Environmental Biophysics

Aug 22

Do Soil Microbes Influence Plant Response to Heat Waves? (Part II)

Rachel Rubin, PhD candidate at Northern Arizona University and her team at Northern Arizona University are investigating the role soil microbes play in plant response to heat waves, including associated impacts to microbial-available and plant-available water (see part 1). Because heat waves threaten plant productivity, they present a growing challenge for agriculture, rangeland management, and restoration. Below are the results of Rachel’s experiments, some of the challenges the team faced, and the future of this research.

Heat waves present a growing challenge for agriculture, rangeland management, and restoration.

Challenges

Rachel says the experiment was not without its difficulties. After devoting weeks towards custom wiring the electrical array, the team had to splice heat-resistant romex wire leading from the lamps to the dimmer switches, because the wires inside the lamp fixtures kept melting. Also, automation was not possible with this system. She explains, “We were out there multiple times a day, checking the treatment, making sure the lamps were still on, and repairing lamps with our multi-tools. We used an infrared camera and an infrared thermometer in the field, so we could constantly see how the heating footprint was being applied to keep it consistent across all the plots.”

Arizona Fescue (image: wickipedia.com)

Some Grass was Heat Resistant

Rachel says her biggest finding was that all of the C4 grasses survived the field heat wave, whereas only a third of the Arizona Fescue plants survived. She adds that the initially strong inoculum effects in the greenhouse diminished after outplanting, with no differences between intact, heat-primed inoculum or sterilized inoculum for either plant species in the field. “It may be related to inoculum fatigue,” she explains, “the microbes in the intact treatment may have become exhausted by the time the plants were placed in the field, or maybe they became replaced, consumed, or outcompeted by other microbes within the field site”. Rachel emphasizes that it’s important to conduct more field experiments on plant-microbe interactions. She says, “Field experiments can be more difficult than greenhouse studies, because less is under our control, but we need to embrace this complexity. In practice, inoculants will have to contend with whatever is already present in the field. It’s an exciting time to be in microbial ecology because we are just starting to address how microbes influence each other in real soil communities.”

Grass going to seed in an open-air field

Diminished effects may be related to inoculum fatigue.

What’s In Store?

Now that the team has collected data from the greenhouse and from the heat wave itself, they have started looking at mycorrhizal colonization of plant roots, as well as sequencing of bacterial and archaeal communities from the greenhouse study. Rachel says, “It’s quite an endeavor to link ‘ruler science’ plant restoration to bacterial communities at the cellular level. I’m curious to see if heat waves simply reduce all taxa equally or if there is a re-sorting of the community, favoring genera or species that are really good at handling harsh conditions.”

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Aug 15

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Do Soil Microbes Influence Plant Response to Heat Waves?

Rachel Rubin, PhD candidate at Northern Arizona University, is interested in the intersection of extreme climate events and disturbance, which together have a much greater impact on plant communities. She and her team at Northern Arizona University are investigating the role soil microbes play in plant response to heat waves, including associated impacts to microbial-available and plant-available water.

Plants have a tight co-evolutionary history with soil microbes. It has been said that there is no microbe-free plant on earth.

Because heat waves threaten plant productivity, they present a growing challenge for agriculture, rangeland management, and restoration.

Can Soil Microbes Increase Heat Resistance?

Many plants maintain mutualistic associations with a diverse microbiome found within the rhizosphere, the region of soil that directly surrounds plant roots. These “plant growth-promoting rhizobacteria” and arbuscular mycorrhizal fungi provision limiting resources including water, phosphorus and nitrogen in exchange for photosynthetically derived sugars. However, we understand very little about whether extreme events can disrupt these interactions.

Fig. 1. Fine roots exploring the inoculum that was added as a band between layers of potting mixture.

Rachel and her team exposed rhizosphere communities to heat stress and evaluated the performance of native grasses both in the greenhouse, and transplanted under an artificial heat wave. They hypothesized that locally-sourced inoculum (a sample of local soil containing the right microbes) or even heat-primed inoculum would help alleviate water stress and improve survival of native grasses.

