Response of Lehmann Lovegrass to Time of Fertilizer Application

Abstract

On a desert grassland site in southern Arizona, production of Lehmann lovegrass (Eragrostis lehmanniana) was significantly increased by applications of 30-10-0 fertilizer as late as July 22. Seed yields were least with later dates of fertilization. Nitrogen and phosphorus contents of the plants were increased within 1 week after application; thereafter they generally declined. Nitrate-nitrogen and available phosphate in the surface 4 inches of soil increased immediately after fertilization, and the nitrate-nitrogen then decreased rapidly. Plots fertilized at later dates generally reached their peak yield and higher nitrogen and phosphorus contents later and remained greener into the fall months than those fertilized at the beginning of the rainy season. Herbage growth of forbs the following spring was greater on fertilized plots than on control plots, but data were very variable and not significant. No residual response of Lehmann lovegrass was found the second summer growing season after fertilization, probably a result of the dry summer.