Water Savings of Crop Redistribution in the United States

Abstract

Demographic growth, changes in diet, and reliance on first-generation biofuels are increasing the human demand for agricultural products, thereby enhancing the human pressure on global freshwater resources. Recent research on the food-water nexus has highlighted how some major agricultural regions of the world lack the water resources required to sustain current growth trends in crop production. To meet the increasing need for agricultural commodities with limited water resources, the water use efficiency of the agricultural sector must be improved. In this regard, recent work indicates that the often overlooked strategy of changing the crop distribution within presently cultivated areas offers promise. Here we investigate the extent to which water in the United States could be saved while improving yields simply by replacing the existing crops with more suitable ones. We propose crop replacement criteria that achieve this goal while preserving crop diversity, economic value, nitrogen fixation, and food protein production. We find that in the United States, these criteria would greatly improve calorie (+46%) and protein (+34%) production and economic value (+208%), with 5% water savings with respect to the present crop distribution. Interestingly, greater water savings could be achieved in water-stressed agricultural regions of the US such as California (56% water savings), and other western states.

Spatiotemporal Patterns of Crop Irrigation Water Requirements in the Heihe River Basin, China

“…At the same time, however, results show that IWR c values for corn were significantly higher than those for the other major crops; thus, a rapid expansion in the area of cultivated corn would only serve to intensify the water supply imbalance [44]. We argue that a continuous increase in the area of cultivated corn is not feasible; rather, it is crucial to minimize the cultivation of water-intensive crops and the expansion of cultivated land, emphasizing instead the husbandry of plants that require less water [45,58,59]. …”

The Global Food‐Energy‐Water Nexus

“…This analysis (Falkenmark & Rockström, ) did not entirely account for the increasing water demand associated with dietary transitions or growing biofuel demand. Nevertheless, it stressed the important constraints placed by water resources on global food security and the need for approaches that conserve water or use it more efficiently (Davis, Rulli, Garrassino, et al, ; Davis, Rulli, Seveso, et al, ; Davis, Seveso, et al, ; Jägermeyr et al, ; MacDonald et al, ) instead of increasing human appropriation of water resources by expanding agriculture (i.e., green water use) or increasing withdrawals for irrigation (i.e., blue water use).…”

“…Likewise, it is possible to use different irrigation and soil management strategies to close the crop yield gap by one half without increasing cropland area or irrigation use (Jägermeyr et al, ). Other work showed that, by redistributing crops on the basis of their suitability, it is possible for the United States to realize a modest water savings (5%) and improve calorie (+46%) and protein (+34%) production without adversely impacting feed production, crop diversity, or economic value (Davis, Seveso, et al, ). Similarly, recent research investigating global scenarios of crop redistribution to minimize irrigation water consumption has shown that it is possible to increase food production and feed an additional 825 million people while reducing irrigation water consumption by 12% without losing crop diversity or expanding the cultivated area (Davis, Rulli, Seveso, & D'Odorico, ).…”

Advancing Water Footprint Assessment Research: Challenges in Monitoring Progress towards Sustainable Development Goal 6

“…Thirteen of the fourteen papers in this special issue consider green and blue WFs [14][15][16][17][18][19][20][21][22][23][24][25][26], while eight papers include grey WF estimation. All papers that include the grey WF specifically focus on pollution through nitrogen [14,15,17,19,21,22,25,27].…”

“…Davis et al [24] study the option of increasing water-use efficiency through changing the spatial crop production pattern. They analyze, for the case of the United States, how consumptive water footprints can be reduced by changing where what crops are grown while making sure that current levels of calorie and protein production and income are maintained, and while staying within the currently cultivated land.…”