Excess nutrients from farms can be transported to groundwater reservoirs by water starting at the surface and flowing through soil. But the flow of water through soil is a "highly dynamic process," says Genevieve Ali, a researcher at the University of Manitoba. "It can vary from year to year, season to season, or even rainstorm to rainstorm."
It can also fluctuate depending on soil type and even if organic additions, like manure, are applied.
Ali is lead author of a new study that shows water infiltrates deeper into cracking clay (vertisolic soils) when liquid hog manure is applied.
The study also showed that even though water infiltration went deeper in the presence of manure, it did not reach depths of 39 inches (100 cm). That's how deep tile drains–designed to remove excess subsurface water–are typically installed in the study region.
"This observation challenges previous studies, which showed that cracks in clay soils can promote the travel of water and associated contaminants from the soil surface into tile drains," says Ali. "Our study suggests that not all clay-rich soils behave the same."
The researchers focused on vertisols because they are present in large regions of North America. "They are common in agricultural plains, where excess nutrients may be common due to intensive farming," Ali says.
But knowledge gaps remain about soil water flow in vertisols, especially with organic additions.
Water can flow through soil in different ways. 'Matrix flow' occurs when water moves slowly through tiny spaces between soil grains. 'Preferential flow' takes place when water travels relatively quickly through bigger channels, called macropores, such as cracks and earthworm burrows.
"Imagine a bucket of sand with plastic straws inserted throughout," says Ali. "If you dumped water on this sand bucket, the water traveling through the straws would reach the bottom first."
Similarly, preferential water flow through soil macropores can carry contaminants quickly from the surface down to groundwater reservoirs.
Macropores are often connected to one another. "They act like a network of pipes, and they can be created or exacerbated by human activities," says Ali. "Knowing when and where there is preferential flow and how to manage land in those areas is critical to preserving groundwater quality."
Clay-rich soils--such as vertisols–tend to crack, which creates macropores. "That makes these soils natural candidates to study the relative importance of matrix and preferential flow," says Ali.
This study was conducted in research plots in Manitoba, Canada. Researchers added liquid hog manure to one plot but not the other. They sprinkled water mixed with blue dye on both plots to determine how water moved through the soil.
In the plot where manure was applied, water reached up to 25 inches (64 cm) into the soil. In contrast, water reached up to 18 inches (45 cm) in the plot where manure was not applied. Both plots showed evidence of matrix and preferential water flow.
The researchers also found that the water moving through the macropores was not completely separated from the rest of the soil.
"If you think back to the analogy of the sand bucket with the straws in it, the straws have a bunch of small little holes in them," says Ali. "Water can be exchanged laterally between the macropores and the surrounding soil."
Lateral exchange has been reported frequently for smaller macropores in forested soils, says Ali. "But it is less common in agricultural soils where cracks tend to be larger."
This study focused on a single site, so Ali says that further research is needed before generalizations can be made.
Ali is also studying the role of soil cracks in spring (created by the soil freezing and thawing multiple times) versus the role of cracks in summer (created when soils become especially dry).
Read more about this research in Agricultural and Environmental Letters. The research was done under the umbrella of the Watershed Systems Research Program and funded by the Government of Manitoba, as well as a Natural Sciences and Engineering Research Council Discovery Grant awarded to Genevieve Ali.
Dirty cows usually mean a dirty tail, and dirty tails can come from dirty stalls. Since the ban on tail docking of dairy cattle, managing manure for cow hygiene is as automated as it has ever been.
"Automated alley scraper systems have been successfully used on livestock farms for decades to keep freestalls and cows clean," said Andy Lenkaitis, GEA product manager for manure equipment. "I work with many farmers who produce high-quality milk and have cows with long tails. They make management of their automated alley scraper systems a priority to avoid tail entanglement or animal injury." | READ MORE
The operation has also agreed to reimburse the Indiana Department of Natural Resources $1,775 for the value of damage to fish and wildlife.
The Indiana Department of Environmental Management says the lagoon was filled beyond capacity and overflowed into a field tile that led to Fountain Creek, causing the death of more than 3,500 fish on April 3, 2017. | READ MORE
Years ago, it was tradition for farmers to grow a variety of crops on their farm. There was limited food distribution to large grocery stores, and most of the food was grown locally. So, a farmer could be cropping cotton and sweet potatoes in one area of their farm. On another area, graze beef cattle, dairy, or chickens on forage crops like annual clovers, perennial tall fescue, wheat pasture, and native rangeland.
Pastures and hayland were rotated with crops so that the same enterprise was not on the same field year after year. Diversity of enterprises on each farm helped create stability in the production system.
With the advent of large farming equipment and commercial fertilizers following World War II, it became more efficient from a labor standpoint to grow the same types of crop year after year.
After investing in equipment to handle a particular crop like corn, farmers often became more specialized. This led to monoculture cropping, which can have positive effects on yields and efficiency. But, monoculture has some drawbacks, including environmental and social concerns.
The need for greater nutrient inputs with monoculture can lead to poor water quality underground or from run-off. Confined operations have the issue of disposing of large volumes of manure.
Interest in re-integrating farms to take advantage of the synergies between crops and livestock has increased in the past few decades. Our lab has embarked on researching such integrated systems as a way to improve agricultural sustainability.
Crop-pasture rotations are part of an integrated system. Farmers can match the energy and nutrient flows of different enterprises (i.e. types of livestock and types of crops) to meet the desired outcomes.
