Healthy Soils

The best solution for climate, water quality, and your next meal

CREDIT: ISTOCK/BURWELLPHOTOGRAPHY

It’s an entertaining and yet shocking pastime to read vintage advertisements. Today, we shake our heads in amazement at bygone celebrities who extol the relaxing and “digestive benefits” promised by smoking a particular brand of cigarette, at manufacturers who quaintly promote a children’s “lead party” with their paint icons, and at a charming toddler whose bathing suit is pulled by an equally charming puppy revealing her tan, the benchmark of healthful sun worshipping for decades.

It’s through this retrospective lens that we also view what we now know to be environmentally harmful home and lifestyle improvements: phosphates in soaps to clean better; CFCs (chlorine, fluorine, and carbon) to conveniently aerosolize everything from hairspray to asthma medicine; and new antibiotics that became a staple of livestock feed. And when enterprising investigators discovered that ammonia could be modified under heat and pressure, farmers leaped to deploy the new chemical fertilizer with the promise of less work, increased yields, and higher profit margins.

Unfortunately, such innovations were enthusiastically adopted with little thought to their potential harm to people or the environment. And if a little nitrate fertilizer is good for production, well, more might be a whole lot better. In fact, from 1960 to 1990, synthetic nitrogen use increased sevenfold, yet as early as the 1970s scientists were conducting hydrologic tests to study the “present controversy over the role that N-fertilizer use may have in reducing our water quality.”

While the Clean Water Act of 1972 mandated wholesale cleanup by industry, agriculture was—and even now remains—largely exempt from nutrient regulatory policy. Given the statistics, it’s still easy today to point to farmers as a primary source of watershed contamination. Yet, ironically, the more the soil was treated, the less robust it became, until fertilizer became not just an amendment but a necessity.

After decades of research on the relationships among nitrogen fertilizer, soil, water, and air, there is more truth now than ever before in the caution, “We all live downstream.”

The Land Mirrors the Farmer
Rattan Lal, professor of soil science and director of the Carbon Management and Sequestration Center at The Ohio State University, says he much prefers to look ahead for realistic solutions rather than castigate sources of the problems. His mission of promoting awareness that “soil is everything, and we must protect and take care of it” takes him to all corners of the globe conferring with scientists, presidents, and international decision influencers. But the real change, he says, starts from the “ground up.”

“We’ve been blaming agriculture for everything, but we forget that it’s feeding us three times a day,” affirms Lal.

He adds that farmers do want to take care of the land, but land is degraded when they are desperate. “When farmers are miserable in times of trouble, they pass on this misery to the land, so we must make sure farmers are happy.”

Lal, who has spent his career in the intensive investigation of soil health, says soil content—”healthy soil”—and erosion, aquifer contamination, and water quality are inextricably linked. He explains that erosion is determined by three factors.

“First are the land characteristics—that is, the soil type, the gradient, the length of slope, and the vegetative cover. Second is climate—rainfall, wind, intensity, and frequency of both these and other forces of nature. Third, and most critical, is human management and how people address the challenges of the first two.

“Farmers cannot do anything about climate, but they can do several things about the composition of land, by modifying, terracing, and changing cover crops. Managing the soil and improving and protecting soil carbon content is a key effort that has direct impact on erosion.”

Lal explains that the susceptibility to erosion is directly linked to soil structure; making it less susceptible and more resilient must involve increasing soil strength.

“As the concentration of carbon increases—that is, the amount of organic matter in soil—the texture, strength, and structural attributes improve. This makes it less susceptible to erosion. You can say it is directly proportional: that as carbon increases, erodibility decreases.”

When the soil’s structure is strong, it can hold water in the top root zone and increase both the plants’ and soil’s capacity of “acting as a sponge to hold water against gravity.” Equally important, Lal says, is keeping the ground covered at all times. “If you keep a buffer against raindrops and create intercept fields with grasses that break up long sloping terrain, you reduce water velocity coming off the land.”

But he says asking farmers to be good stewards of the land out of altruistic fervor, while an idealistic concept, is not always practical or realistic. “We need to have a payment system for what I call ‘ecosystem intervention.’ We’re asking farmers to plant cover crops, to employ the latest creative methods to introduce high content of organic matter to the soil, but we should compensate them for this service. Not as a subsidy, but a compensation of so many dollars per acre to buy technology and seed and pay for labor and time to deploy these strategies.”

Lal says that policymakers are finally catching on that in order to feed the fast growing planet with nutritious, sustainable food crops, something must be done besides debate the probabilities. Food security is an underappreciated but very real concern for global stability in the face of climate change and new weather patterns, he says.

