Emergence and Survival Response of Seven Grasses for Six Wet-Dry Sequences

Abstract

A greenhouse study was conducted to determine seedling emergence and survival responses of 7 warm-season grasses to 6 combinations of initial wet-day and dry-day water sequences. Two factors which affected the number of seedlings that survived the first wet-dry watering sequence following planting were: (1) the number of seedlings produced in the first wet period which developed sufficient vigor to survive the subsequent drought or dry period, and (2) the number of ungerminated but viable seeds which remain after the first wet-dry watering sequence. Sideoats grama (Bouteloua curtipendula (Michx.) Torr.) seedlings emerged within 18 h of the initial wetting, with maximum numbers occurring on days 2 and 3. There was a high seedling mortality during the dry periods. 'Cochise' lovegrass (Eragrostis lehmanniana Nees × E. trichophora Coss and Dur.), 'Catalina' Boer lovegrass (E. curvula var. conferta (Schrad.) Nees), and 'A-130' and 'SDT' blue panicgrass (Panicum antidotale Retz) emerged on day 2 or later, and maximum seedling counts occurred on days 4 to 6. 'A-68' Lehmann lovegrass (E. lehmanniana Nees) and 'A-84' Boer lovegrass did not have significant emergence until there were 3 or more consecutive wet days. Seedling mortality, during dry periods of 2 to 7 days following initial wetting, ranged from 0 to 70% of the viable seeds. Survival characteristics of the grasses were not directly affected by total water loss. There were differences within varieties of the same species, and some grasses were better suited for surviving short term droughts during early seedling stages. These studies provided information showing how the survival characteristics of plants to the first wet-dry watering sequence can be used to assist in selecting species for range revegetation.