Crop production linked to regional changes in climate


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Corn and soy plants can cool the climate on a regional level, but intensified conventional agriculture can harm water and soil quality. (Lana/flickr)

Jenna Ladd | February 14, 2018

A new study by researchers at Massachusetts Institute of Technology and Dartmouth College detail the way intensive agriculture has influenced precipitation and temperature patterns in the midwest.

During the second half of the 20th century, corn production in the midwest increased by 400 percent and soybean yields doubled due to more intensive agricultural practices. The study, which was published in Geophysical Research Letters, found that the midwest also saw significantly more precipitation and lower temperatures during the summer months over the same period of time. They concluded that the changes were not merely correlated, but that the land use change actually caused the regional climate changes.

The authors explain that each time plants take in carbon dioxide, they release moisture into the atmosphere through pore-like structures called stoma. With more plentiful and robust plants due to intensive agriculture, the amount of moisture corn and soy crops collectively release into the atmosphere has increased in the midwest since the 1950’s. This extra moisture, the study found, has caused summer air to cool and more precipitation to fall. In the last fifty years, average summertime rainfall in the midwest has increased by 15 percent and average summer temperatures have dropped by 0.5 degrees Celsius.

Roger Pielke Sr., a senior researcher at the University of Colorado at Boulder commented on the study, he said, “This is a really important, excellent study. The leadership of the climate science community has not yet accepted that human land management is at least as important on regional and local climate as the addition of carbon dioxide and other greenhouse gases into the atmosphere by human activities.”

Since completing the study, the researchers have developed a formula that accounts for the causative relationship between plants and regional climate changes that can be entered into U.S. regional climate models. It correctly predicted those changes that have been observed in the midwest over the last 50 years.

The study opens the door for further research into land use changes and how they can affect local climate.

As global temperatures rise, future of agriculture uncertain


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Soybean yields could decrease by as much as 40 percent due to rising temperatures. (United Soybean Board/flickr)

 Jenna Ladd | January 20, 2017

Without further action to curb greenhouse gas emissions, global temperatures are expected to rise as much as 6.1 degrees Fahrenheit above pre-industrial averages, which may meaningfully impact agricultural outputs.

According to a recent study by the the Potsdam Institute for Climate Impact Research and the University of Chicago, rising temperatures could significantly reduce U.S. grain harvests. Using a set of computer simulations, the researchers found that yield reduction could reach 40 percent for soybeans and almost 50 percent for corn by the end of the century if carbon emissions are not cut drastically. Wheat would fare slightly better, with its yields decreasing by an estimated 20 percent.

The researchers said, “The effects go far beyond the U.S., one of the largest crop exporters. World market crop prices might increase, which is an issue for food security in poor countries.”

A report by the European Union’s Joint Research Centre came to a different conclusion. They found that wheat may actually benefit from higher concentrations of carbon-dioxide in the atmosphere, while corn yields would decrease.

Although the global temperature has reached record highs for three consecutive years, U.S. corn and soybean yields were seemingly unaffected. Thanks in part to genetically modified seed, which can have adverse environmental impacts, corn and soybean output was higher than ever in 2016.

However, the extreme drought of 2012 serves as a reminder that agricultural productivity is vulnerable to a changing climate. That year, U.S. corn harvests decreased considerably and caused global corn prices to skyrocket.

Soybeans may play bigger role in nitrate levels than previously thought


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IIHR’s water-quality monitoring network has generated interesting data that contradicts some widely-held beliefs regarding corn and soybeans and their impact on nitrate in Iowa’s streams. (IIHR)
Jake Slobe | September 28, 2016

New research shows that soybeans may play a key role in the transport of nitrate from farmed fields to the stream network.

As Iowa farmers have planted more acres of corn to meet the increasing demand, many models predicted that nitrate concentrations in Iowa streams would increase as a consequence. However, a new study conducted by the UI’s IIHR-Hydroscience & Engineering group and the Iowa Soybean Association, published in the Journal of Soil and Water Conservation, challenges many of these predictions.

