Emergence and cool-season growth of Lehmann lovegrass and Arizona cottontop on different soils

Abstract

Lehmann lovegrass (Eragrostis lehmanniana Nees.), a perennial bunchgrass, has established itself well since its introduction from South Africa. Arizona cottontop (Digitaria californica (Benth.) Henr.) is a native perennial bunchgrass that sometimes appears on the same sites and soils as Lehmann lovegrass. In a greenhouse, emergence was evaluated using line-source irrigation which simulated natural summer precipitation on two soil types collected from the Santa Rita Experimental Range (SRER). Density and cool-season growth of each species were monitored along transects located at the SRER on three different soils. I found that although Lehmann lovegrass and Arizona cottontop emerge similarly on two soils, Arizona cottontop un-emerged caryopses had a better percent survival rate. Also, Lehmann lovegrass plants had more green above-ground biomass from November to May than Arizona cottontop, and Lehmann lovegrass was able to greenup more rapidly following rain. This study showed these species have similar emergence characteristics, but that their cool-season greening differs.