The Experiments

Rubin started in the greenhouse by planting Blue Grama (Bouteloua gracilis, C4 grass) and Arizona Fescue (Festuca arizonica, C3 grass) and assessed their responsiveness to locally collected soil inoculum that had either been left intact, pre-heated or sterilized (Fig. 1). Rubin says, “We expected that our plants would benefit the most from having intact soil microbe communities. But, we were surprised to find very large differences between plant species. Blue Grama performed the best with intact inoculum, whereas Arizona Fescue performed better with pre-heated or sterilized soil”. This could mean that Blue Grama is more dependent on its microbiome, whereas Arizona Fescue engineers a rhizosphere that contains more parasitic microbes rather than mutualistic microbes. Rachel says that understanding this relationship is important for tailoring plant restoration projects to local conditions. Plants that exhibit high levels of mutualisms with their rhizosphere might require an extra inoculum “boost” in order to successfully establish in highly degraded soil, whereas we should not bother to inoculate plants that tend to harbor parasites within their rhizosphere.

Research plot using infrared sensors and METER soil water content and soil water potential sensors

Fig. 2. A heated plot in the foreground connected to infrared lamps, water content and matric potential sensors, and EM50 data loggers.

After the team studied these responses, they planted the grasses into a degraded section of a grassland and installed an array of 1000-Watt ceramic infrared lamps mounted on steel frames (Fig. 2) to address whether inoculation influenced plant performance and survival. With help from a savvy undergraduate electrical engineering major (Rebecca Valencia), Rubin simulated a two-week heat wave while monitoring soil temperature and moisture using water content and water potential sensors. She also measured plant performance (height, leaf number and chlorophyll content) before, during, and after the event. Control plots had aluminum “dummy lamps” to account for shading.

An infrared photo, which is how Rachel determined that the heating footprint was evenly distributed on all the plants. The scale bar on the right is in degrees C.

Data obtained from soil sensors helped Rachel to measure heating treatment effects as well as rule out a potential cause for plant mortality: soil moisture. “Soil temperature was on average 10 degrees hotter in heated plots than control plots, but matric potential and soil water content were completely unaffected by heating. This tells us that the grasses died from reasons other than water stress– perhaps a top-kill effect.” Although growing concern over heat waves in agriculture is centered around accompanying droughts, this experiment demonstrates that heating can produce negative effects on some species even when water is in plentiful supply.

Next week: Learn the results of Rachel’s experiments, some of the challenges the team faced, and the future of this research.

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Aug 8

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A New Method for Preventing Snow Mold In Winter Wheat (Part 2)

When faced with a reluctant spring thaw, dryland wheat growers know they have only two weeks to remove the snow from their fields, or large sections of their crop will die off from snow mold. Melting the snow artificially can be an expensive process, but one southern Idaho wheat grower has found a unique solution that could save both money and the environment (see part 1). He covers the snow with displaced topsoil, which speeds up the warming process and is less expensive than using traditional fly ash. This week, find out which techniques Campbell uses to save time and money while redistributing his soil.

A snow dusted field with a partly cloudy sky and a bright sunset

Campbell says the number of passes he has to make with his tractor makes a difference.

Soil Application

Campbell says the number of passes he has to make with his tractor makes a difference, so he spreads the soil in patches, rather than evenly, in order to save time and money. “What we’ve found is, if you can get the soil deposited every 40 feet (9 m), you start changing the temperature in the whole area, and not just where the soil was dropped. The breeze will spread the warmth, and the snow in between the patches of soil will melt a lot faster. We do adjust our spacing depending on the amount of snow. If there’s more snow, that means we’ve got less time, and it’s got to melt faster, so we’ll place the patches of soil closer together for more even coverage.

