What we can learn when we come together

Post written by Hanna Bates, Program Assistant at the Iowa Water Center

The agriculture community is a vast network that includes farmers, researchers, coordinators, agronomists, and more. Whether we are in the lab or out in the field, we all have one person in common – the farmer. According to a study by Doll and Reimer in the Journal Extension, many public and private professionals interact with farmers to guide on-farm decision making, but rarely do these individuals effectively interact with each other. When these individuals do work with each other, the research indicates it could be substantial for their knowledge and understanding of nutrient management.

In this study by Doll and Reimer, researchers invited Extension educators and private sector nitrogen dealers from across the Midwest for a 1.5-day workshop to discuss the many aspects of nitrogen fertilizer, including the biophysical and the social. The workshop goal was to inform management and policy decisions and to encourage future research and educational partnerships on nutrient management (Doll and Reimer 2017). The workshop included a myriad of topics and formats that involve small group sessions using flip charts to farmer panels to large group discussions. Of those who came to the workshop, 96 percent advised farmers on nutrient management as part of their jobs (Doll and Reimer 2017). Nutrient management on the farm plays a critical role in influencing local water quality as well as contributes to water impairments in the Gulf of Mexico hypoxic zone.

The researchers in this study reported, “96 percent of participants said that a mix of presentations and discussions provided an effective means for learning about nitrogen management” (Doll and Reimer 2017). Ninety-percent of respondents indicated that they improved their understanding of diverse viewpoints on nitrogen management during the workshop (Doll and Reimer 2017). Not only this, but they also improved their knowledge of available tools for decision-support in efficient nitrogen management. These are key findings given that there are many diverse approaches and viewpoints when it comes to policy decisions. Best of all, 90 percent would recommend this workshop to a colleague, and a majority of participants had increased “motivation to implement knowledge in the area of sustainable nitrogen management” (Doll and Reimer 2017).

Most respondents also indicated that they have never met each other prior to the workshop. These relationships are vital since each can have an influence on a farmer’s nutrient management decision-making. Regardless of the role you play, you are valuable to the agricultural outreach system. If you are a researcher, think about the wider influences of your research. If you are in the private sector, it is key to be learning continuously and to help clients make the best decision for resilient farm operations using the best data available.

It may seem like there is an ever-increasing number of meetings, conferences, summits, and workshops that are available in Iowa for researchers, coordinators, and farmers alike. We should not take that time for granted. Rather, we should appreciate having the time to get to know our community in water and to kick around new ideas with new people. I am inspired by the research from Doll and Reimer that if you can execute an event well with a diverse range of people, you can make a huge positive impact on water resources.

Doll, Julie and Adam Reimer. 2017. Bringing Farm Advisors into the Sustainability Conversation: Results from a Nitrogen Workshop in the U.S. Midwest. Journal of Extension 55(5) https://www.joe.org/joe/2017october/iw2.php.

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Hanna Bates is the Program Assistant at the Iowa Water Center. She has a MS in Sociology and Sustainable Agriculture from Iowa State University. She is also an alumna of the University of Iowa for her undergraduate degree. 

Summer Update from the IWC Graduate Student Research Grant Program: Nathan Young

Post submitted by Nathan Young, a PhD student co-majoring in Geology and Environmental Science here at Iowa State University.

Over the past 30 years, computer simulations of groundwater flow have become a standard tool for investigating water quality and quantity issues across the globe. Because of a number of limitations, ranging from data availability to available computer power, these simulations (or “models”) contain a number of simplifying assumptions that prevent them from being perfect representations of the location being studied. For instance, if the subsurface was composed primarily of sand with some gravel mixed in, we may tell the model that the subsurface is only composed of sand to simplify the model and make it run faster. While these assumptions may be acceptable under most circumstances, several common assumptions made about the subsurface in Iowa may in fact impede our understanding of how water and nutrients are moving throughout the state. In Iowa’s till dominated watersheds, the subsurface is commonly treated as a fairly homogenous low-permeability material, while in reality, ultra-small-scale cracks (or fractures) present in this material provide pipe-like pathways through which water and nutrients can move very rapidly. These fractures are often omitted from models due to the massive amount of computer power required to include them in the type of watershed-scale investigations that would be conducted for the purposes of evaluating regional water quality.