But Lal’s efforts are focused more broadly beyond guaranteeing a fully stocked grocery shelf. The global impact of sustainable, high-carbon soil has far-reaching effects that Lal outlines as a complex landscape of disparate but interdependent features. “High-carbon soil can help mitigate erosion and also climate change, improve water quality, improve agricultural productivity, and even reduce potential civil unrest.

“In Africa, where chemical fertilizer is rarely used, the per-hectare production output is at the same level today as it was 50 years ago. Erosion is terrible, and water availability and quality can achieve perilous states. The consequence is lakes dry up, livestock and people go wanting for food, and people who are hungry and are lacking technologies for sustainable agriculture will almost certainly turn to any means of staying alive at any expense to the environment.

“When governments use force to control the farm practices of poor people eking out a living with hand tools, or mandate environmental practices they can least afford, conflict is almost guaranteed. Lives can and have been lost in this effort,” he says. “This is why I say that the health of soil, and that of plants, animals, people, and the ecosystem, are one and indivisibly connected.”

He adds, “Soil is like a bank account. You cannot take out more than what you put into it. If you keep on taking out by harvesting and do not replace the nutrients, the soil heads on a downward spiral of depletion.”

He notes, “While we have instituted laws for public policy on air quality and water quality, the tragedy is there is still no law on soil health, and yet they are all inextricably linked.

“We need to help farmers, and if you think about it, with 150 million hectares in production in this country alone, say we pay them even 16 dollars an acre to plant cover crops and keep the land covered—what is that? The cost of less than fifty new fighter jets?”

Credit: ISTOCK/GOMEZDAVID

CREDIT: ISTOCK/GOMEZDAVID

MoFoLoPo: Not a New Rap Song
Eric Davidson heads up the University of Maryland Center for Environmental Sciences’ (UMCES) More Food, Low Pollution effort, or MoFoLoPo. He echoes Lal that reinvesting in the natural capital of soils must be a combination of tactics. He agrees there is no one-size-fits-all solution. But simply presenting farmers a menu of best management practices will not bring overnight changes.

“There have been many experiments, including an ­insurance plan that guaranteed a price to farmers if they used less fertilizer, but it didn’t work,” he notes. “It turns

out that putting on a little extra fertilizer is a pretty cheap insurance policy that is often a good investment. When the stars align to produce good weather and good commodity prices, a little extra fertilizer can result in a bumper crop.

Credit: ISTOCK/AMENIC181

CREDIT: ISTOCK/AMENIC181

In years that the weather doesn’t cooperate as well, such as a drought, late frost, or other factors, they haven’t spent much on that extra fertilizer, so it isn’t a high risk for them. The bigger risk is letting the good years get away without reaping optimal rewards.”

Encouraging farmers to adopt new tools, though, can play a crucial role in nutrient management, such as using the technology we already have to monitor crop nutrients.

“Measuring the nitrogen content of leaves and soils at key points during the growing season can determine if there is enough nitrogen or if more needs to be added to boost yield,” says Davidson. Timing is key for improving yield and avoiding wastage and pollution.

Another innovation is new tools developed for tractors, such as high-clearance wheels that allow farmers to drive through fields without damaging young plants and to apply modest doses of fertilizer at the times that the rapidly growing young plants need it most. Another technology is onboard sensors that measure light reflected off crops; an onboard computer uses that information to calculate nitrogen needs and then adjusts the amount of fertilizer released out the back of the tractor as it moves down the crop row.

Davidson says many farmers now hire agricultural consultants whose companies provide a bundled product, including planting and fertilizing according to technologies that they have developed. “These specialists can create a GPS of your farm and will help you monitor and measure your nutrients as they vary across your fields, tailoring needs to specific areas.”

As one whose career at UMCES is focused on research and practices for environmental stewardship, Davidson is trying to balance the need to address the food demands of a growing global population with minimizing nutrient losses to the environment. He welcomes technological solutions, but emphasizes, “There are also economic and sociological factors at play here. We have to be mindful of the social and economic signals that affect farmers’ decisions and where they go for their most trusted information about nutrient management. Partnering with private sector consultants who are certified nutrient managers may be an effective way to get up-to-date information to the farmers who hire them.”

Davidson says this challenge requires addressing multiple issues, and lessons learned from averting erosion provide a good precedent. “There has been a lot of progress made in the science of erosion control, largely coming from what we learned from the devastation of the Dust Bowl, when policies were created to reduce erosion to the benefit both of farmers and of society.”

