Posts from the ‘Canopy’ Category

Nov 14

Sensor Data Improves Cherry Production

In July of 2013, Lav Khot and his team were in the field looking at how cherries were picked, weighed, and transported, when suddenly a helicopter began circling around a nearby orchard block. When Dr. Khot asked the grower about it he said, “There was a rain last night, and we are trying to dry the tree canopies.” The grower told Khot that cherries are susceptible to cracking if moisture stays on the fruit too long, so they hire helicopters to fly over their orchards to remove water from the fruit and leaves, hoping to prevent fruit loss.

The economic impact of solving the cherry cracking problem could be huge as growers now suffer heavy losses each year.

Fresh market cherries are a lucrative business. That’s how the growers can afford the approximately $25K it costs to rent the helicopters every season. They try to do everything that they can to stop any cracking or splitting, but interestingly, Dr. Khot says grower decisions are influenced completely by emotion. “If there is a rain event, the farmer will become anxious, and they will hire pilots to fly the helicopter.”

Dr. Khot wondered if he could help the cherry growers make their decisions based on real data instead. He and his postdoc, Dr. Jianfeng Zhou, are using leaf wetness sensors to determine if and how long water is present on the tree canopies after a rain event. Dr. Khot hopes that the data from these sensors will help growers decide whether or not it makes sense to fly the helicopter.

Why the cherries split

Not all varieties of cherry crack, but high sugar content varieties do as the skin is thin during maturation. There are two hypotheses associated with fruit splitting or cracking:

Irrigation: High water availability in the soil as the fruit is maturing (a few weeks before harvest) encourages trees to take up more water and causing the fruit to split.

Rainwater: Rain collects in the cherry stem bowl or hangs off the bottom and is slowly absorbed into the fruit along the osmotic potential gradient. The fruit will start to split due to increased pressure inside the skin.

Dr. Khot and his team will use soil moisture sensors to investigate the first hypothesis with the object of improving irrigation management, especially as harvest approaches. And he’s getting some support: “Dr. Matt Whiting (colleague at the Center for Precision and Automated Agricultural Systems, Washington State University) is helping us understand this cracking phenomenon from the soil perspective. He is doing work on deficit irrigation (reducing the rate of irrigation below optimal) towards harvest time and seeing how that relates to cracking. Also, the WSU CAHNRS ERI (Emerging Research Issues grant), which supports high-risk research, has funded us $75,000, along with Decagon who is supporting us with their sensors.”

Last Year’s Research

There are two approaches to drying canopies. One uses a sprayer that produces a cross-wind that moves sideways through the canopies, while the other uses the downwash from helicopter blades. Last year, Dr. Khot and his research assistant experimented with crosswind velocities to see how much wind was being generated and how much water was really being dispersed. Dr. Khot commented, “Last season we went out to the WSU orchard and ran the sprayer at two settings in order to see how water was removed and how much wind was coming through the canopies for a given amount of time.” They had good success at both removing the water from the trees and measuring it with the leaf wetness sensors. But, they started the measurements after the cherries had matured, so weren’t able to tie it to cracking.

This Year’s Experiment

One issue with using helicopters is that they are extremely dangerous. Accidents are not uncommon, and unfortunately pilots have died. This year the team will also evaluate the efficacy of a mid-size, unmanned helicopter in order to test if it can produce enough downwash to dry the cherries and compare it with manned helicopters. Dr. Khot says, “The helicopters are large and difficult to fly close to the canopies, but we can program the unmanned drone to fly close to the canopy and get rid of the water safely.” Digital Harvest and Yamaha, who are supporting this aspect of the research, have received an exemption from the FAA so they can test their unmanned helicopter.

Differing Tree Architectures

Dr. Khot’s team did their first experiments on traditional cherry tree architectures (imagine a typical tree), but this year they will perform their experiments on trees that are trained into a “Y” shape, or completely vertical.

These trees represent traditional tree architecture, but this year researchers will perform their experiments on trees that are trained into a “Y” shape, or completely vertical.

Researchers have developed these new architectures for ease of harvesting and management, but Dr. Zhou says that there will be less canopy variability and thus more interpretable results compared to the traditional tree architecture where wind velocity is more heterogeneous throughout the canopy.

