The Tree
T h e U W D i s c ove r y Fa r m s N e w s l e t t e r
Spring 2014
DEPTH TO BEDROCK MAPPING WORKSHOP A SUCCESS Kevan Klingberg
Depth to bedrock is an important factor to consider as we conduct farm business on top of the soil; over the top of local landscapes and geology. Some Wisconsin locations have bedrock at more than 50 feet deep; other areas have bedrock that can be found just beneath the soil surface with a poke or two of a pointed shovel. Sandstone, limestone and granite are all common bedrock materials found in Wisconsin. Sandstone and granite are usually solid and, in concert with soil sitting on top of them, are protective of groundwater in aquifers below. However, limestone, also referred to as carbonate bedrock, is often fractured and broken, providing less protection to groundwater below. Depth to bedrock and bedrock composition are important characteristics relative to the water cycle and groundwater quality. As precipitation percolates into and through the soil, the chemical, mineral and organic properties within soils slow or grab onto some of the nutrients traveling with soil water. Once the downward movement of soil water reaches shallow-fractured bedrock, it can continue quickly and unimpeded toward continued on page 4
INSIDE
Depth to Bedrock Mapping Workshop a Success................... 1 Conservation Observations from Whole Farm Walkovers. ................................................................................................. 1 Bunker Silo Leachate Study Update................................... 4 Notes from the Nitrogen Summit: The Unseen Nitrogen............................................................. 6 Interns to Conduct Stream Water Sampling..................... 7
A waterway that needs shaping to allow runoff water in.
CONSERVATION OBSERVATIONS FROM WHOLE FARM WALKOVERS Todd Prill
What is a Whole Farm Walkover? n the spring of 2012, Discovery Farms started working with farmers in the Jersey Valley and Dry Run watersheds to verify, document and better understand the effectiveness of their farming system, their conservation practices and their soil fertility programs through a process called Whole Farm Walkovers. The first step in this process is to walk over the land (farmed and unfarmed)
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Co-Director’s Column Happy Spring and Early Summer! We’ve survived yet another Wisconsin winter. This one gave us a good dose of snow, cold, and was just plain long. Spring didn’t start out very fast, but at least our field work is ahead of last year’s schedule. At Discovery Farms, we had an exciting winter. We kicked it off with our annual conference, filled with great discussion and wonderful attendees. In the months after that, we talked about this year’s monitoring results with many different groups in 42 different presentations over 4 months, wrote some pieces on winter manure application, held meetings for our watershed farmers and community members, and summarized our leachate and edge of field monitoring data for the year. In addition to all of those regular winter activities, we also took applications for a new core farm project in Southeastern Wisconsin. We put out the call for farms to apply in Rock, Jefferson, and Dodge Counties. The specific intent of the new project is to collect additional data in Southeastern Wisconsin’s landscape, learn more about nutrient and sediment loss from grain systems, further our understanding of tile drainage and gain some insight on the benefits of precision farming practices for nutrient application. Farms of all types and sizes applied. In April, we were able to meet with the farmers that applied and survey the farms for potential monitoring sites. What a great group of farmers! We are planning to partner with NRCS on this project, so we are currently further analyzing which sites would work for potential tile, surface, and stream water quality monitoring. Some of the sites will be installed this summer or early fall. We will be announcing the new farms and hosting a kickoff event this summer, so watch for the announcement! We are really looking forward to working with this new group of farms while we continue to understand the impact of agricultural practices on water resources. Until next time, have a safe spring season. Here’s hoping for no corn planted in July this year! Amber Radatz
2 The Tree-Spring 2014
Farm Walkover for Soil & Water Management
Dry Run Watershed Walkover Progress January 27, 2014 0
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What has Discovery Farms found during the walkovers? As of this writing, about 60% of the total land in the Dry Run Watershed has been evaluated (see map). This land includes over 9 miles of intermittent stream and 10 miles of waterways. Some initial observations:
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with the farmer to ensure that the evaluation identified all of the critical areas on the farm. Areas that need improvement are discussed and strategies are developed to secure additional assistance, where necessary. Farmers appreciate this effort and provide constructive feedback on the format and content of the assessment.
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99 Several areas of the natural stream corridors have moderate to severe bank erosion.