He says the outcome of the Dust Bowl “galvanized a whole community to focus on erosion. So today, erosion management, while still a problem in some places, is in much better shape than is nutrient management, and we need to apply those lessons today to nutrient management, again seeking to benefit both farmers and society.”

And one motivating source to help advance that progress is coming literally from the top end of the food chain—the people who buy the commodities.

Mid-crop harrow

Mid-crop harrow

Reach the People Who Reach the Farmers
Allison Thomson, science and research director at the Washington DC-based nonprofit Field to Market, The Alliance for Sustainable Agriculture, explains how managing the environment from a producer’s perspective is good for farmers, for business, and for the environment.

“Field to Market is celebrating its tenth year and has grown to include 117 member organizations,” she says. “These members represent farmers, agribusinessines, retailers, farmers, civil society, food and retail companies, environmental NGOs, and academia. All are stakeholders in the food supply chain and work together toward a more sustainable agricultural system.”

No-till practices help infi ltrate water and reduce nutrient loss.

No-till practices help infi ltrate water
and reduce nutrient loss.

Members collectively contribute to governing and growing the Supply Chain Sustainability program, which measures the environmental outcomes from individual producers through the web-based Fieldprint Calculator, Thomson explains.

“Members also work with producers in supply chain projects that connect food and retail companies with farmers through multi-stakeholder parternships. Together they work toward continuous improvements of agricultural sustainability as defined by our set of eight metrics.”

The Fieldprint Calculator tool allows members to calculate seven metrics on sustainability: land use, energy use, greenhouse gas emissions, soil conservation, soil carbon, irrigation water use, and water quality. An eighth metric, biodiversity, is in the pilot phase.

Reaching the people who advise the farmers—the certified crop advisors, agriculture retailers, university extension programs, and others—is also important to sustainability, says Thomson. “These are the advisors who are already consulting with the farmers, so we can engage them in supply chain projects to enhance the sustainability guidance they offer. For example, advisors on a project can explain a farmer’s scores: ‘Here is how much greenhouse gas footprint you produce; here’s your water-quality output from your farm.’ The grower then has an indication of how well nutrients are or are not being absorbed, which impacts their bottom-line, and can encourage farmers to try new practices.”

Cover crops

Cover crops

The online tool allows individual users to calculate their scores and they can elect to join a supply chain project. Supply chain projects are initiated in a number of ways, including by food companies that map their supply region for a specific commodity and then work to engage farmers they are sourcing from, which Thomson says can be very enlightening for all partners involved.

“For example, Unilever discovered that all the soybean oil used to make Hellman’s mayonnaise comes from one Archer Daniels Midland [ADM] facility in Iowa. So they developed a partnership with ADM, Iowa soybean farmers, and other NGO and local partners to develop a supply chain project. They have worked together and engaged 700 farmers in the supply region. Farmers have entered data into the calculator and have had meetings to talk to about metrics scores and discuss opportunities for improvement. Project partners are also working to encourage and support farmers to adopt cover crops through a cost-sharing program.”

Nonetheless, despite the best intentions, Thomson says the fate of nutrients is dependent on many different conditions that are outside the control of an individual farmer, such as weather events.

“But food companies are motivated to help farmers meet the challenges of more sustainable production to ensure adequate food production and a healthy environment over the long term,” she says. “Everyone is motivated to work to improve our food supply.”

She adds that there are variances in geographic regions: differences in soil type, differences in climate, and changing weather patterns that all make for challenges in data gathering and analysis.

“It’s crucial to understand how different practices in different regions affect the fate of nutrients and sediment, which together impact water quality. But our knowledge gap is not necessarily about building a better model, but understanding what we do know better, and the environmental consequences of those factors.”

Star Ratings for Farmers
For decades, environmentally conscious consumers have been able to select appliances and fixtures whose efficiencies meet the WaterSense or Energy Star standards. Now something similar is available for farmers: NutrientStar.

Karen Chapman, manager of agriculture sustainability and the administrator of the Environmental Defense Fund (EDF) NutrientStar program, explains, “These days consumers have a lot more interest in food—where does it come from, is it grown sustainability—and people want to know if they are making choices in food that is grown under environmentally-responsible conditions.”

The NutrientStar program is a division of the EDF, a not-for-profit organization that takes a multidisciplinary approach to solving environmental problems. This includes partnerships with policymakers, corporations, and consumers. The EDF is also a member of Field to Market.