Tractor sitting in a field with a researcher standing in front of it

Using a tractor to spread the soil in patches, rather than evenly, saves time and money.

Campbell adds that he is selective on which field he spreads the soil. If the weather conditions are not looking good, and they have deep snow, then they may skip a field they think they can’t save. Or if the fields further south have less snow, and the weather looks warm, they may also skip that field because the snow may melt on it’s own. There are challenges in trying to make those predictions, however. He says, “It’s hard to make those guesses based on the weather forecast because the predictions just aren’t very accurate a couple of weeks out. One year the forecast was sunny, so we applied fly ash to the fields. But the next day it snowed a foot, and it was two weeks before that snow melted so the sun could get to the ash. We lost quite a bit of grain that year.”

Campbell is selective on which field he spreads the soil.

Future Plans

Next year Campbell will try mixing the soil with some fly ash, to take advantage of the ash’s darker color. He says, “We’re going to keep putting the soil back on the field. It’s less expensive, and we don’t have to haul it. Next year we’ll try mixing the soil with about ⅓ ash so we can get it a little blacker. It will be a nice middle ground where the dark color will melt the snow, yet it won’t cost too much. And we can redistribute the eroded, nutrient-rich topsoil.”

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Aug 1

A New Method for Preventing Snow Mold In Winter Wheat

Each year in early spring, dryland wheat farmers battle for their crop’s survival. As temperatures climb to 0 degrees C, the dark, wet microclimate underneath the snow begins to propagate snow mold.

Wheat spikes in a wheat field.

Soil scientist, Dr. Colin Campbell says, “Soil under a blanket of snow can warm as spring temperatures rise, despite their icy covering. Temperatures above freezing and the water from snowmelt are a perfect environment for mold to grow.“

When faced with these weather conditions, wheat growers know they have only a couple of weeks to remove the snow, or large sections of their crop will die off. Melting the snow artificially can be an expensive process, but one southern Idaho wheat grower has found a unique solution that could save both money and the environment.

Temperatures above freezing and the water from snowmelt are a perfect environment for mold to grow.

The Old Method

Traditionally, wheat growers have spread fly ash (ash from coal) on the spring snow to try and speed the melting process. The black fly ash creates a warmer microclimate by absorbing more solar radiation rather than reflecting it. To demonstrate its effectiveness, the USDA performed studies using fly ash to speed snow melt, with positive results. However, growers say the challenge is using the method in a way that is economical on dryland wheat where the profit margin is narrow. Bryce Campbell, a dryland wheat farmer near Burley, ID, says, “Some people use fly ash to get in the field faster or to get the water flowing into the soil, but our primary goal is to prevent snow mold from killing the winter wheat. If that happens, we have to replant the crop to a spring crop which yields a lot less. Our goal is to try and keep our crop alive.”

Field with loose top soil and extensive edging

During heavy rain events, topsoil washed down to the edges of the field, collecting in dikes Campbell constructed.

An Inexpensive New Method

Campbell has used fly ash in the past, but last year, he had a better idea. He noticed that during heavy rain events, some of his topsoil washed down to the edges of the field, collecting in dikes he constructed and eventually becoming dried and powdery. He wondered if he could use that soil as an economical replacement for fly ash. In the fall, he collected some in a truck and left it to dry completely in the back of his shed; then this season, he spread it over the spring snow. Seeing the results, he decided it was worth the effort, both economically and environmentally. Campbell estimated the fly ash melt to be approximately 30% faster than the powdered soil because of its darker color, but the soil was free, which made a difference in his bottom line.

If snow mold kills the wheat crop, growers have to replant the crop to a spring crop which yields less.

He adds, “Some of the wheat farmers down the road are using a finely ground coal dust product to melt their snow. It’s a great product, and it works really well for melting snow, but their cost is about $20/acre. When you spread that on a thousand acres, that’s $20,000. I can put my soil on a thousand acres, and my only cost is two hours of gathering up the soil plus a day and a half in the tractor for application.”