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What’s Next? Discovery Farms staff has set a goal of finishing Whole Farm Walkovers this fall. It is anticipated the information gathered from the Whole Farm Walkovers will be summarized and presented back to farmers next year. Discovery Farms also has a financial incentive available for soil and water conservation practices that protect and improve critical areas identified through the whole farm walkover process. Please contact Todd Prill at 715.225-0862 for assistance. §
and identify areas that may contribute nutrients and sediment to area streams and lakes. Critical areas get color coded to prioritize land areas where the risks of nutrients and/or sediment loss are acceptable, improvable or unacceptable: 99 Green – excellent or very good level of management (no changes required) 99 Yellow – areas that need some improvement over a period of 1 – 5 years
DF EVENT
99 Red – areas that need improvement within the next 12 -18 months After walking farms, a map identifying the location and color coding of critical areas is developed. In addition, Discovery Farms staff complete a short text summary that documents beneficial practices farmers are using to protect water quality. This information then is shared 3
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Two summer field days are being planned to feature nutrient use efficiency, Willow River and/or West Fork Kickapoo River stream water sampling, and more . These will happen in late August near Baldwin, and near Cashton, WI. Watch for more details on our Facebook page or by subscribing to our e-updates!
BUNKER SILO LEACHATE STUDY UPDATE Aaron Wunderlin
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n 2012, Discovery Farms implemented a study to monitor feed storage leachate. Cooperation from three farms has allowed Discovery Farms to monitor leachate at the collection point on the edge of the bunker pad. The goal is to better understand how concentrations and loads of various constituents leaving the bunker area change over time – storm volume and intensity, stored feed types and quantities, and seasonal influences on leachate constituents. With this knowledge, Discovery Farms will assess the effectiveness of
the current collection systems and determine additional options for managing leachate. Data collection has been a challenge with installing monitoring equipment on diverse leachate systems, calibrating equipment, and fighting the elements. Keeping the equipment maintained and working properly is very labor intensive. Despite all this, good data have been collected in 2012 and 2013. Much has been learned with this data, and future data will help in understanding what happens at the end of the bunker pad. One thing is for sure, preliminary review of the data seems to suggest leachate runoff and timing is more complex than what “first flush” implies. The feed storage leachate monitoring project is now in its third and final year. At the end of this year, equipment will be shut down and the final analysis of the data will begin. Once analyzed, a final report will be released with the findings. The information learned from this study will aid in future leachate system designs to more efficiently collect nutrients from feed storage, thus reducing the volume of liquid that is collected and needs to be sent to manure storage or other collection systems. In addition, data from this study should foster increased design options for farmers and decreased leachate system costs. §
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Depth to Bedrock Mapping Workshop a Success the upper layer of groundwater. This is especially important as farmers manage soils, crops, and nutrients in localities where carbonate bedrock is close to the surface with less soil to act as a filter. Figure 1 shows areas in Wisconsin where carbonate bedrock is typically 50 feet or less beneath the land surface. When carbonate bedrock is the uppermost bedrock unit it can begin to dissolve over time with the natural acidity of rain and cause fractures to enlarge. The fractures, sinkholes and other breaks in the bedrock integrity as a result of this dissolving action are referred to as karst features. Traditional methods to determine bedrock depth include digging large holes with heavy equipment. Recent improvements in electronics and computing power have made it possible to electronically estimate 4 The Tree-Spring 2014
Figure 1. Carbonate bedrock locations in WI.
along a 225 ft. transect line. The electrical pulse is echoed back based on the resistance it meets, which is calibrated to define material density and depth. Figure 2 shows an Electrical Resistivity Imaging transmitter attached to a transect wire with spaced probes. Participants were told that the electronic hardware and computer software used in the demonstration costs approximately $15,000, and that some local agencies are considering buying this technology to share. We thank Gold Star Farms of New Holstein, WI, and Heisner Family Dairy of Mineral Point, WI, for hosting these afternoon field sessions.
Figure 2. ERI transmitter with transect and spaced probes.
bedrock depth in the field, and then dig smaller and more targeted confirmation holes only as needed. In late April, the Wisconsin Geological and Natural History Survey (WGNHS) and University of Wisconsin Discovery Farms Program conducted two workshops highlighting emerging technologies in mapping soil subsurface characteristics and depth to bedrock. The targeted audience was conservation and agronomy technical service providers, land and water conservation professionals, and engineers. The workshop consisted of a classroom portion in the morning, and field demonstrations in the afternoon.
Figure 3 is the resulting Electrical Resistivity Image of the soil subsurface in a pasture at the Heisner farm. For this activity a transect wire was laid in a pasture, running uphill from a flatter wet area next to a stream towards a quickly raising 9-12 % sloped hill. The blue area (A) is inferred to be wetland sediments. These sediments contain more water, and are more conductive (less resistive). The green and aqua colored area (B) is inferred to be hill-slope sediment. These sediments are drier and more competent than the wetland sediment, making them more resistive. The red, orange and purple colored areas (C) are inferred to be bedrock. Bedrock is more competent than the overlaying sediment. This ERI exercise took 1 hour to complete; was done with equipment carried to the field in a 20 gallon tote; and estimates bedrock to be between 3-6 feet deep beneath the wetland and lower end of the hill, and within inches of the soil surface further up the hill.