Economic Impact

Dr. Khot says the economic impact of solving the cherry cracking problem could be huge as growers now suffer heavy losses each year. One former grower underscored this when he noted they lost one crop in every four. But, there could be other benefits as well. The implications of this research could lead to solving other grower problems such as disease and pest management. “WSU already has a good AgWeatherNet program where we monitor the weather outside the trees at different locations, but not inside the canopies. If we had some smart sensing equipment like the leaf wetness sensor sitting in the canopy monitoring the wetness level over a 24-hour cycle, then we could develop some models based on the wetness and relate them to the number of pests at different locations in the orchard. That is something every grower can benefit from.”

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Nov 9

Screening for Drought Tolerance

Screening for drought tolerance in wheat species is harder than it seems. Many greenhouse drought screenings suffer from confounding issues such as soil type and the resulting soil moisture content, bulk density, and genetic differences for traits like root mass, rooting depth, and plant size. In addition, because it’s so hard to isolate drought stress, some scientists think finding a repeatable screening method is next to impossible. However, a recent pilot study done by researcher Andrew Green may prove them wrong.

Automatic Irrigation Setup

The Quest for Repeatability

Green says, “There have been attempts before of intensively studying drought stress, but it’s hard to isolate drought stress from heat, diseases, and other things.” Green and his advisors, Dr. Gerard Kluitenberg and Dr. Allan Fritz, think monitoring water potential in the soil is the only quantifiable way to impose a consistent and repeatable treatment. With the development of a soil-moisture retention curve for a homogeneous growth media, they feel the moisture treatment could be maintained in order to isolate drought stress. Green says, “Our goal is to develop a repeatable screening system that will allow us to be confident that what we’re seeing is an actual drought response before the work of integrating those genes takes place, since that’s a very long and tedious process.”

Why Hasn’t This Been Done Before?

Andrew Green, as a plant breeder, thinks the problem lies in the fact that most geneticists aren’t soil scientists. He says, “In past experiments, the most sophisticated drought screening was to grow the plants up to a certain point, stop watering them, and see which ones lived the longest. There’s never been a collaborative approach where physiologists and soil scientists have been involved. So researchers have imposed this harsh, biologically irrelevant stress where it’s basically been an attrition study.” Green says he hopes in his research to use the soil as a feedback mechanism to maintain a stress level that mimics what exists in nature.

Data acquisition a cabinet setup for green's expanded experiment

Data Acquisition Cabinet setup for Green’s expanded experiment.

The Pilot Study

Green used volumetric water content sensors, matric potential sensors, as well as column tensiometers to monitor soil moisture conditions in a greenhouse experiment using 182 cm tall polyvinyl chloride (PVC) growth tubes and homogenous growth media. Measurements were taken four times a day to determine volumetric water content, soil water potential, senescence, biomass, shoot, root ratio, rooting traits, yield components, leaf water potential, leaf relative water content, and other physiological observations between moisture limited and control treatments.

Soil Media: Advantages and Disadvantages

To solve the problem of differing soil types, Andrew and his team chose a homogeneous soil amendment media called Profile Greens Grade, which has been extensively studied for use in space and other applications. Green says, “It’s a very porous material with a large particle size. It’s a great growth media because at the end of the experiment you can separate the roots of the plant from the soil media, and those roots can be measured, imaged, and studied in conjunction with the data that is collected.” Green adds, however, that working with soil media isn’t perfect: there have been hydraulic conductivity issues, and the media must be closely monitored.

What’s Unique About this Study?

Green believes that because the substrate was very specific and his water content and water potential sensors were co-located, it allowed him to determine if all of his moisture release curves were consistent. He says, “We try to pack these columns to a uniform bulk density and keep an eye on things when we’re watering, hoping it’s going to stay consistent at every depth. So far it’s been working pretty well: the water content and the water potential are repeatable in the different columns.”

Irrigation setup for the expanded study with research data cabinet

Entire Irrigation setup for the expanded study.

Plans for the Future

Green’s pilot study was completed in the spring, and he’s getting ready for the expanded version of the project: a replicated trial with wild relatives of wheat. He’s hoping to use soil moisture sensors to make automatic irrigation decisions: i.e. the water potential of the columns will activate twelve solenoid valves which will disperse water to keep the materials in their target stress zone, or ideal water potential.

The Ultimate Goal

The ultimate goal of Green’s research is to breed wild species of wheat into productive forms that can be used as farmer-grown varieties. He is optimistic about the results of his pilot study. He says, “Based on the very small unreplicated data that we have so far, I think it is going to be possible to develop a repeatable method to screen these materials. With the data that we’re seeing now, and the information that we’re capturing about what’s going on below ground, I think being able to hold these things in a biologically relevant stress zone is going to be possible.”

