The recent decade has witnessed an increase in irrigated acreage in the southeast United States due to the shift in cropping patterns, climatic conditions, and water availability. Peanut, a major legume crop cultivated in Georgia, Southeast United States, has been a staple food in the American household. Regardless of its significant contribution to the global production of peanuts (fourth largest), studies related to local or regional scale water consumption in peanut production and its significant environmental impacts are scarce. Therefore, the present research contributes to the water footprint of peanut crops in eight counties of Georgia and its potential ecological impacts. The impact categories relative to water consumption (water depletion—green and blue water scarcity) and pesticide use (water degradation—potential freshwater ecotoxicity) using crop-specific characterization factors are estimated for the period 2007 to 2017 at the mid-point level. These impacts are transformed into damages to the area of protection in terms of ecosystem quality at the end-point level. This is the first county-wise quantification of the water footprint and its impact assessment using ISO 14046 framework in the southeast United States. The results suggest inter-county differences in water consumption of crops with higher blue water requirements than green and grey water. According to the water footprint analysis of the peanut crop conducted in this study, additional irrigation is recommended in eight Georgia counties. The mid-point level impact assessment owing to water consumption and pesticide application reveals that the potential freshwater ecotoxicity impacts at the planting and growing stages are higher for chemicals with high characterization factors regardless of lower pesticide application rates. Multiple regression analysis indicates blue water, yield, precipitation, maximum surface temperature, and growing degree days are the potential factors influencing freshwater ecotoxicity impacts. Accordingly, a possible impact pathway of freshwater ecotoxicity connecting the inventory flows and the ecosystem quality is defined. This analysis is helpful in the comparative environmental impact assessments for other major crops in Georgia and aids in water resource management decisions. The results from the study could be of great relevance to the southeast United States, as well as other regions with similar climatic zones and land use patterns. The assessment of water use impacts relative to resource availability can assist farmers in determining the timing and layout of crop planting.
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How does building healthy soils impact sustainable use of water resources in irrigated agriculture?
As blue water resources become increasingly scarce with more frequent droughts and overuse, irrigated agriculture faces significant challenges to reduce its water footprint while maintaining high levels of crop production. Building soil health has been touted as an important means of enhancing the resilience of agroecosystems to drought, mainly with a focus in rainfed systems reliant on green water through increases in infiltration and soil water storage. Yet, green water often contributes only a small fraction of the total crop water budget in irrigated agricultural regions. To scope the potential for how soil health management could impact water resources in irrigated systems, we review how soil health affects soil water flows, plant–soil–microbe interactions, and plant water capture and productive use. We assess how these effects could interact with irrigation management to help make green and blue water use more sustainable. We show how soil health management could (1) optimize green water availability (e.g., by increasing infiltration and soil water storage), (2) maximize productive water flows (e.g., by reducing evaporation and supporting crop growth), and (3) reduce blue water withdrawals (e.g., by minimizing the impacts of water stress on crop productivity). Quantifying the potential of soil health to improve water resource management will require research that focuses on outcomes for green and blue water provisioning and crop production under different irrigation and crop management strategies. Such information could be used to improve and parameterize finer scale crop, soil, and hydraulic models, which in turn must be linked with larger scale hydrologic models to address critical water-resources management questions at watershed or regional scales. While integrated soil health-water management strategies have considerable potential to conserve water—especially compared to irrigation technologies that enhance field-level water use efficiency but often increase regional water use—transitions to these strategies will depend on more than technical understanding and must include addressing interrelated structural and institutional barriers. By scoping a range of ways enhancing soil health could improve resilience to water limitations and identifying key research directions, we inform research and policy priorities aimed at adapting irrigated agriculture to an increasingly challenging future.
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- Award ID(s):
- 1824871
- NSF-PAR ID:
- 10454034
- Date Published:
- Journal Name:
- Elementa: Science of the Anthropocene
- Volume:
- 10
- Issue:
- 1
- ISSN:
- 2325-1026
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1525/elementa.2022.00043
