Hydrothermal Germination Models: Improving Experimental Efficiency by Limiting Data Collection to the Relevant Hydrothermal Range. Issue 5 (10th August 2017) - Hardegree, Stuart P.
Abstract : Hydrothermal models used to predict germination response in the field are usually parameterized with data from laboratory experiments that examine the full range of germination response to temperature ( T ) and water potential (ψ). Inclusion of low‐ψ and high‐ and low‐ T treatments, however, may not be necessary if their contribution to germination rate in the field is negligible. In this study, we simulated cumulative germination response of 13 range grass seedlots to a typical seasonal planting scenario used for rangeland restoration in the Great Basin region of the western United States. Given realistic estimates of actual time spent within the full hydrothermal range of these seedlots, >95% of germination response in the field could be predicted by models that only considered germination at ψ values less negative than −0.5 MPa and T values <25°C. Limiting laboratory treatments to a restricted hydrothermal range could greatly increase the efficiency of parameterizing hydrothermal models for predicting field response. Laboratory expenditures in this example could be reduced by 80 to 90% with only a relatively small reduction in the potential accuracy of field predictions.