A study recently published in the journal Global Change Biology sought to better understand which agricultural conditions are optimal for worms. Dr. Olaf Schmidt and Dr. Maria Briones analyzed 215 studies from over 40 countries that explored the relationship between tilling practices and worm population health.
The meta-analysis showed that disturbing the soil less (i.e. no-till farming, conservation agriculture) resulted in significantly more abundant earthworm populations. For example, no-till farmland saw a 137 percent increase in worm populations and a nearly 200 percent increase in soil biomass. Those areas of land in reduced-till for more than ten years saw the most earthworms return to the soil. In contrast, those field that were heavily plowed lost half of their original worm population.
Researchers observed the affect of tilling on 13 species of worms and found that the largest species were most heavily impacted. These creatures, called anecic earthworms, live deep down in the soil. At night-time they wriggle up a single channel, grab food, such as plant matter or manure, and then slide back down the same permanent burrow.
The researchers write that restoring earthworm populations through practing reduced-till or no-till farming “will ensure the provision of ecosystem functions such as soil structure maintenance and nutrient cycling by “nature’s plow.””
The Iowa Farm and Rural Life poll, managed by the Iowa State University Extension Sociology, was established in 1982 and is the longest running survey of its kind. This year’s survey was completed by 1,039 farmers, who were 65-years-old on average. The poll is sent to the same 2,000 farmers every year so that researchers can track changes over time. This year, it asked respondents about conservation techniques, farming practices, monarch butterfly population restoration and trustworthy information sources.
According to the poll, 42 percent of farmers surveyed practice no-till farming, which can be effective in reducing topsoil erosion. On average, farmers lose 5.8 tons of topsoil per acre per year which can lead to a loss of 15 bushels of yield per acre each year, according to the Corn and Soybean Digest. Buffer strips along water ways and field edges to filter nutrients and sediment from runoff was the most common conservation practice among respondents. Forty-six percent of farmers reported using buffer strips in 2015, while fewer than 40 percent reported implementing extended crop rotations, terraces, or ponds.
The survey also asked about participation in The Natural Resources Conservation Service (NRCS) programs. NRCS is the arm of the U.S. Department of Agriculture charged with the protection of natural resources on agricultural lands. It provides technical and financial support to farmers looking to conserve soil and water. More than 60 percent of farmers said that they were currently participating in an NRCS program, just about 34 percent said that they were not. For those not enrolled in NRCS programs, their primary reason was that they did not believe they had enough natural resources on their land to warrant participation.
The farm poll also analyzed which sources of agricultural advice respondents were most likely to trust. More than any other source, farmers said they would be most likely to trust another farmer that grows nearby.
The survey is collaborative project of Iowa State University Agriculture and Home Economics Experiment Station, ISU Extension Service and the Iowa Department of Agriculture and Land Stewardship. “Information from the Farm Poll is used to guide policy decisions and actions and as the basis for public policy seminars, Extension reports, radio and television broadcasts, and newspaper and journal articles,” reads the Iowa State University Extension site.
Students and researchers at the Iowa Flood Center (IFC) spent this summer working with NASA on a research project aiming to better understand and measure soil moisture.
The IFC team, based at the University of Iowa, is working to compare soil moisture data provided by NASA’s Soil Moisture Active Passive (SMAP) satellite with data gathered on the ground by IFC’s soil-moisture monitoring sensors. Researchers are specifically comparing soil moisture data from the South Fork watershed near Ames, a tributary of the Iowa River. IFC’s ground instrumentation provides real-time soil moisture measurements to farmers and researchers, while NASA’s satellite collects information in a different way. Put simply, the SMAP satellite views the Earth surface at a specific microwave-radiation wavelength that allows it to see through vegetation. The more water that is held in the soil, the darker it appears to the satellite. NASA is comparing this data against that which is measured on the ground by IFC to determine whether the water held inside of crops affects the accuracy of satellite imaging.
“As with many remote-sensing products, there is a continued need for evaluation,” says IFC Director Witold Krajewski. Validation of the satellite is a two part process. Researchers began by analyzing NASA’s satellite data from the end of May through early June, when crops were only beginning to emerge from the soil. During this first phase, IFC researchers and graduate students also set out to install and maintain soil-moisture instruments on the ground. They took a second look at soil moisture in early August when corn, soy, and other agricultural crops densely cover the ground in order to determine the satellite’s accuracy.
In addition to these measurements, IFC is taking a closer look the relationship between rainfall and soil moisture. The research team is using two mobile X-band polarimetric radars to study rainfall with increased temporal and spatial precision. IFC is also gathering data using several rainfall measuring tools provided by NASA. Krajewski explains, “Understanding the rainfall variability gives you an idea how much water gets into the soil and how it dries out.”
IFC is working with research partners at Iowa State University as well as those from universities and institutions across the country.
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.
A cover crop and soil health field day will be held in Solon, Iowa on Thursday June 16th to honor late farmer Tom Wall. A grower for 33 years, Wall practiced no-till agriculture on his corn and soy bean crops. In efforts to improve soil health, Walls also planted turnip and cereal rye cover crops beginning in 2013. Cover crops provide many benefits to the land, including soil erosion protection, reduced nutrient leaching, carbon sequestration, weed suppression, and integrated pest management.
