Predicting germination in semi-arid wildland seedbeds II. Field validation of wet thermal-time models

Abstract

Accurate prediction of germination for species used for semi-arid land revegetation would support selection of plant materials for specific climatic conditions and sites. Wet thermal-time models predict germination time by summing progress toward germination subpopulation percentages as a function of temperature across intermittent wet periods or within singular wet periods. Wet periods may be defined by any reasonable seedbed water potential above which seeds are expected to imbibe sufficiently to germinate. These models may be especially applicable to the Artemisia steppe of the western U.S.A. where water availability limits germination in summer and early fall while cool temperatures limit germination in late fall, winter, and spring when soil water is available. To test accuracy of wet thermal-time models we placed seedbags with seeds of five species commonly used in wildland revegetation, as well as two collections of the invasive annual grass, Bromus tectorum L. into Artemisia tridentata Nutt. ssp. wyomingensis Beetle and Young zone seedbeds for 19 field incubation periods over four seasons.

Citation

Rawlins, Jennifer K.; Roundy, Bruce A.; Eggett, Dennis; Cline, Nathan. 2011. Predicting germination in semi-arid wildland seedbeds II. Field validation of wet thermal-time models. Environmental and Experimental Botany. 76: 68-73.