Ruminant livestock consume forages, often on pasture by themselves during much of the year. Animal manures are deposited directly on the land where they graze. Alternatively, they can be confined in areas during parts of the year with conserved forages, e.g. hay or silage.
Manures can also be collected from confinement areas and applied to cropland. This recycles and effectively utilizes nutrients throughout the entire system and can substantially reduce chemical fertilizer needs for cropping.
Forage grasses used for grazing often have extensive, fibrous root systems. These roots hold soil particles together. All plants take carbon dioxide from the air and convert it into simple sugars during photosynthesis.
Compared with annual crops, forage grasses form a thick mat over the soil, and can enrich the amount of carbon in soil more than annual crops. Forage legumes are capable of converting nitrogen from the atmosphere and add nitrogen to the soil as well.
The large gain in soil organic carbon under perennial pastures is a key benefit of integrated crop-livestock systems.
Pasturing is also an important adaptation strategy to overcome drought. Pastures can partially control flooding by improving water infiltration and soil health. Forage and grazing lands have historically provided a sustainable and resilient land cover. Grazing lands are rooted by a variety of grasses and forbs that serve to provide essential ecosystem services:
- Water cycling
- Nutrient cycling
- Gas exchange with the atmosphere
- Erosion control and landscape stabilizing
- Climate moderation
- Food and feed production, and,
- Aesthetic experience
Integrated agricultural systems have the potential to adapt to weather extremes. This can make them more climate-resilient than monoculture systems. For example, integrated crop-livestock systems rely on forages as part of a diversity of crop choices. These forages provide a large benefit for positive balance of carbon stored in soil. Crops grown in rotation with forages can be more profitable, since yields are often enhanced and costly fertilizer inputs can be lower. The presence of forages can reduce nutrient runoff and reduce nitrous oxide emissions.1
The diversity of farming operations in integrated crop-livestock systems reduces the overall risk of failure. By having several different crops on a farm, the risk of any one component failing is reduced.
This diversity also offers resilience of the farming system against extreme weather events and potential climate change. Greater integration of crops and livestock using modern technologies could broadly transform agriculture to enhance productivity.
Integrated crop-livestock systems can also reduce environmental damage, protect and enhance biological diversity, and reduce dependence on fossil fuels.
Integrated systems likely provide healthier potentially more diverse foods and increase economic and cultural opportunities in many different regions of the world.
Diverse agricultural systems that include livestock, perennial grasses and legumes, and a wide variety of annual forages offer enhanced agro-ecosystem resilience in the face of uncertain climate and market conditions.
Indeed, there are many good reasons why a diversity of crops and livestock should be produced on the same farm and even the same field within a farm.
"This grant highlights the power of state and federal governments working in partnership to protect the natural environment," said EPA regional administrator, Cosmo Servidio. "Providing these funds directly to Delaware empowers the state to address its unique and critical environmental challenges."
"Over the years, there has been vast improvement in the water quality in Delaware, but challenges still persist," said Delaware Department of Natural Resources and Environmental Control secretary, Shawn M. Garvin. "DNREC appreciates the ongoing partnership and funding support from EPA. This grant will support investments in cover crops, nutrient management, the Conservation Reserve Enhancement Program (CREP), stormwater retrofits, and tree planting projects that will enhance and improve water quality statewide."
The funding is provided under Section 319 of the Clean Water Act, which authorizes EPA to provide grants to states to implement nonpoint source pollution control programs. It will support Delaware's nonpoint source management program, focusing on watersheds with water quality impairments caused by polluted runoff.
These nonpoint source control projects include a variety of structural and non-structural best management practices, monitoring, and technology demonstrations. The funding will also support outreach activities to educate the public about nonpoint source pollution.
Nonpoint source pollution is caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up and carries away pollutants, depositing them into lakes, rivers, wetlands, coastal waters, and ground water. Sources of nonpoint source pollution include urban runoff, agricultural runoff, and changes to natural stream channels.
Congress enacted Section 319 of the Clean Water Act in 1987, establishing a national program to control nonpoint sources of water pollution. Section 319 enables EPA to provide states, territories, and tribes with guidance and grant funding to implement their nonpoint source programs and support local projects to improve water quality.
Since 2005, this work by states has restored more than 550 impaired waterbodies nationally, which includes more than 200,000 acres of lakes and more than 10,500 miles of rivers and streams. Hundreds of additional projects are currently underway across the country.
Learn more about successful nonpoint source projects at https://www.epa.gov/nps/nonpoint-source-success-stories.
Saving money time and resources by pumping your manure to your site location through a hose can be the solution you are looking for.
Attendees will learn the latest information from the Ohio Department of Agriculture regarding changes to nutrient management regulations.
In order to provide tools to deal with manure management, Rob Clendening with the Knox County Farm Bureau/SWCD will give a presentation about the OnMrk app for nutrient tracking and record keeping.
Likewise, Dr. Libby Dayton will demonstrate the OnField! app, which explains the new Phosphorus Risk Index and what it means to producers. These tools will help farmers be proactive and informed about the risks associated with nutrient management.
Pizza and drinks will be provided at no cost. Pop and popcorn will be available for purchase at the theater. RSVP to this free event by Aug. 27 by calling Ashland SWCD at 419-281-7645. Any questions can be directed to Ashland SWCD or Holmes SWCD at 330-674-2811, ext. 3.
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Subsurface Drip Irrigation using dairy manure field tourThu Aug 22, 2019
World Dairy Summit Mon Sep 23, 2019
BioCycle REFOR19Mon Oct 28, 2019
2019 Sustainable Agriculture SummitWed Nov 20, 2019