In spring 2017, I was awarded funding in the Iowa Water Center Graduate Student Supplemental Research Competition for my project titled, “Simulation of Watershed-Scale Nitrate Transport in Fractured Till Using Upscaled Parameters Obtained from Till Core.” My research seeks to accomplish two goals: to develop a method to include fractures in watershed-scale models, and then to evaluate the extent to which these ultra-small-scale fractures enhance groundwater flow and nutrient transport at the watershed scale.

This past summer I have made significant progress on my project on a number of fronts. My laboratory experiments on a series of 16x16x16 cm sediment samples excavated from the Dakota Access Pipeline trenches are ongoing, but they are progressing forward. I am currently conducting flow experiments on the samples using groundwater spiked with a chemical tracer. These samples contain small-scale cracks, called fractures, which provide pathways for very rapid movement of fluid and tracer in what would otherwise be a largely impervious material. By measuring the flow rate of fluid coming out of the sample, as well as the concentration of tracer that this effluent contains, I can quantify to what degree these fractures are enhancing flow within the sample. Early results of this work show that as we move deeper in the subsurface, water moves through the samples more slowly (which is what we would expect to see) yet these flow rates are still higher than we would find if the samples did not contain fractures. Furthermore, tracer concentrations in the sample effluent indicate that the fractures are providing preferential pathways for the tracer to flow through, resulting in tracer exiting the sample much sooner than if it were unfractured. I have been fortunate to have the assistance of two undergraduates, Jay Karani ’19, and Kate Staebell ’17, in setting up these experiments and analyzing the resulting output. This work would have taken much longer without their help!

I have also been working to develop a set of new computational methods that will allow for the role that these fractures play in groundwater flow and solute transport to be included in watershed-scale computer models. Previously, accounting for groundwater flow in fractures was too computationally intensive to include in models larger than the size of a small field. Yet the early results of my work suggest that we may have found a method to circumvent this computational limitation by computing a new set of flow parameters using sophisticated, small-scale groundwater flow simulations and field data.  I presented some preliminary results of this work at the 2017 MODFLOW and More conference in Golden, Colorado, this past May, and was awarded 2nd place for graduate student presentations. A short paper on this work was also published in the conference proceedings. I am currently finalizing my results in preparation for a talk I will be giving at the Geological Society of America’s National meeting in Seattle later this month. I am also in the process of writing up the results for publication, and hope to have one of two manuscripts ready for submission by the end of the semester.

Finally, I was invited to visit Laval University in Quebec City, Canada this past August to work with Dr. René Therrien, a professor in the Department of Geology and Geological Engineering who developed the groundwater model I am using in my research. With the help of Dr. Therrien and his research group, I was able to accomplish in two weeks what would have likely taken me three months on my own. I have already been invited back to work with them again in summer 2018. We are working together to write a grant proposal to secure funding for that visit. I am confident that continued work with my collaborators at Laval University will enable me to include more detail in my study area, Walnut Creek watershed, into the overall model of the watershed I am currently building.

Get to know your soil

Photos of the 2017-2018 Agronomy in the Field cohort for Central Iowa at the ISU Field Extension Education Lab. Photos by Hanna Bates.

An education in soil sampling

Last week I attended Agronomy in the Field, led by Angie Reick-Hinz, an ISU field agronomist.  The workshop focused on soil sampling out in a field. The cohort learned a lot of valuable insight into not only the science of soil sampling, but also practical knowledge from out-in-the-field experiences.

Taking soil samples in a field is critical in making decisions about fertilizer, manure, and limestone application rates. Both over and under application can reduce profits, so the best decision a farmer can make is based on a representative sample that accurately shows differences across his/her fields.

What do you need?

  • Sample bags
  • Field map
  • Soil probe
  • Bucket

When do you sample?