Next week: Find out which techniques Campbell uses to save time and money redistributing his displaced soil.

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Jul 25

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Which Factors Make Rain Gardens More Effective? (Part 2)

Scientists often evaluate Low Impact Development (LID) design by quantifying how much stormwater rain garden systems (cells) can divert from the sewer system. But Dr. Amanda Cording and her research team want to understand what’s happening inside the cell in order to improve the effectiveness of rain garden design (see part 1). Below are the results of their research.

Deep rooted systems were found to have a much better ability to hold the soil in place and remove nutrients.

Key Findings

Cording says that some of her key findings were that the soil media and vegetation selection is absolutely crucial to the performance of these systems. Cording’s team looked at the root layering perspective in three dimensions and found that deep rooted systems were found to have a much better ability to hold the soil in place and remove nutrients throughout the life cycle of the cell. The more surface area the roots covered, the more pollutants the cell would remove. She adds, “Cells with deep-rooted plants were found to be resilient during increased precipitation due to climate change, did well at retaining peak flow rates, and performed well at removing total suspended solids and nutrients predominantly associated with particulates.” Labile nutrients, Cording says, were a completely different story. She says the bioretention systems have to be specifically designed to remove those nutrients through sorption (P) and denitrification (N).

Compost was found to have a negative effect on water quality.

Compost, which is often used as an organic amendment in the soil media to help remove heavy metals and provide nutrients for the plants, was found to have a negative effect on water quality overall, due to the high pre-existing labile N and P content. She says, “It’s intuitive, but at the same time, a lot of these systems are designed based on bloom time and color, and not necessarily on the physical and chemical pollutant removal mechanisms at work.”

Green algal bloom in a small freshwater lake in New Zealand. (Image: Massey University)

What Lies Ahead?

Cording also tested a proprietary bioengineered media in two of her cells which was designed to remove the phosphorous that causes algal blooms in the rivers and streams. She says, “It did a phenomenal job. There was very little phosphorous coming out compared to the traditionally-designed retention cells. Cording, who is now based in Honolulu and works for an ecological engineering company called EcoSolutions, is looking at how to use natural, highly-leached iron rich soils, to get a similar amount of phosphorous removal, and how bioretention can be designed with anoxic storage zones to remove nitrate via denitrification. She says, “These nutrients can be easily removed from stormwater with a little conscious design effort and a splash of chemistry.”

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Jul 15

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Which Factors Make Rain Gardens More Effective?

Low Impact Development (LID) is an approach to development (or re-development) that mimics pre-development hydrology and uses ecological engineering to remove pollutants in stormwater and wastewater so it can be reused or replenish groundwater supplies. Examples of LID features include porous pavement, constructed wetlands, green roofs, and rain gardens. LID stormwater bioretention systems such as rain gardens have been proven to work, but are they designed as effectively as they could be? Dr. Amanda Cording (formerly at the University of Vermont) and her team wanted to understand which design factors would make rain gardens more resilient, increase phosphorus adsorption, and reduce nitrates.

Cording and her team wanted to understand what was happening inside bioretention cells.

What’s Happening Inside?

Scientists often evaluate LID design by quantifying how much stormwater the systems (cells) can divert from the sewer system. But Cording and her team wanted to understand what was happening inside the cell. They wondered which types of soil media and infrastructure would optimize a stormwater bioretention system’s ability to improve water quality. She says, “We wanted to gather water quality information coming in and going out of the system. I designed inflow and outflow monitoring infrastructure to measure nutrient and sediment pollution.” The system monitored pollution by sampling stormwater runoff from a paved road surface before and after it went through bioretention cells. Each cell was constructed with different features to test the influence of vegetation and soil media on pollutant removal capabilities.

Bioretention cells at the newly constructed Bioretention Laboratory at the University of Vermont.