“The EDF has partnered with manufactures in our food supply chain like Walmart and General Mills. These companies were looking to find a means that defined sustainable sourcing, and they asked us how we would go about ‘recommending’ one grain producer who used best management practices over another,” says Chapman.

She says the EDF devised the labeling of NutrientStar to denote producers whose grains and products like fruits or vegetables were grown using cover crops and techniques to advance soil health and manage nutrients.

“We had to define what exactly is a sustainable source, and NutrientStar is a toolbox that farmers really like. Every top producer we’ve talked to is unbelievably enthused. Farmers have so many choices, and we’re trying to close the gap between information and implementation with the best decision support and modeling tools.”

One example she cites is changing practices for nutrient management in different parts of the country, encouraging Midwest corn producers to move nutrient application from the fall to the spring.

“Our models are tested by a science review panel and respected industry representatives, and these show that farmers will save money and reduce runoff significantly. It’s known that fall fertilizer application is lost both to the air and to water, through runoff in snowmelt and fall and spring pre-planting rains.”

She says that for the supply chains to make recommendations, “you need to be able to measure the impact and success of changes to the environment. Unless you have some data and provide transparency in practices, there is no proof.

“However, unlike EnergyStar for a dishwasher, which is conferred by the EPA, we’re not an official certification. Once we have data for a product and how it performs in nutrient efficiency benefits, we will post on our website. But efficacy field trials take time, and we have a cadre of farmers and consultants we are working with to validate data and then make that data public.”

But as Davidson cautioned, Chapman agrees that although farmers receive a lot of information, they must question whether it’s in their best interests. “The majority of them go to their retailers, who make a commission on products, so their agronomic advice can be biased,” she notes. “Ultimately, we find that farmers do want to be good stewards and there is a range of adopters of new technology regarding nutrients. The trajectory of the early adopters who take it on and use new products and get good results will incentivize others; they’ll share what tools help and what is just ‘fairy dust.'”

Easier to Go to the Moon Than to Raise Corn
Understanding the complex relationships between soil, sediment, and nutrients, and solving ongoing water-quality issues, has been the mission for Jerry Hatfield at the USDA’s Agricultural Research Service National Laboratory for Agriculture and the Environment in Ames, IA.

“We have a national responsibility here to look at everything—from water quality, to air quality, to volatilization of pesticides, to what’s coming down in rainwater—not just here in Iowa and the Midwest, but across the US,” he says. “Right now we have efforts to determine where you put conservation practices that can be most effectively utilized in respective watersheds.”

For example, he describes a hydrologically based picture of a watershed to include “topography, slope, all the different features that allow you to do water routing and then determine where is water flowing off a field, off other fields. By looking across the system, you can see what edge-of-field practices would work, where would bioreactors best fit, bank stabilizations, and more.”

Hatfield says he’s been trying to get producers to understand that if they improve their soil and water availability, they can start stabilizing their yield, as well as stabilizing biological activity.

“When we promote biological activity, we produce nutrient cycling,” he says. “We see a lot of turnover of nutrients. If you go to long-term, no-till practices, you end up with less leaching runoff. Then the system is tuned to what the plants need.

“If we want to solve soil problems and water quality problems, we have to understand nutrient dynamics and water together. In fact, water, even more than nutrients, is the limitation to yield, so we have to get producers to understand this and adopt practices that look at water as the dominant feature in crops.”

Hatfield echoes other experts that farmers get a lot of information, but the quandary is deciding which is the best source for their particular operations. What works in one part of the country, or even one part of the state, may not work for their farms.

“I tell people farming isn’t rocket science. All you need there is to know payload, force of gravity, and how much thrust. By comparison, farming is much more complex. You need several equations to optimize a production system that doesn’t have an engineering solution, since there are no constants in farming,” says Hatfield.

He notes that there is plenty of research on nitrogen relative to yield, but that those studies don’t necessarily focus on the attendant environmental quality. And then there is nitrogen research that “never talks about weather during the growing season, which is a major limitation,” he says.

“We have to get past these individual line items and look at the interactions. There is not consistent response; it’s all about how factors interact in non-constant systems.”

Hatfield adds that farmers “are surprised the USDA has this information for them. Unfortunately, since every state has cut its extension agent program, there are fewer agents these days, so we have to make ourselves available to them.”

He emphasizes that soil management to improve water storage will have the biggest impact on erosion and stormwater runoff. “If we can take a 6-inch rain and make it look like a 4-inch rain before runoff, we’re changing the whole flashiness of the system. Protection with these residue layers from cover crops and no-till practices will absorb raindrop energy, and holding water is key.”