Information was presented twice; once in Chilton, and again in Dodgeville, Wisconsin. Workshop topics included 1) Local perspectives on challenges with bedrock and soil subsurface characteristics; 2) How to create multi-layer depth to bedrock maps with existing information; and 3) New technologies to help identify what is under the soil surface. The featured technologies included Electrical Resistivity Imaging (ERI), ArcMap database management and use of a Geoprobe.
This technology continues to develop and improve quickly. A set of factsheets and materials on mapping depth to bedrock can be found on our UW-Discovery Farms website: http://www.uwdiscoveryfarms.org/OurResearch/ManureManagementConsiderations/MappingBedrock.aspx. If there is interest in similar trainings throughout Wisconsin, please contact us. As always, call our office at 715-983-5668 or e-mail our staff with questions you may have. ยง
Each afternoon session was spent on a local farm where the WGNHS staff demonstrated a relatively simple way to estimate depth to bedrock using Electrical Resistivity Imaging (ERI). The general concept with ERI is to send small electrical currents into the soil at 10 ft. intervals
Figure 3. ERI transect image through Heisner pasture. 5 The Tree-Spring 2014
NOTES FROM THE NITROGEN SUMMIT: THE UNSEEN NITROGEN Matt Ruark, UW-Madison, Department of Soil Science
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he most common problem for farmers and crop consultants when determining an optimal nitrogen (N) rate for corn is that they never truly know if and by how much they “over” applied their N fertilizer. Underapplication of N is readily seen in corn plants through classic N deficiency symptoms of yellowing of the midrib on lower leaves, likely resulting in reduced yields (http://www.agronext.iastate.edu/soilfertility/photos/ photossdef.html). There are a few metrics used to determine if N was over-applied, such as the corn stalk nitrate test (https://store.extension.iastate.edu/Product/ pm1584-pdf) and end-of-season soil nitrate test. These tests require extensive sampling, only pertain to corn, and the relationship between stalk or soil nitrate values and crop yield are not well documented in Wisconsin. What I suggest here is the use of nitrogen use efficiency (NUE) calculations as simple metrics that can be used to understand how efficient you are (and can be) with N fertilizer.
applied; if it is negative, more N was removed than what was applied. If it is positive, this is the amount of N remaining in the soil system. However, a lot of this N can still be tied up in the crop residue and for many systems there is a limit on how close we can get this value to 1. More accurate PNB values can be determined if the actual N concentration of the grain is known. The value of the zero-N check strip. To get a sense of how much N is available from the soil, we can use the amount of N taken up by the corn plant (ears, stalks, and leaves – the entire above ground biomass) when no fertilizer is applied. This will involve cutting a whole plant at ground level, drying, and analyzing for total N; this is obviously not a standard sample practice. This value (total N uptake in unfertilized corn) can then be subtracted from the N in the above ground biomass from fertilized corn and then divided by the amount of N applied to give us the apparent crop recovery efficiency (RE). It is called the “apparent” crop recovery efficiency because we aren’t using the N taken up in root biomass and we are making assumptions about the fate of the applied N. In this case a value of 1 would indicate that the increase in N uptake from unfertilized to fertilized was the same as the amount of N applied (this is an unrealistic system). Snyder and Bruulsema (2007) provide some context, stating that values of 0.5 to 0.8 represent corn systems under best management practices. So, the value of the zero-N check strip allows you to know how much of your N was “needed” by the crop. This is in contrast to the partial nutrient balance calculation, which doesn’t indicate anything about crop need of the fertilizer, only the N balance of your soil and cropping system.
The partial nutrient balance. One way that farmers and crop consultants can “see” the unused nitrogen is through nitrogen use efficiency calculations. There is no one specific calculation that is the true NUE, but instead the term NUE represents a suite of calculations that each have a specific meaning. The simplest calculation is the partial nutrient balance (PNB), which is the amount of N removed in the grain divided by the N applied (http://go.wisc.edu/1467hc). A PNB of 1 (or slightly less) is considered ideal (i.e. system sustainability). If the value is much less than one, then this indicates there are opportunities for improvement. The PNB is a calculation that can be done by all growers on a field-by-field basis as long as they know their yield and the amount of N applied. Based on average N concentrations from corn samples analyzed at the University of Wisconsin Soil and Plant Analysis Laboratory, 0.70 lb-N is removed with 1 bu of corn grain (at 15.5% moisture). Therefore, multiplying 0.70 by the yield (bu/ac) gives an estimate of the amount of N removed. This calculation can also be used to “see” a simple N budget for the field (N input vs. N output) by subtracting the N removal from the N 6
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Recovery efficiency verifies the need of the fertilizer. Different soils will supply different amounts of N. For example, in an N rate trial conducted in 2011, corn fertilized with 150 lb/ac of N at the Lancaster Agricultural Experiment Station had a RE of 63% while corn grown at the Arlington Agricultural Experiment Station had a RE of 28%. This indicates that we would want to think about altering our N rates at Arlington because less than 30% of the N that was applied was taken up. At Lancaster, we may not be able to improve much as nearly 70% of the N applied was takenup by the plant.