Methods Used

To understand what was happening within eight bioretention cells at the newly constructed Bioretention Laboratory at the University of Vermont, Dr. Cording and her team investigated the mechanisms influencing greenhouse gas emissions and nutrient transformations at various depths in engineered soil media. In addition to using her own monitoring infrastructure, Dr. Cording used soil moisture sensors to measure water content within the soil media. She says, “I was comparing different vegetation treatments while simulating increased precipitation due to climate change in the Northeast. I put the soil probes in at 5 cm and 61cm, one on top of the other. Then I looked at the way the EC and the volumetric water content (VWC) changed prior to a storm event, during a storm event, and after a storm event.”

One of the team’s bioretention cells at the University of Vermont.

Cording says the EC and VWC sensors allowed them to get a general sense of what was happening inside the cell over time. She adds, “I used the data when I needed to know more of the story, such as how the conductivity at the surface compared to other depths so we could see if the nutrients in the soil were migrating, and how much was moving down. We were also able to use the sensors to compare the VWC around the roots of different vegetation types. It provided a lot of insight into the dynamic world that exists below the soil surface.”

Next Week: Read about the team’s key findings and what lies ahead for this research.

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Jul 8

Improving Drought Tolerance in Soybean

Limited water availability is a significant issue threatening the agricultural productivity of soybean, reducing yields by as much as 40 percent. Due to climate change, varieties with improved drought tolerance are needed, but phenotyping drought tolerance in the field is challenging, mainly because field drought conditions are unpredictable both spatially and temporally. This has led to the genetic mechanisms governing drought tolerance traits to be poorly understood. Researcher Clinton Steketee at the University of Georgia is trying to improve soybean drought tolerance by using improved screening techniques for drought tolerance traits, identifying new drought tolerant soybean germplasm, and clarifying which genomic regions are responsible for traits that help soybeans cope with water deficit.

Researchers are trying to improve soybean drought tolerance by using better screening techniques for drought tolerance traits.

Which Traits Are Important?

Clinton and his colleagues are evaluating a genetically diverse panel of 211 soybean lines in two different states, Kansas and Georgia, for over two years to help him accomplish his research objectives. These 211 lines come from 30 countries and were selected from geographical areas with low annual precipitation and newly developed soybean lines with enhanced drought-related traits, along with drought susceptible checks. The researchers are looking at traits such as canopy wilting. Some plants will take a few days longer to wilt, allowing these plants to continue their photosynthetic ability to produce biomass for seed production. Other traits that he is interested in evaluating are stomatal conductance, canopy temperature with thermal imaging, relative water content, and carbon isotope discrimination.

The scientists want to monitor traits such as canopy wilting.

Use of Microclimate Stations to Monitor Environmental Conditions

Clinton says to make selection of drought-tolerant lines easier and more predictable, knowledge of field environmental conditions is critical. He says, “You can phenotype all you want, but you need the true phenotype of the plant to be observed under real drought conditions so you can discover the genes for drought tolerance and improve resistance down the line in a breeding program.”

In addition to soil moisture sensors, the team used microclimate weather stations to help monitor water inputs at their two field research sites and determine ideal time periods for phenotyping drought-related traits. Steketee says, “We put microenvironment monitors in the field next to where we were growing our experimental materials. Both locations use those monitors to keep an eye on weather conditions throughout the growing season, measuring temperature, humidity, and precipitation. Since we could access the data remotely, we used that information to help us determine when it was time to go out to the field and look at the plots. We wanted to see big differences between soybean plants if possible, especially in drought conditions. By monitoring the conditions we could just go back to our weather data to show we didn’t get rain for 3 weeks before we took this measurement, proving that we were actually experiencing drought conditions.”

The team identified some lines that performed well.

Results So Far

Though 2015 wasn’t a great year for drought in Georgia, Clinton says there was a period in late July when he was able to measure canopy wilting, and they identified some lines that performed well. He says, “We compared our data to the data collected by our collaborator in Kansas, and there are a few lines that did well in both locations. Hopefully, another year of data will confirm that these plants have advantageous drought tolerance traits, and we’ll be able to probe the advantageous traits out of those lines and integrate them into our breeding program.”