But more than half of the 400-million acres of US farmland is rented out to tenants. Do farmers who don’t own the land really worry about improving the soil?

No One Washes a Rental Car
Some say that if you rent rather than own, your interest in maintenance is less than if you have a stake in the investment. However, Jim Lewis, a Maryland farmer and Dorchester County extension agent, says the rental car comparison just doesn’t apply.

“People who are renting farmland may be taking on a neighbor’s land where the husband has died and the widow is keeping the property. This is more common than you might think. She can rent this land to nearby farmers who keep it in production, and they in turn are hoping to keep it operating for a long time. It only makes sense that they would do the best they can to keep production at high levels, and while they may not hold the land title, they are just as interested in water quality and contamination of the watershed they use. So yes, they are interested in treating the land well,” says Lewis.

He describes his local area of Maryland that borders the eastern shores of the Chesapeake Bay as highly aware of nutrients because of environmental regulations surrounding the bay. “We’re a good 30 years ahead of the rest of the country. Use of no-till practices, application of fertilizer in spring not fall, and cover crops have made good strides in reducing contamination and improving production with better soil quality,” he says.

And conservation practices have made measurable impact. Lewis says farmers in his area are down to eight-tenths of a pound of fertilizer for a bushel of corn. “Compare this to places I’ve visited in Iowa and Illinois where they are applying fertilizer in the fall, losing a lot, and not using cover crops. They give no credit to past nitrogen, and they may be using over two pounds of fertilizer per bushel. We put it on when plants need it and use it.”

He also notes that the program paying farmers in his region $35 to $50 an acre to plant cover crops is lower than in some other places. “It goes back to finances. If there is no state or federal cover crop program, you have to absorb the costs of those seeds, the diesel to plant them, and other costs.”

Another factor in the equation is the price of fertilizer. When nitrogen prices were higher, Lewis says, farmers could use a legume cover crop and it justified the price of the seeds. “If nitrogen goes high enough, we can justify a green manure crop. Clover, vetch or peas, rye grasses, or triticale can grow me 70 pounds of nitrogen.”

He adds that farmers in the region haven’t tilled the fields “since I was a kid, but we did it to change our economies. We had to cut dollars, and it was cheaper to not do tillage. There’s less equipment, less fuel requirement, and it’s good for the soil. It’s just a more profitable way to farm, and in some cases on some soil types we’re seeing increased yields.”

He also uses water control structures to back up water during portions of the year, which reduces losses to the environment; creates stream buffers; and uses in-season nitrate tests to “put truth in the samples and fine tune fertilizer recommendations and use. This way, when we test along the way and time fertilizer with crop needs rather than overloading in the winter or spring, we’re saving on nutrients, and we’re preventing loss of nutrients.”

But he concedes that what works on the Eastern shore may not work in the Midwest. The soils around the Chesapeake Bay are very sandy and the water table is shallow, so water simply soaks in quickly. In other regions with clay soils, runoff and erosion is a bigger problem. Lewis says other contributors to nutrient runoff, such as the effect of urban growth, must also be part of the conversation.

“No one talks about failing septic systems, but on this side of the bay there are many developments springing up around the desirable waterfront, and if septics are not done properly, or if they are old and fail and are close to water, there’s a potential problem. It’s easy to point the finger at agriculture, but farming is just one of the pieces of this problem, not the entirety.”

The Final Word
As Lal and other experts agree, preserving and improving the carbon content of soil is essential, regardless of political agendas or geographical boundaries. “Increasing the soil carbon is now a goal for leading organizations in Europe, Asia, Africa, and here in the US as well,” says Lal. “Only with sufficient carbon concentration can we effectively both mitigate climate change and improve food security. With the UN predicting nine billion people to feed by 2050, this is absolutely what we should be doing right now, not later. It’s a goal everyone can get behind to support if they understand the short- and long-term necessity.”

Elsevier, a publisher with a menu of 1,800 highly respected professional journal titles, announced that in 2013, Rattan Lal’s original research paper “Food Security in a Changing Climate” (Ecohydrology & Hydrobiology 13:8-21) was the all-time number-one article requested as an electronic download from the publisher. In the paper, Lal presents the challenge to food security from population increase, land competition, soil degradation by erosion, decreased water, and animal-based diets as the crucial factors global policymakers must address to protect and preserve sustainable agriculture. He proposes ecosystem
services implemented by farmers as a useful strategy to help ensure food security.

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