As the amount of corn planted increased and the amount of soybeans decreased, fertilizer application increased by 24 percent in the watershed. Surprisingly, the nitrate levels in the river saw no increase and in some cases saw slight decreases.

The study evaluated 7,000 water samples in the Raccoon River Watershed from 1999- 2014 and had access to fertilization data for 700 fields in the watershed. The result from the study has led researchers to believe that nitrate levels are less dependent on corn production than previously thought.

IIHR —Hydroscience & Engineering researcher Chris Jones says that clues to the reduction in nitrate levels can be found in the differences between corn and soybean  growth, soil chemistry, and the decay of other crop residues. Conversely, the dead and decomposing soybean plants can increase the amount of nitrate in the soil vulnerable to loss.

“We know we can’t just focus on fertilization of corn. We need a systems approach to improve water quality. It also demonstrates the power of monitoring water quality. Without this data, we could easily have missed this important and counter-intuitive conclusion.” 

As a result, Jones says he believes that declining amount of soybeans planted may have reduced the cropped areas most susceptible to nitrate loss, more than compensating for the increased fertilizer inputs on corn production.

 

Iowa State researcher looks at corn’s adaptive powers


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The corn plant can grow in high elevations near mountain ranges or at sea level, researchers at the Iowa State University are taking a closer look at what makes this crop so versatile. (jev55/flickr)
Jenna Ladd | September 20, 2016

An Iowa State University researcher is taking a closer look at how corn has adapted over many centuries to prosper in several different environments and elevations throughout the Americas.

Matthew Hufford, an assistant professor of ecology and evolution and organismal biology at the University, is co-principal investigator of a collaborative study with scientists from University of California at Davis, University of Missouri, and the National Laboratory of Genomics for Biodiversity in Irapuato, Mexico. The research project recently received a five year, $4 million grant from the National Science Foundation. About $800,000 of those funds will be used to support Hufford’s laboratory at Iowa State University.

Hufford said that gaining a better understanding about how corn adapted to grow beyond its origin in Mexico could help plant breeders to produce crops that perform better. He said, “With this project, we hope to identify good candidates for genes that played key roles in helping maize adapt,” he added, “You could use that new knowledge to design corn to deal with the environmental challenges of today, like climate change and other stresses.”

Corn started growing in the hot lowlands of southwestern Mexico about 10,000 years ago. Hufford explained that in a relatively short amount of time the plant has changed to grow in much higher elevations with different climates across the Americas. After he compared highland corn to lowland corn, Hufford found that highland corn is darker in color and equipped with macrohairs that insulate plant when temperatures drop. Striking differences such as these help explain how the plant is able to grow anywhere from near sea level up to 13,000 feet in elevation.

Moving forward, the researchers plan to cross highland corn with lowland corn in order to study the genetics of parent and offspring varieties.

Southeastern Iowa experiencing “abnormally dry” conditions


(Chris Fenimore, NOAA/NESDIS/NCEI)
(Chris Fenimore / NOAA/NESDIS/NCEI)
Nick Fetty | June 21, 2016

About 14 percent of Iowa experienced abnormal dryness during the early part of June and since then that percentage has nearly doubled.

Data from the Drought Mitigation Center show that Iowa’s southeast corner is the driest region in the state. This region includes much of the area south of Interstate 80 and east of Interstate 35.

Drought intensity is measured on a five-point scale from “abnormally dry” to “moderate drought” to “severe drought” to “extreme drought” and finally “exceptional drought.” The Hawkeye State has not experienced severe or extreme drought since 2012.

Dr. Deborah Bathke, a climatologist with the Lincoln, Nebraska-based Drought Mitigation Center, warmed that if the current weather conditions continue it may lead to a “flash drought.”

“If we continue to see these high temperatures and lack of precipitation, I can see us quickly evolving into what we like to call a ‘flash drought,’ which is when we have this rapid onset of high temperatures combined with a lack of precipitation that really starts to desiccate our soils and stunt our crop growth,” Dr. Bathke told Radio Iowa.