Future Plans

The team will use what’s called a genome-wide association study approach to identify genomic regions responsible for drought tolerance traits of interest. This approach uses phenotypic information collected from the field experiments along with DNA markers throughout the soybean genome to see if that marker is associated with the trait they are interested in. If the scientists find the spot in the genome that is associated with the desired trait, they will then develop genomic tools to be used for selection, integrate that trait into elite germplasm, and ultimately improve the drought tolerance of soybeans.

See weather sensor performance data for the ATMOS 41 weather station.

Explore which weather station is right for you.

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Jun 30

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Crowdsource Your Data Collection?

What can you do when you need data from all over the world in a short amount of time? Many scientists, including ones at JPL/NASA, are crowdsourcing their data collection.

Projects range from ground truthing NASA satellite data, to spotting migration patterns, to collecting microbes.

Darlene Cavalier, Professor of Practice at Arizona State University is the founder of SciStarter, a website where scientists make data collection requests to a community of volunteers who are interested in collecting and analyzing data for scientific research.

Who Collects the Data?

SciStarter was an outgrowth of Cavalier’s University of Pennsylvania graduate school project where she sought to connect people who didn’t have formal science degrees with scientists who needed their help. She says, “We know from various National Science Foundation reports that many people without science degrees are interested in participating in and learning about science. The challenge was that there was no easy way to find those opportunities.”

One project invites UK citizens to find and take pictures of orchids.

Cavalier started SciStarter, in part, to create a “one-stop shop” resource where people could easily search and find projects best suited to their locations and interests. She says, “We have over 1,600 projects and events. Projects range from ground truthing NASA satellite data, to spotting migration patterns, to collecting microbes.” One project, sponsored by the National History Museum in London, invites UK citizens to find and take pictures of orchids with their smartphones, so scientists can study the effect of climate change on UK flowering times.

How Are Volunteers Recruited?

Volunteers are recruited through SciStarter’s partnerships with the National Science Teachers Association, Discover Magazine, the United Nations, PBS and more. One of the most visible ways that volunteers are enlisted is through an organization Cavalier started called Science Cheerleader. The organization consists of 300 current and former NFL and NBA cheerleaders who are scientists and engineers. These role models visit youth sports groups, go to science festivals, and talk in schools. During their appearances they engage people of all ages in actual citizen science projects. Darlene says, “This is our way of casting a wide net and making new audiences aware of these opportunities.”

Science cheerleader consists of 300 current and former NFL and NBA cheerleaders who are now scientists and engineers.

What’s the Ultimate Goal?

Cavalier is determined to create pathways between citizen science and citizen science policy. She says, “The hope is after people engage in citizen science projects, they will want to participate in deliberations around related science policy. Or perhaps policy decision makers will want to be part of the discovery process by contributing or analyzing scientific data.” Darlene has partnered with Arizona State University and other organizers to form a very active network called Expert and Citizen Assessment of Science and Technology (ECAST). This group seeks to unite citizens, scientific experts, and government decision makers in discussions evaluating science policy. Cavaliers says, “The process allows us to discover ethical and societal issues that may not come up if there were only scientists and policy makers in a room. It’s a network which allows us to take these conversations out of Washington D.C. The conversations may originate and ultimately circle back there, but the actual public deliberations are held across the country, so we get a cross-section of input from different Americans.” ECAST has been contracted by NASA, NOAA, the Department of Energy, and others to explore specific policy questions that would benefit from the public’s input.

ECAST is a network which allows us to take science policy conversations out of Washington D.C.

Overcoming Obstacles

Cavalier says the SciStarter team constantly works to remove challenges and impediments to public participation. She explains, “We’ve found it can be difficult to articulate the geographic bounds of a project because when a researcher says, “this project can be done in a watershed,” it doesn’t mean anything to most people. So SciStarter spent time developing a system of “Open Streetmap and USGS databases that show land-type coverage.”

