Invasion of western United States rangelands by Bromus tectorum (cheatgrass) is an environmental and economic concern. To increase understanding of soil factors that affect growth and site invasibility by cheatgrass, the invasion of a Krascheninnikovia lanata (winterfat) community in the Honey Lake Valley of northeastern CA has been monitored for a 5 year period. Overall, sites invaded by cheatgrass have greater soil-solution ortho-P, and Mg+2, greater mineralization potential for NO3 -, greater phosphatase and amidase enzyme activities, and greater numbers of microbial cells than nearby non-invaded sites. Complementary greenhouse studies indicate that non-invaded soil is inhibitory to the growth of cheatgrass; aboveground mass was [...]