Soil conditions have also varied across Iowa with most of the northern third of the state experiencing “adequate to surplus” levels of moisture in topsoil compared to southeast Iowa where over 60 percent of topsoil moisture levels were rated “short to very short,” according to the most recent Iowa Crop Progress & Condition report by the U.S. Department of Agriculture.

Despite the hot and dry conditions in southeast Iowa, the USDA report found that statewide just 4 percent of Iowa’s corn land is classified as “poor” or “very poor” while 3 percent of soybean land falls into those same categories.

Branstad questions EPA’s new Renewable Fuel Standard


Iowa governor Terry Branstad at a 2011 event in Des Moines. (Flickr)
Iowa governor Terry Branstad at a 2011 event in Des Moines. (Gage Skidmore/Flickr)

Nick Fetty | June 26, 2015

During a public hearing of EPA’s new Renewable Fuel Standard in Kansas City on Thursday, Iowa governor Terry Branstad questioned the new policy and the economic impact it will have on the Hawkeye State.

Nearly 300 people made statements during the public event which will be the only one EPA plans to host before a final decision is made in November. Brandstad and other supporters of the current fuel standard feel that it is necessary “to force oil companies to improve infrastructure at gas pumps to deliver ethanol fuel blends above the current 10 percent mix.”

“The EPA has a choice: protect the deep pockets of Big Oil and their monopolistic practices or nurture consumer choice, renewable energy growth and a healthy rural economy,” Branstad said.

The proposed plan, which was set by congress, calls for a reduction of 4 billion gallons this year and an additional 5 billion gallons in 2016. Branstad cited the financial impacts the proposal would have on Iowa’s economy pointing out that corn has gone from $6 per bushel in August 2013 to $3.45 per bushel currently. He said this has caused uncertainty in the market and has led to fewer investments in biofuel technologies.

Proponents of the new standard say that it would increase overall biofuel production and use over time. Officials from the oil industry also argue that retailers are not equipped to sell gasoline with ethanol levels greater than 10 percent and that customer demand has not warranted an investment in new infrastructure.

Other have questioned the feasibility of biofuels altogether, citing that production requires large amounts of water and other resources.

Iowa leads the nation biofuel production with 42 ethanol plants and 13 biodiesel plants.

Wet conditions hamper fieldwork in May


Fall crops and standing water from rains in 2009 in Polk County (Carl Wycoff / Flickr)
Fall crops and standing water from rains in 2009 in Polk County (Carl Wycoff / Flickr)
KC McGinnis | June 2, 2015

Rain, cool temperatures and standing water halted Iowa farmers for parts of last month, slowing crop progress by limiting suitable days in the field.

The USDA’s National Agricultural Statistics Service reports that in the last week of May just 2.3 days were suitable for fieldwork across the state, with only 1.7 suitable days for southwest Iowa. Topsoil moisture was rated at above surplus for 50% of southwest and south central Iowa, and 22% across the state. That’s compared to last year, when only 7% of Iowa topsoil was at surplus moisture.

This excess moisture has made it difficult for farmers to get in their fields, leading to lags in soybean planting and alfalfa hay first cutting, which was only at about half the five-year average. Some operators reported standing water in their fields, and some fields will need to be replanted due to the excess water. The moisture also prevented spraying, and led to concerns over muddy feedlots.

While 92% of soybeans were planted by the end of May last year, this year’s numbers were at 50% or less for parts of the state, with southwest Iowa reaching only 37%.

Iowa faced a similar situation last year, with consistent heavy rains in June and July leading to less than three suitable field days for three consecutive weeks. “We just came through three of our most challenging years, as far as weather goes,” noted northeast Iowa farmer Travis Holthaus in a recent CGRER documentary. Heavy rains, flash flooding and challenging droughts continue to lead to increased unpredictability for Iowa farmers. These producers may need to prepare for decreased field days in the next week as well, with more storms predicted later this week.