The event will be held at the Timber Frame Lodge off of Lake Macbride Trail. It is hosted by the Iowa Learning Farms, in collaboration with the Rapid Creek Watershed Project and the Iowa Soybean Association. The event includes a complimentary dinner and is free and open to the public.
The field day will feature a discussion about “incorporating small grains and perennial forage into row crop rotations” led by Iowa State Extension and Outreach Agronomist Matt Liebman. Jason Steele, Area Resource Soil Scientist for Iowa Natural Resource Conservation Service, will conduct a demonstration on soil health. Additionally, attendees will have the chance to see the effects of rainfall on various agricultural and urban land use scenarios through a Conservation Station Simulator.
When considering that Iowa has lost over half of its topsoil over the last 100 years, events like these seem to carry a new significance. Beyond the devastating environmental consequences, there are also adverse economic effects of top soil erosion. In Iowa, eroded soil means rented land decreases in value by $6.74 per acre on average.
For more information about this cover crop and soil field day and other conservation education events, visit The Iowa Learning Farm.
PARIS – Experts from around the world weighed in on the importance of carbon sequestration and other sustainable agricultural practices during a conference Thursday morning.
The United Nations General Assembly declared 2015 “the International Year of Soil” which was the focus of the “Agroeology and Soil Solutions” conference in the Green Zone at COP 21. The event featured a four-person panel with each participant having expertise in a different aspect of agriculture or soil science. Before the panel gave their individual presentations, the approximately 50 attendees were shown a four-minute documentary produced by the Center for Food Safety and narrated by food journalist Michael Pollan.
“In one handful of soil there are more organisms than there are humans on earth and we are only beginning to understand the vast network of beings right beneath our feet,” Pollan said in the film’s opening scene.
The short film discussed the impact of over-farming and other unsustainable practices that remove carbon from the soil and release it into the atmosphere, contributing to rising temperatures and other effects of climate change.
Hans Herren – President and CEO of the Washington D.C.-based Millennium Institute – was the first panelist to present. Herren holds a PhD in Biological Control from the Federal Institute of Technology in Zurich, Switzerland and part of his presentation focused on the science behind carbon sequestration as he emphasized the need for dietary changes to improve soil health.
“If you don’t change the diet farmers can’t change the way they produce. People’s behavior in terms of diet is essential,” he said.
Kristine Nichols – Chief Scientist for the Pennsylvania-based Rodale Institute – was next to take the podium as she focused on research her center had done on a farm in Ohio. Nichols – who holds a PhD in Soil Science from the University of Maryland – said the carbon problem can actually be part of the solution.
“Really what we’ve got is a carbon problem and the problem is that we don’t have carbon in our soil.”
Nichols also addressed the negative effects of synthetic fertilizer and ways in which agriculture has become less efficient over the past half century.
“It takes more synthetic nitrogen fertilizer now to grow a ton of grain than it used to take in 1960,” she said. “Our systems are becoming far more inefficient because we’re not utilizing the biology.”
Nichols concluded her presentation with an interactive demonstration of the ability of different soils to retain water, showing that healthy soil can more easily retain moisture and filter excess liquid down to groundwater. Water retention not only helps soils to be more healthy but it also mitigates erosion and nutrient run off, both of which are concerns for farmers in Iowa.
The last of the panelists to speak was Precious Phiri, founder of the Zimbabwe-based EarthWisdom Consulting Co. Phiri focused on ways that grasslands, waterways, and livelihoods can be improved for African farmers and ranchers through better livestock management practices.
“We depend on livestock to get back our grasslands,” she said, adding “Overgrazing is an issue of time and not numbers.”
Phiri pointed out several examples in her homeland where proper grazing and agricultural techniques led to more permanent vegetation and waterways in the arid region.
The event concluded with a short question and answer session. During this time Nichols addressed the need for good research and the dissemination of information as well as strong policy that can lead to improved conditions.
“We needs to provide consistent and good information to people,” she said, adding “It is policies on the departmental level that would be beneficial.”
An Iowa City writer recently published an editorial in The New York Times outlining ways that Iowa is reducing and will continue to reduce carbon emissions.
Jeff Biggers – a writer-in-residence for the UI’s Office of Sustainability and founder of the Climate Narrative Project – points out efforts Iowa is currently taking to reduce its carbon footprint such as using wind power to generate roughly 30 percent of the state’s electricity needs as well as the WACO school district which soon hopes to generate 90 percent of its electricity from solar.
Biggers also discussed specific ways that an agriculturally-focused state such as Iowa can keep its carbon in the soil and out of the atmosphere. He points out that land misuse accounts for 30 percent of carbon emissions, a potential talking point for world leaders attending the COP 21 conference which begins later this month.
“Far too few climate change negotiators took notice of an important proposal called the Four Per Thousand Initiative, which France’s Ministry of Agriculture, Agrifood and Forestry introduced earlier this year. This proposal simply calls for a voluntary action plan to improve organic matter content and promote soil carbon sequestration in soil though a transition to agro-ecology, agro-forestry, conservation agriculture, and landscape management. According to France’s estimates, a “.4 percent annual growth rate for the soil carbon stock would make it possible to stop the present increase in atmospheric CO2.”
“We’re looking at soil carbon sequestration efforts through regenerative agriculture, through organic farming, through a whole host of activities that are happening now in the rural areas that really give me a lot of hope in terms of the climate change issue.”