary rainfall received and varies from 695 to 945 kg of dry matter per hectare. The economic contribution of grass to livestock is influenced by the amount and distribution of rainfall and can fluctuate among sites and years between $492.1 and $673.8 to $63.32 and $86.10 pesos per hectare.