After harvest or before spring/fall fertilization times. Sampling should not occur immediately after lime, fertilizer, or manure application or when soil is excessively wet.

Where do you sample?

Samples taken from a field should represent a soil area that is under the same type of field cultivation and nutrient management. According to ISU Extension, the “choice of sample areas is determined by the soils present, past management and productivity, and goals desired for field management practices.”* See ISU Extension resources for maps and examples for where in the field to take samples.

Most importantly…

Like with everything that happens out in the field, it is important to keep records on soil testing so that you can evaluate change over time and the efficiency of fertilizer programs. As we say at the Iowa Water Center, the more data, the better! The more we learn about the soils, the better we can protect and enhance them. Healthy soils stay in place in a field and promote better crop growth by keeping nutrients where they belong during rain events. Not only can we monitor soil from the ground with farmers, but with The Daily Erosion Project. These combined resources, with others, can provide the best guidance in growing the best crop and protecting natural resources.

Interested in Agronomy in the Field? Contact Angie Rieck-Hinz at amrieck@iastate.edu or 515-231-2830 to be placed on a contact list.

* Sawyer, John, Mallarino, Antonio, and Randy Killorn. 2004. Take a Good Soil Sample to Help Make Good Decisions. Iowa State University Extension PM 287. Link: https://crops.extension.iastate.edu/files/article/PM287.pdf

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Hanna Bates is the Program Assistant at the Iowa Water Center. She has a MS in Sociology and Sustainable Agriculture from Iowa State University. She is also an alumna of the University of Iowa for her undergraduate degree. 

Identifying Indicators for Soil Health

Breaking down our knowledge of soil enzymes

Post written by Marshall McDaniel, Assistant Professor in the Department of Agronomy at Iowa State University

As mentioned in a recent Washington Post article, there is a zoo beneath our feet in the soil. There are three properties of the soil, which are physical, chemical, and the biological properties. The emphasis on soil biology is, in large part, what separates soil health from the concepts of soil quality and the physical properties of soil (also known as soil tilth).  After all, only something that is living can be healthy (or unhealthy).  Many soil organisms are like us humans in that they require carbon as their main source of food in order to grow and reproduce.  Extracellular enzymes are proteins produced by microorganisms in soil to acquire carbon and nutrients from soil organic matter.

The McDaniel Lab was one of five to receive the Soil Health Literature and Information Review Grants from the Soil Health Institute. We will do a quantitative literature review on two of these enzymes – beta-glucosidase and polyphenol oxidase.  Beta-glucosidase can generally be thought of as being used for easily broken down, or labile, forms of soil carbon, and polyphenol oxidase for recalcitrant carbon.  In other words, think of labile carbon as a buffet of ‘yummy and healthy’ food that is nutritious and easy-to-digest for soil microbes, while recalcitrant carbon can be thought of as the equivalent of broccoli stems to human digestion.  We want to manage soils so that there is a large amount of the ‘yummy and healthy’ soil carbon for microbes to eat, and less of the ‘broccoli stems’.

Where the enzymes come in is that soil microbes will produce more of the beta-glucosidase enzyme if there is more ‘yummy and healthy’ forms of carbon in the soil, because it helps them to metabolize this form of carbon.  Conversely, if all you have left in the soil are ‘broccoli stems’, then as a soil microbe you are going to produce more polyphenol oxidase to metabolize this difficult to break down source of food.  Therefore, the ratio of these two enzymes holds promise as a good biological soil health indicator since it is an index of supply-and-demand for ‘yummy and healthy’ microbe food over ‘broccoli stems’.

What does this have to do with water?

Soil health and water quality go hand in hand. Improved soil health has the potential to increase water infiltration, increase water holding capacity, decrease surface runoff, decrease soil erosion, increase nutrient retention in the soil for plants, and more. By improving understanding of our soil biology, we can both better serve our natural resources and crop production.

