The population of the microbial flora of a mixed blue gramma grass (Bouteloua gracilis H. B. K.) and prickly pear (Opuntia polyacantha Haw.) prairie near Amarillo, Texas, was studied during 1971 after a severe drought. Bacteria, fungi, and algae were estimated by plate count and terminal dilution procedures. Rates of grass and paper decomposition were determined. The microbial flora of soil associated with bovine-grazed grass did not differ significantly from the flora associated with ungrazed grass, either qualitatively or quantitatively. During drought, a greater number of fungi were found in soil associated with prickly pear than in that associated with blue gramma grass. The microbial biomass decreased one full log between the surface and a depth of 50 cm, and the percentage of anaerobes increased with depth. The maximum numbers of fungi and algae detected were 8 × 105 and 6 × 104/g respectively. A linear relationship existed between the microbial biomass and soil moisture. The maximum number of aerobic, heterotrophic bacteria detected was 1.5 × 108 viable cells per g of soil.
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机译：得克萨斯州阿马里洛附近的混合蓝头草（Bouteloua gracilis H. B. K.）和花梨（Opuntia polyacantha Haw。）草原的微生物菌群在严重干旱后于1971年进行了研究。细菌，真菌和藻类通过平板计数和终末稀释程序估算。确定草和纸的分解速率。无论是定性还是定量，与牛毛草相关的土壤微生物区系与未牛毛草相关的微生物区系均无显着差异。在干旱期间，与刺梨相关的土壤中发现的真菌数量多于与蓝革草相关的真菌。微生物生物量在表面和50 cm深度之间减少了一个完整的对数，并且厌氧菌的百分比随深度增加。检出的真菌和藻类的最大数量分别为8×10 5 和6×10 4 / g。微生物量与土壤水分之间存在线性关系。每克土壤中检出的需氧异养细菌的最大数量为1.5×10 8 活细胞。
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