RESPONSE TO CUTTING AND HERBICIDE TREATMENT OF MEXICAN NEEDLEGRASS (Amelichloa clandestina) IN NORTHEASTERN MEXICO

Rangelands cover a large area of Mexico. The overgrazing of these grasslands favors the invasion of Mexican needlegrass (Amelichloa clandestina). The objective was to determine the impact of cutting and glyphosate application as means to control A. clandestina in northeastern Mexico. Two sites with dominance of A. clandestina were used. The treatments were; cutting of this grass (T1), herbicide application (glyphosate; T2), and control (T3 = undisturbed plots). A completely randomized design was used, with three replicates. The lowest production of this grass was in the first cut in summer with 449 kg DM ha-1 for site one and in site two in the seventh cut in spring with 496 kg DM ha-1. Regardless of sampling date, treatments T2 and T3 registered the lowest biomass production, with 534 and 583 kg DM ha-1, on average, compared to T1 for site one. For site two, T1 and T2 presented the lowest phytomass production with 529 and 578 kg DM ha-1 and the highest was registered in T1 with 720 kg DM ha-1. The lowest values for intercepted solar radiation, height, density, and diameter of the crown were found in T2. In conclusion, leaving the species undisturbed and applying a herbicide has more effect on the predominance of Mexican needlegrass (Amelichloa clandestina) than cutting it, however, the biomass production was diminished when herbicide was applied.