Effect of Types of Biosolids and Cattle Manure on Desert Grass Growth

We compared the effect of applying anaerobically produced biosolids, lime-stabilized biosolids, and cattle manure on the production of blue grama (Bouteloua gracilis [HBK] Lag. ex Steud.) and black grama (B. eriopoda [Torr.] Torr.) grown in pots with moderate soil water content. We also compared the physicochemical and bacteriological composition of these 3 amendments. All amendments produced similar increases in plant growth, despite their differences in plant nutrient concentrations, as a result of limitations in soil water. Heavy metal levels in biosolids were within the US Environmental Protection agency limits for Class A and Class B biosolids, but were higher than in manure. In contrast, pathogen levels were lower in biosolids than in manure. Application of biosolids and cattle manure increased the production of both grasses and may have equivalent effects under typical climatic and soil conditions of semiarid rangelands.