Projections of spring wheat growth in Alaska: Opportunity and adaptations in a changing climate

Abstract

Recent accelerations of climate warmings can open agricultural opportunities in the region of Interior Alaska. In this paper, a simulation of spring wheat growth forced with projected climate scenarios was conducted by the Decision Support System for Agrotechnology Transfer (DSSAT) crop model. The model was calibrated and validated using experimental data.Using an Alaskan cultivar (cv.) Ingal and a baseline covering 1989–2018, projected changes in days to maturity and yield were simulated following the Representative Concentration Pathways (RCP) 4.5 (medium–low emissions) and RCP8.5 (high emissions) climate change scenarios. For each RCP scenario, spring wheat growth was simulated in the time series covering 2020–2049 (indicated as 2035 s), 2050–2079 (2065 s), and 2080–2099 (2090 s). The baseline value of days to maturity was 69 and yield resulted in 1956 kg ha−1. Results show that under RCP4.5 and RCP8.5 2035 s, 2065 s, and 2090 s scenarios, days to maturity decrease, ranging from 64 to 55 days, and changes in yield range from a 3% increase to a 6% decrease.Adaptation by increasing the cultivar’s growing degree day requirement resulted in 69 and 68 days to maturity in RCP4.5 2035 s and RCP8.5 2035 s, respectively, which in turn increased yields 5% and 7%, respectively. Increased soil water at planting from 80 to 85% field capacity, due to increased annual precipitation, resulted in additional yield increases. This indicates that selecting spring wheat varieties to maintain similar baseline days to maturity and agronomic practices that store fall/winter precipitation are of importance to materialize future spring wheat yield increases of Interior Alaska.

Keywords

• Agriculture
• Spring wheat
• Climate change
• Alaska
• Crop model
• Projections