Another obstacle to some types of research is access to instrumentation. Darlene comments, “The NASA Soil Moisture Active Passive (SMAP) project really opened our eyes to how many obstacles can exist between the spectrum of recruiting, training, equipping, and fully engaging a participant.” This year, SciStarter is building a database of citizen science tools and instruments and will begin to create the digital infrastructure to map tools to people and projects through a “Build, Borrow, Buy” function on project pages.

Image of the world from a satellite view

“The NASA Soil Moisture Active Passive (SMAP) project really opened our eyes to how many obstacles can exist to full engagement.”

What’s Next?

Darlene says that sometimes scientists who want accurate data without knowing about or identifying a particular sensor for participants to use often create room for data errors. To address this problem, SciStarter and Arizona State University will be hosting a summit this fall where scientists, citizen scientists, and commercial developers of instrumentation will meet to determine if it’s possible to fill gaps to develop and scale access to inexpensive, modular instruments that could be used in different types of research. You can learn more about crowdsourcing your data collection with SciStarter here.

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Jun 24

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Lysimeters Determine If Human Waste Composting Can Be More Efficient (Part 2)

In Haiti, untreated human waste contaminating urban areas and water sources has led to widespread waterborne illness.

Hospital rooms in Haiti with patients infected with cholera

Waterborne disease is the leading cause of death for children under 5. Currently, Haiti is battling the largest cholera outbreak in recent history. Over 1/6 of the population is sickened to date.

Sustainable Organic Integrated Livelihoods (SOIL) has been working to turn human waste into a resource for nutrient management by turning solid waste into compost. (See part 1).

Water ways infected with waste and trash

Contaminants making their way into the waterways.

The organization plans on performing experiments with lysimeters, to determine if human waste will contaminate Haitian soil during the composting process.

A river infected with waste right below a huge forest

Even in places where there are toilets, they are often poorly designed or poorly placed. This latrine is located just above a river, where people are getting their bathing and drinking water.

Lysimeters Help Assess Health Hazards

SOIL will use G3 passive capillary lysimeters in an experiment to determine if composting human waste without a barrier between the waste and the soil will result in ecological and/or health hazards. Why? The problem is “jikaka,” or “poo juice.” The compost facility currently redistributes it onto the compost and finishing piles, but they would rather not have to manage it. They believe if they remove the concrete slab and allow composting to occur in contact with soil, the composting process will be easier and faster.

SOIL’s agricultural team conducts studies on the use of compost to improve farming practices and maximize economic benefits of targeted compost application.

The Experiment

The organization will test their idea as they expand their facility. New compost bins and staging areas for finishing have been built absent concrete pads. G3 passive capillary lysimeters have been installed, three beneath the compost bin, and four beneath the first staging area for finishing. They will be used to monitor the amount of moisture (jikaka) that travels through the soil as well as check for anything harmful that travels with it.

SOIL’s human waste compost was found to increase sorghum yields by 400%.

What’s the Future for Konpòs Lakay?

SOIL’s agricultural team studies the use of their compost (Konpòs Lakay) in order to optimize farming practices and the economic benefits of targeted compost application. The data they collect will help them expand the market for Konpòs Lakay, which in turn will support the sustainability of SOIL’s sanitation programs.

For more information on SOIL’s waste treatment efforts, visit their website, or watch the video below, a TEDx talk given by SOIL co-founder, Sasha Kramer.

Discover G3 Drain Gauge passive capillary lysimeters→

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Jun 17

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Lysimeters Determine If Human Waste Composting Can Be More Efficient

In Haiti, untreated human waste contaminating urban areas and water sources has led to widespread waterborne illnesses such as typhoid, cholera, and chronic diarrhea.

Human wastes are making their way into Haiti’s waterways.

