The world is facing a balancing act: working to feed more than 9 billion people by 2050 while being good stewards of our limited natural resources. To achieve this balance, we must understand how our water is allocated and how well we are using it. To date, there hasn't been a standard methodology for measuring water use in crops, livestock or ethanol production. DWFI is working on a series of "living" reports that provide water productivity insights for important food-producing regions of the world. To begin with, we looked at data in our own backyard.
Nebraska is a national leader in agricultural production, which contributed about $23 billion to the state's economy in 2016. The state is the nation's third largest producer of corn and second largest in cattle production. It is also the second largest producer of ethanol and distillers' grains (DGs). Corn is a major input in the ethanol industry, which uses it for fuel production. DGs, a by-product of ethanol production, are used as livestock feed, forming what the Nebraska Corn Board refers to as "Nebraska's Golden Triangle:" corn, ethanol and livestock.
Irrigation plays a vital role in Nebraska's agricultural prominence. The state ranks first in the nation in total irrigated cropped area with 3.4 million hectares. The expansion of irrigated agriculture has intensified competition for limited water resources, which is why measuring - and improving - WP is so important.
Nebraska has one of the most highly productive cropping systems in the country and world. Over the last 25 years, the state's corn and soybean yields have grown considerably. This significant increase in grain yields, combined with the adoption of improved farm-level management, advanced irrigation systems and regulatory limits on irrigation pumping, has helped sustainably improve the WP of crop production in the state. From 1990 to 2014, the WP of soybeans and corn increased by 79% and 71%, respectively, while groundwater levels have largely stabilized.
The irrigation application rate in the three NRDs studied (Central Platte, Lower Niobrara and Tri-Basin) has dropped by 20% on average for cornfields and by 8% for soybean fields between 2004 and 2013. When applied irrigation is reduced, farmers benefit in the form of lower pumping costs and less leaching of fertilizer and chemicals.
The livestock sector is an important part of Nebraska's economy as well, contributing about 54% of the total economic value of the state's agricultural sector in 2016. Livestock production has increased considerably in the last few decades, matched by a large increase in livestock productivity, which has helped to minimize the rate of increase in livestock feed requirements. The use of the DGs as livestock feed improves the WP of livestock products and reduces pressure on freshwater resources.
The issue with livestock is how to further increase and sustain higher WP. Unlike the studied crops, livestock products lack standard benchmarks that could be used as a yardstick to measure progress in WP. Therefore, potential future research areas in the livestock sector include setting benchmarks, estimating WP gaps and identifying the critical factors affecting consumptive water use for livestock.
The study revealed that, despite tremendous improvement in agricultural WP, the water footprint of biofuels is considerably larger than that of fossil fuels, a factor policymakers should consider when developing biofuel policies.
The current study does confirm earlier findings that bioethanol from corn generates more energy than is required for production. Bioethanol from corn contains 2.1 times more energy for every unit of fossil fuel input. It also reduces the GHG emission by 53% compared to gasoline.
Nebraska is leading the way in precision water management for agriculture and livestock productivity. Great strides have been made in improving WP, but there is room for continued improvement. The Nebraska Water Productivity Report is an excellent benchmark for future research and sets the standard for global WP efforts.