Expanded Potential Growing Region and Yield Increase for Agave americana with Future Climate

Sarah C Davis,John T Abatzoglou,David S Lebauer

doi:10.3390/agronomy11112109

Sarah C Davis, John T Abatzoglou + Show 1 more

Open Access

https://doi.org/10.3390/agronomy11112109

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Journal: Agronomy	Publication Date: Oct 21, 2021
Citations: 6	License type: CC BY 4.0

Affiliation: University of California, Merced, University of Arizona

Abstract

Rising crop risk for farmers and greater subsidy costs for governments are both associated with changing climatic conditions, including increased water scarcity. The resilience of Agave spp. in both hot and dry conditions, combined with their wide range of uses, position these plants as novel high-yielding crops suitable for both (i) a warming climate and (ii) agricultural regions with finite water resources. A simple model of the physiological response of Agave americana to variations in solar radiation, temperature, and precipitation was used to predict A. americana yields globally at a 4 km spatial resolution for both contemporary climate and high-end warming scenarios. The potential growing region for A. americana expanded by 3–5% (up to 3 million ha) and potential biomass production increased by 4–5% (up to 4 Gt of additional biomass) with climate warming scenarios. There were some declines in biomass with the climate warming projected in smaller dispersed locations of tropical South America, Africa, and Australia. The amount of water required for optimal A. americana yield is less than half of the current water required for other crops grown in semi-arid agricultural regions of the southwestern US, and a similar low water demand can be expected in other semi-arid regions of the world. Rock mulching can further reduce the need for irrigation and increase suitable cropland area for A. americana by 26–30%. We show that >10 Mg ha−1 y−1 of A. americana biomass could be produced on 27 million ha of cropland without requiring irrigation. Our results suggest that cultivation of A. americana can support resilient agriculture in a future with rising temperatures and water scarcity.

Highlights

Agave americana L., a novel crop species with very high water use efficiency (WUE), can produce dry biomass yields of 9.3 Mg ha−1 y−1 in semi-arid conditions with less than 600 mm of annual water inputs [1]
Despite the high potential for crassulacean acid metabolism (CAM) crops to impart resilience in agroecosystems [5], there is a gap in the current understanding about potential growing locations for novel CAM crops like A. americana in dry conditions
A simple model of the physiological response of A. americana to variations in solar radiation, temperature, and precipitation was recently developed [21] based on the environmental productivity index (EPI) that was first described as a predictive modeling tool for CAM plants by Park Nobel [22,23]

Summary

Introduction

Agave americana L., a novel crop species with very high water use efficiency (WUE), can produce dry biomass yields of 9.3 Mg ha−1 y−1 in semi-arid conditions with less than 600 mm of annual water inputs [1]. Stomata open during the night when temperatures are cooler and humidity is higher, which prevents the water loss that would otherwise occur during hot days. This physiological adaptation may serve as an increasingly beneficial trait as temperatures increase and droughts intensify with climate change. Despite the high potential for CAM crops to impart resilience in agroecosystems [5], there is a gap in the current understanding about potential growing locations for novel CAM crops like A. americana in dry conditions. While some Agave spp. are already commercially cultivated, A. americana has cold tolerance that makes it well-suited to conditions at more temperate latitudes [1,5]

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