Evaluating opportunities for an increased role of winter crops as adaptation to climate change in dryland cropping systems of the U.S. Inland Pacific Northwest

Claudio O Stöckle,Stewart Higgins,Tina Karimi,Erin Brooks,John Abatzoglou,John Antle,Roger Nelson,Dave Huggins,Sanford D Eigenbrode,William Pan

doi:10.1007/s10584-017-1950-z

Abstract

The long-term sustainability of wheat-based dryland cropping systems in the Inland Pacific Northwest (IPNW) of the United States depends on how these systems adapt to climate change. Climate models project warming with slight increases in winter precipitation but drier summers for the IPNW. These conditions combined with elevated atmospheric CO2, which promote crop growth and improve transpiration-use efficiency, may be beneficial for cropping systems in the IPNW and may provide regional opportunities for agricultural diversification and intensification. Crop modeling simulation under future climatic conditions showed increased wheat productivity for the IPNW for most of the century. Water use by winter wheat was projected to decrease significantly in higher and intermediate precipitation zones and increase slightly in drier locations, but with winter crops utilizing significantly more water overall than spring crops. Crop diversification with inclusion of winter crops other than wheat is a possibility depending on agronomic and economic considerations, while substitution of winter for spring crops appeared feasible only in high precipitation areas. Increased weed pressure, higher pest populations, expanded ranges of biotic stressors, and agronomic, plant breeding, economic, technology, and other factors will influence what production systems eventually prevail under future climatic conditions in the region.

Highlights

Anthropogenic climate change in mid-to-high latitudes will lead to accelerated development and earlier maturation of crops (e.g., Cleland et al 2007)
Resultant shortened growing seasons should in principle reduce biomass production and yields; biomass of dryland crops in the Inland Pacific Northwest (IPNW) of the United States is typically limited by water rather than by length of the growing season
While many wheat varieties are used in the region, a Brepresentative^ wheat cultivar was defined for this system analysis that conformed to the typical growing season and canopy ground cover in each Agroecological Classes (AEC), characteristics that are important for determining resource capture and productivity

Summary

Introduction

Anthropogenic climate change in mid-to-high latitudes will lead to accelerated development and earlier maturation of crops (e.g., Cleland et al 2007). Elevated CO2 concentration [CO2] has two important effects on plants: (a) increased photosynthesis, biomass, and yields of C3 plants (minimal effect on C4 plants); and (b) decreased stomatal conductance (both in C3 and C4 plants), leading to reduced crop water loss (Ainsworth and Rogers 2007). The effect of [CO2] on plant growth and stomatal conductance (BCO2 fertilization^) has been demonstrated in open field experiments using Free-Air CO2 Enrichment (FACE) systems, which simulate agricultural conditions (Long et al 2004). Earlier FACE experiments (Tubiello et al 1999) demonstrated that well-watered wheat yield increased 7 to 9% when [CO2] was elevated from 350 to 550 ppm

Methods

Results

Conclusion