Expanded Potential Growing Region and Yield Increase for <i>Agave americana</i> with Future Climate

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.

Keywords

• water use efficiency
• agriculture
• resilience
• crop production
• CAM
• arid