Germination requirements of Arizona native perennial grasses and their establishment in existing stands of Eragrostis lehmanniana Nees

Abstract

Germination of 10 native and exotic grasses was compared for temperature regimes representing abruptly and gradually fluctuating minimum and maximum wet seedbed temperatures in summer, spring, and winter, respectively, in the desert grassland. Gradually fluctuating temperatures produced similar total percent germination but more rapid germination than abruptly alternating temperatures and constant 25 degrees C. Lehmann lovegrass (Eragrostis lehmanniana) and 7 native grasses were sown into stands of Lehmann lovegrass that were left intact, burned, sprayed with herbicide and left standing, or sprayed and mowed. In 1992 mow and dead standing treatments reduced Lehmann lovegrass seedling density and improved establishment of cane beardgrass (Bothriochloa barbinodis), Arizona cottontop (Digitaria californica), green sprangletop (Leptochloa dubia), and plains bristlegrass (Setaria leucopila) compared to burn and control treatments. In 1993 the burn treatment reduced mature Lehmann lovegrass and enhanced establishment of sideoats grama (Bouteloua curtipendula), Arizona cottontop, green sprangletop, and plains bristlegrass compared to the other treatments.