Summer Update from the IWC Graduate Student Research Grant Program: Emily Martin

Emily Martin, MS in Environmental Science at Iowa State University, taking samples from a bioreactor
Nitrate batch test in the lab
Nitrate batch test in the lab
Nitrate batch test in the lab

Post submitted by Emily Martin, MS Environmental Science student at Iowa State University

Intensive farming and heavy nutrient application in the Midwest coupled with an extensive subsurface tile drainage network frequently leads to excessive nutrients in surface waters. As a result, heavy amounts of nitrogen and phosphorus has become a critical issue for policy and water research.

In spring 2017, I was awarded funding in the Iowa Water Center Graduate Student Supplemental Research Competition for my project titled, “Enhancing phosphate removal in woodchip bioreactors.” This project is conducted under advisement of Dr. Michelle Soupir at Iowa State University. A bioreactor is a subsurface trench along the edge of the field that can be filled with a range of different carbon sources. They are identified as a practice to help mitigate nutrient loss to flowing water systems, and so they deserve further research to understand their full capacity to capture water nutrients.

The goal of the project is to evaluate the ability of woodchip bioreactors to remove phosphorous by adding biochar as a phosphate (P) amendment to bioreactors. Objectives of the study are (1) to assess the effectiveness of different amendments on P removal in bioreactors and (2) to analyze the effect of influent P on overall removal.

We broke the project down into two main parts: a P sorption study and a column study. We completed part one during the month of June using 18 different types of biochar. The biochar was made by Bernardo Del Campo at ARTichar using three different temperatures of slow pyrolysis, 400°C, 600°C, and 800°C. We used six different types of biomass provided by the BioCentury Research Farm and the City of Ames, which are: switchgrass, corn stover, ash trees, red oak, mixed pine, and loblolly pine. The goal was to test a variety of biomass to see which would perform best as a P amendment and under which pyrolysis conditions they would function best.

Biochar is made using a process called pyrolysis. Pyrolysis is the burning of plant materials in a low to no oxygen chamber in order to “activate” the carbon structures that exists naturally within plants. The highly structured form of carbon rings in plants is desired for its stability and potential to adsorb or bind with chemicals, including phosphate and nitrate. There are two main types of pyrolysis: fast and slow, which refers to the amount of time the biomass remains in the pyrolysis chamber. Fast pyrolysis can be used to create biochar, but the yield is lower than slow pyrolysis. The temperature of pyrolysis can impact how the biochar interacts with different chemicals. In order to test these effects, we used three different temperatures when making our biochar.

Results from the P sorption study showed a few patterns. The main take away is that none of the biochars we tested adsorbed P exceptionally well; however, of the biochars we tested, the following were our top five P adsorbers:

  1. Corn stover @ 800°C
  2. Loblolly pine @ 600°C
  3. Red oak @ 600°C
  4. Switch grass @ 800°C
  5. Mixed pine @ 400°C

Because none of the biochars performed well in our P sorption test, we had to make a decision for the second part of the project. We came up with two options: (1) find new biomass and run the P sorption test again, or (2) test how well all 18 biochars remove nitrate from water. We chose option two and have begun nitrate batch tests, which will run throughout July. The batch tests are being run in one liter flasks and are tested at 4, 8, 12, and 24 hours to simulate woodchip bioreactor residence times found in the field.

After the nitrate batch test is complete, we will analyze results and decide if we will move forward with option one and see how other biomasses perform in a P sorption test.

Check back later on to learn more about the progress of this project!

 

A Day at the Lake

This week, our Iowa Water Center Advisory Board held their bi-annual meeting at the Iowa Lakeside Laboratory at Lake Okoboji in northwestern Iowa. At this meeting, we reviewed the activities of the Iowa Water Center as well as future projects. Staff members and the advisory board also visited the research field sites for Elizabeth Swanner, Assistant Professor in the Department of Geological and Atmospheric Sciences at Iowa State University. 

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Soil – Agriculture’s Reservoir

Post submitted by Hanna Bates, Program Assistant for the Iowa Water Center

The soil is like a sponge that holds water so it is available when crops need it. Wetter soil at the surface prevents deeper infiltration and so water is lost as surface runoff. Not only this, but soil moisture is also a variable that influences the timing and amount of precipitation in a given area. This is due to the impact it has on the water cycle. This cycle circulates moisture from the ground through evaporation and plant transpiration to the atmosphere and back to the ground again through precipitation. Therefore, the amount of water stored in the soil can affect the amount of precipitation received during the growing season.

