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Soil after a corn harvest is susceptible to erosion and compaction. Cover crops are a sustainable option that provide both protection and nutrients.

Cover crops thrive in times of drought

by Jessica Murphy
Jan 22, 2013


Jessica Murphy/MEDILL

Planting cover crops as a sustainable alternative to conventional corn and soybean rotations increases soil health and benefits the environment.

A warming planet and a drought that prompted the Department of Agriculture to declare the Grain Belt a natural disaster area has accelerated environmental and ecological awareness among Illinois farmers. One sign of this is renewed interest in cover crops.

“Cover crops are undoubtedly the hottest topic in agriculture right now,” said Russel Higgins, a commercial agriculture educator at the University of Illinois Extension. “They’ve been around forever but people have just started talking about them in the last couple years.”

Cover crops are planted after the harvest of principal cash crops such as corn and soybeans in order to improve soil quality and fertility, reduce erosion, and suppress weeds and pests. The most common types of cover crops include legumes such as alfalfa, crimson clover, and hairy vetch, a nitrogen-fixing flowering plant. Others include brassicas such as radishes and turnips, and grasses such as annual ryegrass and wheat.

A study released in July by the Leopold Center for Sustainable Agriculture found that adding diverse cover crops to a corn-soybean rotation could provide higher yields, reduce the need for fertilizer, herbicide and fossil fuel inputs, and protect nearby waterways from pollution. The environmental benefits of cover crops improve over time, the study concluded.

The Illinois Department of Agriculture has been working on promoting cover crops since 1988, according to Mike Rahe, the department coordinator.

“We currently offer cost share assistance through the Partners for Conservation program,” Rahe said. “It helps farmers pay for cover crop seeds with up to $40 per acre for 40 acres or a maximum of $1,600.”

Assistance programs for cover crops exist at the federal level as well, but considering the potential risk involved in changing farming practices, the incentives may not be enough.

“One challenge is that biology-based activities like the amount of nutrients recycled or the amount of organic matter created are hard to measure,” Higgins said. “So what we are trying to do is hopefully put numbers there.”

Ron Moore owns a family farm with his wife and three sons in Roseville, Ill., where they grow corn and soybeans on 2,000 acres. Moore said he was planning to implement cover crops last year but because of circumstances related to dry weather, it did not work out.

“I’ve just started investigating cover crops and their benefits,” Moore said. “The ultimate goal is increased productivity, increased yields, increased water penetration and decreased costs of herbicide.”

Moore said that he is planning to try planting cover crops again this year.

But a large number of Illinois farmers remain reluctant to adopt them. “Farmers are afraid of not knowing enough,” said Mike Plumer, an independent agricultural consultant who has done extensive research on cover crops with the University of Illinois.

A lack of information won’t be a valid excuse for long. Research on cover crops and efforts to educate farmers in the form of seminars, surveys and promotional activities have become widespread.

Cost is another reason some have been slow on the uptake, according to Higgins. Cover crop seeds cost about $25-$40 an acre in seed, which can quickly add up considering the average farm in Illinois is 368 acres.

“What farmers need to do is see there will be a return,” Higgins said. “Increases in yields and improved soil quality? That makes it worth while.”

A typical plant-to-harvest period for corn in Illinois is mid-April to mid-November; for soybeans, it is early May to early November. Cover crops are planted in the off-season time when the land would otherwise lie fallow and are plowed down before spring planting.

“Cover crops promote deeper rooting throughout the winter time,” Plumer said. “When you increase organic matter, you increase the water holding capacity so a crop can penetrate its roots much deeper.”

Plumer said he measured Illinois corn roots this year at 22 inches deep compared with a healthy crop that should reach at least 60-70 inches.

“The soils I review around the Midwest have severe compaction and degraded organic matter,” Plumer said. “This makes them more subject to severe weather conditions.”

Soil compaction occurs when the air between soil grains is displaced, making it difficult for the ground to absorb water and susceptible to runoff and erosion. Organic matter holds water and nutrients in soil, reduces compaction, and increases water infiltration.

The problem, experts say, is Midwestern soil is slowly being drained of its nutrients after decades of non-varied, chemical-heavy, subsidy-driven farming practices that are beginning to feel the heat of climate change.

NASA released 2012 temperature statistics last week as part of its finding that the climate is undergoing a long-term warming trend. The statistics indicated that 2012 was the ninth warmest year since 1880 and that with the exception of 1998, all nine have occurred since 2000.

Based on this trend it is reasonable to assume Illinois could be seeing higher temperatures and less water in coming years. Cover crops, though not considered a cure-all, could help make soil better able to sustain crops during a drought.

“If you have bare soil and a blazing sun, you’ll lose evaporative moisture and if you have a crop on that, you won’t lose as much,” Higgins said.

The modern agricultural subsidy programs of today were introduced in the New Deal, enacted by President Franklin D. Roosevelt in response to the Great Depression. These programs have evolved into a system that rewards the production of massive quantities of a select few crops, particularly corn and soybeans – Illinois’ top two agricultural commodities.

From 1995-2011 Illinois received nearly $12.5 billion in subsidies for corn alone, according to the Environmental Working Group’s 2012 farm subsidy database. Soybean subsidies in Illinois for the same period totaled $3.8 billion, wheat subsidies came in at $704 million and the total amount that Illinois received in agricultural subsidies was $19.7 billion.

Every five years or so the government passes a bundle of legislation commonly called the “farm bill.” While it has thus far done little to reduce farmers’ dependence on the subsidized, big-ticket crops, Congress is currently discussing a 2013 farm bill, which many hope will reflect and meet the challenges posed by climate change.

Advocates of sustainable agriculture are urging policymakers to see healthy soil and land, not the quantity of crop reaped from it, as the best investment and what farmers should be rewarded for.

Planting cover crops could be a good place for farmers to start.

“It’s something we need to be looking at and thinking about,” Moore said. “Farmers need to experiment with it for a year or two to see if it’s advantageous.”