Farmers in the Corn Belt are taking the issue of nutrient loss seriously, but they are seeing mixed results from efforts to keep fertilizer on their fields.
Surveys have shown an increasing percentage of farmers are aware of the problem and are engaging in practices designed to reduce loss of agricultural chemicals, especially fertilizer.
The latest report from Illinois’ Nutrient Loss Reduction Strategy indicated that nitrogen levels increased by 7% in the state’s river system. But there was also some good news.
“What gets lost in the details is that the Illinois River — which is by far the biggest load of water that leaves the state — actually went down in nitrogen levels,” said Jean Payne, president of the Illinois Fertilizer and Chemical Association.
Though total fertilizer use has risen, farmers in the state have reduced nitrogen rates in corn, studies show. The state launched the NLRS in 2015 with the goal of improving water quality in Illinois and the Gulf of Mexico by reducing phosphorus and nitrogen losses by 45%.
Farmers have taken a number of steps to address the problem while improving the bottom line. Among other things, they have lowered rates of nitrogen while increasing corn yields. The old recommendation was 1 pound of nitrogen per bushel, but they have been successful with an average of only 0.7 or 0.8 pounds.
“We’ve made a lot of progress,” Payne said. “We’ve done a really good job of convincing growers they don’t need that extra 20 or 30 pounds. You take a lot of that extra nitrogen out of the equation, that’s significant.
“Go back to 2012 or 2013 and everybody thought we were overusing nitrogen. ... We were able to do research and found out it’s about management practices. Applied fertilizer is just a very small part of the equation because we lose nutrients out of soybean fields that never get any fertilizer put on. They might be using the same amount, but yield trends in Illinois have increased. We’re not using more nitrogen — if anything, we’re using same amount or less in many fields.”
Iowa State University Extension surveys show more than 70% of farmers are knowledgeable or somewhat knowledgeable about the Iowa Nutrient Reduction Strategy. And while mitigation efforts have increased, there is room for improvement.
As in Illinois, corn producers in Iowa are getting more bang for their buck when it comes to getting yield increases with less per-bushel nitrogen application.
“We have some survey data that tells us nitrogen rates have increased,” said Jamie Benning, water quality program manager for Iowa State Extension. “We are producing more corn per acre, but we’re not exporting more nitrogen in the grain.”
Laurie Nowatzke agrees.
“Certainly production per acre is coinciding with the nitrogen rate increase,” said Nowatzke, measurement coordinator for Iowa’s nutrient reduction strategy initiative. “But that doesn’t mean there are benefits in water quality. There are still negative implications.”
The planting of cover crops is increasing in Iowa, but accounts for only about 1 million of the nearly 23 million acres of cropland.
Nowatzke pointed out that some farm management practices provide benefits in addition to soil health.
“Some of the more traditional soil erosion prevention practices — such as terraces and conservation tillage — are increasing,” she said. “Back in the ‘80s there were effectively no acres of no-till in Iowa, and now we’re up to a third of crop acres are in no-till. This push for soil conservation has had a lot of success. It has resulted in a pretty significant decrease in phosphorus loss.”
Farm groups support voluntary mitigation efforts by farmers to address the problem of nutrient loss. Nitrates and phosphorus that escape farm fields and industrial sites are carried by the Mississippi River to the Gulf of Mexico. That creates hypoxia, a reduction of oxygen levels in the sea, which kills marine life and affects the seafood industry, among other things.
As part of a USDA study, Illinois State University professor Maria Boerngen and graduate student George Hoselton surveyed members of the Illinois Corn Growers Association to get an idea of their awareness of the problem.
Two-thirds of the 762 respondents reported that they are familiar with the NLRS and most expressed support of addressing the issue on their farms.
“The vast majority was concerned about nutrient loss and changing farming practices because of those concerns,” Boerngen said. “These corn growers are very aware of those issues and are doing things about them.”
Problems in practice
While a large majority of farmers surveyed understood the problem and indicated they believed mitigation efforts are warranted, not all believe the issue is cut and dried. Some expressed concern about problems associated with those efforts, such as difficulty in killing cover crops in the spring.
“In some cases they didn’t think the benefits would be worth the work,” Boerngen said. “If you have a delay in terminating a cover crop, that delays getting in the field to get a crop planted. That creates a ripple effect.”
Illinois Farm Bureau began a serious effort to address the topic in 2015, with a 10-year goal of reducing nutrient loss. The members have wholeheartedly embraced mitigation efforts. A call for volunteers to conduct side-by-side trials in their fields drew enthusiastic response.
“We put the request out the first week of planting season,” said Lauren Lurkins, IFB’s director of natural and environmental resources. “We were looking for eight to 10 farmers. We’ve had over 50 farmers call and say they want to help.”
Many field management practices have a dual purpose, including cover crops.
“A lot of times people are trying it out for the soil health benefit,” Lurkins said. “People are still making those investments on the farm, such as cover crops, grass waterways and buffer strips.”
Lurkins said farmers are committed to solving the problem, and understand that it’s a long-term commitment.
“We look at that issue of nutrient loss reduction as a long game,” she said.