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Satellite imaging from the European Space Agency. The center figure depicts imaging derived from SMOS.

According to Hornbuckle (2014), “we enter each growing season ‘blind’ as to whether or not there will be enough soil moisture and precipitation to support productive crops.” If there were a way to document and record water storage in the soil besides field measurements, we would have a better ability to predict future weather patterns and therefore, make better field decisions. Satellite remote sensing tools such as the European Space Agency’s Soil Moisture and Ocean Salinity (SMOS) and NASA’s Moisture Active Passive (SMAP) can be used to take such measurements. Before these tools can be used to estimate water storage and improve weather and climate predictions, researchers must compare them to what is actually measured within the soil. This process of confirming accuracy of a tool is called validation.

A project led by Dr. Brian Hornbuckle, and funded by the Iowa Water Center in 2014, sought to improve and validate SMOS and SMAP in near-surface soil moisture observations of Iowa. Hornbuckle used a network of soil moisture measurements located in the South Fork Watershed as a standard to validate the accuracy of SMOS and SMAP. At each site, soil moisture and precipitation was measured.

Some of the results of this research project are presented in a 2015 article published in the Journal of Hydrometeorology.  Rondinelli et al. found that SMOS and the network of soil moisture measurements detect different layers of the soil. SMOS takes measurements of the soil surface while the network observes a deeper level of soil. These results will allow scientists to better evaluate the accuracy of measurements from SMOS and SMAP and ultimately enhance our understanding of the water content of the soil surface.  As noted earlier, it is this layer of the soil that determines how much precipitation is lost to surface runoff.

In a subsequent study published in 2016, Hornbuckle et al. published further results that indicate new ways of using SMOS. Researchers found that SMOS can be used to look at water in vegetation, as opposed to water in the soil.  Hence SMOS might be used in the future to observe the growth and development of crops, and perhaps estimate yield and the time of harvest as opposed to conducting field surveys from the ground. It also has the potential to measure estimates of the biomass produced during the growing season, which could be useful to reach bioenergy production goals.

Research like this demonstrates that a single tool can be used in multiple ways to better understand our landscape. Not only this, but preliminary studies of SMOS also show that it is important to verify the accuracy of tools before relying on them. Like all research, the work is not done to identify all the potential uses for SMOS and SMAP.  A new NASA grant, in partnership with the Iowa Flood Center, will help get researchers even closer to making satellite measurements a useful, scientific tool to understand water near the soil surface.

References

Hornbuckle, Brian K. “New Satellites for Soil Moisture: Good for Iowans!.” A Letter from the Soil & Water Conservation Club President (2014): 20.

Hornbuckle, Brian K. Jason C. Patton, Andy VanLoocke, Andrew E. Suyker, Matthew C. Roby, Victoria A. Walker, Eswar R Iyer, Daryl E. Herzmann, and Erik A. Endacott. 2016. SMOS optical thickness changes in response to the growth and development of crops, crop management, and weather. Remote Sensing Environment (180) 320-333.

Rondinelli, Wesley J., Brian K. Hornbuckle, Jason C. Patton, Michael H. Cosh, Victoria A. Walker, Benjamin D. Carr, Sally D. Logsdon. 2015. Different Rates of Soil Drying after Rainfall Are Observed by the SMOS Satellite and the South Fork in situ Soil Moisture Network. Journal of Hydrometeorology. April 2015.

 

View from my Windshield: Observations of soil erosion across Iowa

For the past couple of weeks, I have been on the road across Iowa. These trips vary in their purpose, but one thing that remains the same is the evident erosion in the fields along my travels. Regardless of where I am – whether it is in the Loess Hills visiting family or in the Des Moines Lobe for a meeting – spring rains have revealed that there are deep cuts in the bare brown soils where lush, even soils used to be.

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