Sustainable Organic Integrated Livelihoods (SOIL) has been working since 2006 to shift human waste as a threat to public health and source of pollution to being a resource for nutrient management by turning solid waste into compost. This effort has been critical to sustainable agriculture and reforestation efforts, as topsoil in Haiti has severely eroded over time, contributing to Haiti’s extreme poverty and malnutrition.

Border between Haiti and the Dominican Republic from an aerial view

This is a very famous image of the border between Haiti and the Dominican Republic. It’s often used to demonstrate how badly off Haiti is relative to their neighbors. What you’re actually seeing is the environmental scars of a very different post-colonial history.

Why Compost?

Topsoil erosion in Haiti was estimated to be 36.6 million metric tons annually in 1990, and it is estimated that only one sixth of the land currently cultivated in Haiti is suitable for agriculture. SOIL combats desertification by producing over 100,000 gallons of agricultural-grade compost made from human waste annually. SOIL research has shown that this compost can increase crop yields by up to 400%. The organization has sold over 60,000 gallons of this compost to local farmers and organizations, increasing soil organic matter and nutrients throughout the country.

Waste covers the urban area infecting people and causing problems

Today in Haiti, only 25% of people have access to a toilet – meaning people are forced to go to the bathroom outside or in urban areas, in a plastic bag, which often times gets disposed of in a canal or an empty lot.

How Do They Do It?

SOIL distributes specially constructed toilets throughout Haiti that separate urine from solid waste. Odors are reduced by covering the solid waste with organic cover material. The toilet utilizes a five gallon bucket to collect solid waste that can be swapped out when full.

Instead of flushing nutrients away with fresh water, people use a dry carbon material to cover it up so that it doesn’t smell, and it doesn’t attract flies. This material also provides food for the microbes that will ultimately transform the poop.

The five gallon buckets are collected weekly and taken to the composting facility, where they are dumped into large composting bins. It takes about 1500 buckets (3-4 days worth) to fill each bin. Bins are required to reach 122°F and left for 2.5 months in order to kill all pathogens.

Wastes are safely transformed into nutrient-rich compost in a carefully monitored composting treatment process that exceeds the World Heath Organization’s standards for the safe treatment of human waste.

The compost is then removed from the bin and turned by hand. There are three concrete slabs used to manage the finishing process. Compost is turned horizontally and then moved forward to the next slab, allowing multiple batches to be finishing at the same time, each at a different stage. After processing, the compost is sifted, bagged, and sold, reinvigorating the agriculturally-based Haitian economy.

Students study plants sold for agriculture

The compost SOIL produces is bagged under the Haitian Creole brand name “Konpòs Lakay” and then sold for agricultural application, improving both the fertility and water retention of soil. With over four billion people worldwide currently lacking access to waste treatment services, finding ways to provide waste treatment services profitability through the private sector has the potential to dramatically improve public health and agricultural outputs globally.

Continue reading part 2→

Understand the Impact

Watch this 5 minute video filmed by independent parties to see how SOIL is impacting Haitian citizens and the environment.

Read how experiments using lysimeters will help SOIL make the composting process more efficient.

Download the “Researcher’s complete guide to soil moisture”—>

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Measuring and Modeling the Environment

Challenges

Some Grass was Heat Resistant

What’s In Store?

Can Soil Microbes Increase Heat Resistance?

The Experiments

Soil Application

Future Plans

The Old Method

An Inexpensive New Method

Key Findings

What Lies Ahead?

What’s Happening Inside?

Methods Used

Which Traits Are Important?

Use of Microclimate Stations to Monitor Environmental Conditions

Results So Far

Future Plans

Who Collects the Data?

How Are Volunteers Recruited?

What’s the Ultimate Goal?

Overcoming Obstacles

What’s Next?

Lysimeters Help Assess Health Hazards

The Experiment

What’s the Future for Konpòs Lakay?

Why Compost?

How Do They Do It?

Understand the Impact