Observational evidence for groundwater influence on crop yields in the United States.

Autor:	Deines JM; Department of Earth System Science, Center on Food Security and the Environment, Stanford University, Stanford, CA 94305.; Earth Systems Predictability and Resiliency Group, Pacific Northwest National Laboratory, Richland, WA 99354., Archontoulis SV; Department of Agronomy, Iowa State University, Ames, IA 50011., Huber I; Department of Agronomy, Iowa State University, Ames, IA 50011., Lobell DB; Department of Earth System Science, Center on Food Security and the Environment, Stanford University, Stanford, CA 94305.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2024 Sep 03; Vol. 121 (36), pp. e2400085121. Date of Electronic Publication: 2024 Aug 26.
DOI:	10.1073/pnas.2400085121
Abstrakt:	As climate change shifts crop exposure to dry and wet extremes, a better understanding of factors governing crop response is needed. Recent studies identified shallow groundwater-groundwater within or near the crop rooting zone-as influential, yet existing evidence is largely based on theoretical crop model simulations, indirect or static groundwater data, or small-scale field studies. Here, we use observational satellite yield data and dynamic water table simulations from 1999 to 2018 to provide field-scale evidence for shallow groundwater effects on maize yields across the United States Corn Belt. We identify three lines of evidence supporting groundwater influence: 1) crop model simulations better match observed yields after improvements in groundwater representation; 2) machine learning analysis of observed yields and modeled groundwater levels reveals a subsidy zone between 1.1 and 2.5 m depths, with yield penalties at shallower depths and no effect at deeper depths; and 3) locations with groundwater typically in the subsidy zone display higher yield stability across time. We estimate an average 3.4% yield increase when groundwater levels are at optimum depth, and this effect roughly doubles in dry conditions. Groundwater yield subsidies occur ~35% of years on average across locations, with 75% of the region benefitting in at least 10% of years. Overall, we estimate that groundwater-yield interactions had a net monetary contribution of approximately $10 billion from 1999 to 2018. This study provides empirical evidence for region-wide groundwater yield impacts and further underlines the need for better quantification of groundwater levels and their dynamic responses to short- and long-term weather conditions. Competing Interests: Competing interests statement:The authors declare no competing interest.
Databáze:	MEDLINE
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