With agriculture increasingly on the hook to improve water quality, curb erosion, and meet other environmental goals, it only makes sense to target soil and water conservation practices to the places on the landscape where they'll do the most good. Exactly how to achieve this is the catch, but a promising new solution is now at the ready, thanks to research led by the USDA-Agricultural Research Service (USDA-ARS) and Environmental Defense Fund.
Writing in the current issue of the Journal of Environmental Quality, the team describes its Agricultural Conservation Planning Framework (ACPF): a systematic approach to identifying the best options for reducing nutrient losses and erosion within a watershed--whether those opportunities exist in farm fields, along stream banks, or in other locations.
This image shows conservation planning in a watershed conceptualized as a pyramid. At the base are fundamental practices to improve soil health, such as crop rotations. These practices are then built upon by techniques that control water flows and nutrient losses within fields, outside of (below) fields, and finally along stream corridors (riparian management).
Figure courtesy of Tomer, M.D, et al. 2013. Combining precision conservation technologies into a flexible framework to facilitate agricultural watershed planning. J. Soil Water Conserv. 68(5):113A-120A, doi:10.2489/jswc.68.5.113A.
Its roots lie in "precision conservation," the idea of selecting the right conservation practice and placing it where it will be most effective, says lead author Mark Tomer, a USDA-ARS scientist in Iowa. However, while most attempts at this focus on one practice at a time, the ACPF looks at several.
The result is an entire inventory of conservation possibilities, from which farmers and other stakeholders within a watershed can choose their preferred options and even map out a strategy together.
That's important, because as water quality continues to decline in Lake Erie, the Gulf of Mexico, and other locations, people are realizing the need both for a mix of practices and a concerted push.
"These problems are continental in scope, but addressing them involves the management of thousands of small agricultural watersheds and millions of individual farm fields," Tomer says. "So I think providing for a coordinated effort among farmers and others to address water quality is really key."
Building the framework
Excess nutrients flowing from agricultural watersheds affect water quality in several ways. Nitrogen and phosphorus contribute to algal blooms and areas of oxygen-starved, or "hypoxic," zones in downstream water bodies. High nitrate levels also make water unfit for drinking.
But the measures farmers can take to address these problems aren't always apparent. Moreover, while most farmers already engage in conservation, says Tomer, they often only target the most obvious problems on their own lands, such as erosion.
To build on those individual efforts, Tomer and the team began their research in 2012 by creating criteria for siting conservation practices in a suite of optimal locations within a watershed. The criteria are based on information like soil type and land use, and the presence of tile drainage. But what really makes them possible are extremely detailed, topographic maps derived from LiDAR surveys of the ground surface. So fine is the resolution, says Tomer, the technology even allows the height of stream banks to be estimated.
While producing the siting criteria was a critical step, however, the group soon realized this wasn't terribly useful on its own. "We ended up with a list of practices with no flow or overarching concept to guide decisions about their use," Tomer says. That's where the framework comes in.
The framework is basically a pyramid, he explains, with cover crops and other crucial soil management practices at its base. The next level up focuses on options for curbing runoff and nutrient losses within farm fields: Which fields, for example, are most suited to controlled drainage systems or grassed waterways?
Next, the ACPF pinpoints the prime spots for conservation practices outside of fields (nutrient removal wetlands, for instance). And, lastly, it identifies the prospects for reducing both surface and subsurface losses of nutrients and sediments along stream and river corridors.
"So you can think of it as a continuum of opportunities," Tomer says, starting with essential soil health practices that every farmer wants to use, and moving up to more specialized--and, sometimes, more expensive--technologies that should be installed only where they'll give the most benefit.
Impacts on production
Something else users can calculate is how much cropland will need to come out of production to make way for conservation installations. In the work in JEQ, the researchers sited locations for four practices in two test watersheds in Iowa and Illinois, creating different combinations of the techniques across the landscape, called scenarios. For each scenario, they then asked how many farm acres would have to be sacrificed to meet their chosen water quality target: the Iowa Nutrient Reduction Strategy goal of a 40% drop in nitrogen.
In both watersheds they found the target could be feasibly met at the expense of just 3-4% of total cropland. Plus, the ACPF asks whether practices can be placed in sequence, taking the pressure off any single approach to improve water quality. "So if you've got several different practices, they're well-distributed around the watershed, and they don't take a lot of land out of production, you should have something farmers can live with," Tomer says.
At the same time, the ACPF results are never prescriptive, he adds. Instead, they're meant to spark discussion and collaboration. "I think the most important thing about this," he says, "is that it's a way to help farmers understand their options."
The research was funded in part by a USDA-NRCS Conservation Innovation Grant to the Environmental Defense Fund. The ACPF has been developed into an ArcGIS toolbox that will be publicly available on the North Central Region Water Network's website this fall.
View the two open access JEQ papers describing the ACPF:
Journal of Environmental Quality doi:10.2134/jeq2014.09.0386
Susan V. Fisk | EurekAlert!
Back to Nature: Palm oil plantations are being turned back into protected rainforest
21.03.2019 | Forschungsverbund Berlin e.V.
The inner struggle of the evening primrose: Chloroplasts are caught up in an evolutionary arms race
14.03.2019 | Max-Planck-Institut für Molekulare Pflanzenphysiologie
DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.
The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...
Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.
The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...
Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.
Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...
Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.
"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...
11.03.2019 | Event News
01.03.2019 | Event News
28.02.2019 | Event News
25.03.2019 | Trade Fair News
25.03.2019 | Life Sciences
25.03.2019 | Information Technology