leading to RE of 88%, while the PNB was only 43% (150 lb/ac of N was used in this example). The 43% PNB is quite low, indicating a lot more N is applied to the system than is removed. However, a large percentage of the N applied ended up being taken up by the crop. Thus, for sweet corn on sandy soil, the PNB alone doesn’t tell the whole story regarding efficiency and fate of the N applied. Overall, you’ll notice that I’ve used a lot of terms like “estimate” and “apparent” throughout the past few paragraphs. These calculations are not meant to be the last word on how efficient you are with your N fertilizer, but simply provide a tool for farmers and crop consultants to assess the current state of their N management. These measures need to be conducted across many growing seasons to get a range of efficiency values across different rainfall patterns. But, if we can make the “unseen” nitrogen “seen”, this will give both farmers and consultants more confidence with continuing their current N management plan or identify fields on which improvement strategies are warranted.
Another useful comparison is between the RE and the PNB. A stark contrast between these two calculations can be seen with irrigated sweet corn in the central sands in 2011. Yields without N were incredibly low,
For more information on nitrogen use efficiency calculations see http://go.wisc.edu/1467hc. For more general information on nitrogen in soil check out Soil and Applied Nitrogen (http://www.soils.wisc.edu/extension/ pubs/A2519.pdf). §
INTERNS TO CONDUCT STREAM WATER SAMPLING Juel Gunderson
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his summer the Discovery Farms Program is fortunate to have two UW-River Falls college students conducting internships based on our watershed work. Sam Hess is a sophomore from Whitehall, WI, majoring in Environmental Science. Juel Gunderson is a junior from Pigeon Falls, majoring in Conservation. Aaron Wunderlin, our Discovery Farms research specialist, is supervising their special project, a field study to evaluate stream water quality. Both Sam and Juel will work on their own set of 4-6 sites in either the Willow or Jersey Valley Watersheds. They will learn and use stream water sampling techniques defined by the Water Action Volunteer Program, a partnership between the WI DNR and UW-Extension (http://watermonitoring.uwex.edu/wav/).
Stream water in both locations will be evaluated for a variety of conditions necessary for healthy and productive fish reproduction. Testing parameters will include temperature of water and air, water transparency (clarity), stream flow, habitat assessments, depth, pH, and a biotic index. These measurements help define how healthy the streams are as fish habitat. § 7 The Tree-Spring 2014
PIGEON FALLS, WISCONSIN 54760 NONPROFIT ORG. U.S. POSTAGE
PAID
University of Wisconsin
PERMIT NO. 2
Cooperative Extension Trempealeau County Discovery Farms PO Box 429, 40195 Winsand Drive Pigeon Falls, WI 54760-0429
Return Service Requested
For more information and to stay connected:
facebook.com/uwdiscoveryfarms fyi.uwex.edu/discoveryfarms twitter.com/DiscoveryFarms youtube.com/DiscoveryFarms This newsletter can be found on the web at: www.uwdiscoveryfarms.org Regarding the mailing list, call/e-mail 715-983-5668 or jgoplin@wisc.edu.
Co-Directors Eric Cooley 608-235-5259 etcooley@wisc.edu Amber Radatz 608-317-0001 aradatz@wisc.edu Faculty Advisor Matt Ruark 608-263-2889 mdruark@wisc.edu Outreach Specialist Kevan Klingberg 715-983-2240 kevan.klingberg@ces.uwex.edu Program Assistant Judy Goplin 715-983-5668 jgoplin@wisc.edu Research Specialist Aaron Wunderlin 920-839-5431 aaron.wunderlin@ces.uwex.edu Dry Run Watershed Coordinator Todd Prill 715-225-0862 discovery.farms.prill@gmail.com Interns Sam Hess samhess31@gmail.com Juel Gunderson juelgunderson54@gmail.com
UW Discovery Farms is a producer-led research and outreach program based out of the University of Wisconsin-Extension. The program is unique in that it conducts research on working farms located throughout Wisconsin, seeking to identify the impacts of production agriculture on water quality. The program is managed by faculty from the University of Wisconsin, along with oversight from a steering committee of producers, citizens and agency personnel representing a wide variety of non-profit and government organizations. Funding has been provided by the State of Wisconsin, UW-Extension, as well as a number of annual grants from producer groups and our federal partners. An EEO/Affirmative Action employer, University of Wisconsin-Extension provides equal opportunities in employment and programming, including Title IX and ADA requirements. Request for reasonable accommodation for disabilities or limitations should be made prior to the date of the program or activity for which it is needed. Publications are available in alternative formats upon request. Please make such requests as early as possible by contacting the Discovery Farms office at 715-983-5668 so proper arrangements can be made.