Forage and seed production of blue grama rangeland can be increased by chemically thinning the native grass stand. Thinning of native blue grama range was accomplished by spraying strips 30 cm wide with glyphosate [N-(phosphonomethyl) glycine] and leaving alternating 15 cm wide strips of undisturbed vegetation. This reduced the stand to one-third of its original ground cover. Forage production was increased an average of 37% over the untreated pastures during a 7-year period. Plants in the thinned area were taller and had a more upright growth form which made the herbage more readily available to livestock. When plants were grazed during the winter, 67% more animal days of grazing were obtained from the thinned pastures than from the untreated pastures. For the 5 years when seed was harvested, production of clean seed averaged 5.6 kgf ha on the untreated pastures and 13.0 kg/ha on the thinned pastures. In northern Wyoming, Rauzi (1980) reported that spraying strips of native range 36 cm wide with a heavy rate of atrazine [2-chloro-4-ethylamino-6-isopropyl amino-l ,3,Striazine] and leaving alternating bands of undisturbed vegetation 20 cm wide increased blue grama (Boutelouu gracilis) forage production. Production of blue grama during the first 5 years following treatment averaged 168% more than the untreated pastures and in the eleventh year was still 43% more. In a study that evaluated the effects of growing space on individual plants of blue grama, as space per plant increased, the height of seed stalks, number of seed stalks per plant, and weight per plant increased (McGinnies 1971). Those plants with the most growing space had a more upright growth form than those with less growing space. When growing space was reduced to only 81 cm2 per plant, there was no mortality even in drought years, which indicated that blue grama can persist when severely crowded. It was assumed that if a dense stand of native blue grama range could be thinned so that the remaining plants had more growing space and thus more water available, it might be possible to increase plant height and seed yield. Increasing plant height would make the forage more readily available to grazing livestock. Taller stems would also make seed easier to harvest with a combine. In a preliminary small-plot study (unpublished) native blue