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Oct 9

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Water Content helps Turf Growers find Water/Nutrient Balance

Many athletes don’t like artificial turf. They say it’s hot, uncomfortable to run on, causes burns when you slide or fall on it, and changes the way a ball moves. Professional women’s soccer players even started a lawsuit over FIFA’s decision to use artificial turf in the 2015 Women’s World Cup.

Soccer players running after the soccer ball on a green field

Soccer players on natural turf.

Some universities—including Brigham Young University—have responded to athlete concerns by using natural turf fields for practice and in their stadiums. But the challenge is to develop plants and management practices for natural turf that help it stand up to frequent use and allow it to perform well even during the difficult fall months. It’s a perfect research opportunity.

BYU turf professor and manager of BYU sports turf, Bryan Hopkins and his colleagues in the Plant and Wildlife Department, have been able to set up a new state-of-the-art facility to study plants and soil in both greenhouse and natural conditions. The facility includes a large section of residential and stadium turfgrass.

Before Soil Sensors

Initially, BYU maintained the turf farm grass on a standard, timer-based irrigation control system, but over time they realized that understanding the performance of their turf relative to moisture content and nutrient load is crucial. Last year during Memorial Day weekend their turf farm irrigation system stopped working when no one was around to notice. During those four days temperatures rose to 40 C (100 F), and the grass in the field slipped into dormancy due to heat stress. In response, Dr. Hopkins began imagining a system of soil moisture sensors to constantly monitor the performance of the turf grass. He wanted not only to make sure the turf never died but also to really understand the elements of stress so they could do a better job growing healthy turf.

Sensors Give a Clear Picture

Soon afterward, a team of scientists, including fellow professor Dr. Neil Hansen, installed volumetric water content (VWC) and matric potential sensors at two different sites: one in the sports turf and one in a residential turf plot. Each plot had two installations of sensors at 6 cm and 15 cm, along with VWC only at 25 cm, to measure water moving beyond the root zone. Combining these measurements, they could clearly see when the grass was reaching stress conditions and how quickly the turf went from the beginning of stress (in terms of water content and time) to permanent wilting point. In addition, ancillary measurements of temperature and electrical conductivity provide an opportunity for modeling surface and root zone temperature as well as fertilizer concentration dynamics.

Researcher digging a dirt canal and installing sensors

Installing water content sensors at the BYU turf farm.

Errors Revealed

What the researchers learned was that they were using too much water. Dr. Colin Campbell, a METER research scientist who worked with BYU on sensor installation, comments, “We found in the first year that the plants never got stressed at all. So this year, the researchers allowed the water potential (WP) at 6 cm to drop into the stress range (~ -500 kPa) while observing WP at 15 cm (-50 kPa to -60 kPa). We hope this approach will reduce irrigation inputs while creating some stress in the grass in order to push the roots deeper.”

What’s happening with the water?

Dr. Campbell’s favorite part of the sensor data was the detailed picture it gave of what was happening with the water in the sandy soil (Figure 1). He says, “Most people believe that they have an intuitive feel for water availability in soil. If we were only using water content sensors, seeing a typical value of 20% would lead us to believe we were comfortably in the middle of the plant available range (A). But in this study, using our colocated soil water content and soil water potential sensors, the data showed readings over 15% VWC were too wet to affect the WP (B). However, once WP visibly changed, it quickly moved toward critical stress levels (C, -1500 kPa is permanent wilting point); it only took two days for the water potential to change from -8 kPa to -1000 kPa. A subsequent dry period (D) shows similar behavior, but this time the 15 cm WP drops to near -1000 kPa.”

Figure 1

The plant stress levels were reached surprisingly quickly in this soil because its sand composition has a lot of large pores and not very many small ones (Figure 2). Campbell explains, “The large pores store water that is not held tightly due to low surface area, so the water is freely available. But at around 10% VWC all the water from the large pores is used up. As the soil dries beyond that, the water is held tightly in small pores and becomes increasingly unavailable. This is clear in the moisture release curve. We see almost no change in water potential as the soil dried to 16% VWC, but from 10% down to 7%, the water potential reached permanent wilting point, and it happened in just over a day.”

Figure 2

What the Future Holds:

The researchers wanted to make sure that if they went down to certain stress levels, they wouldn’t cause harm to the plants, so this year, they installed a weather station to monitor evapotranspiration and calculate irrigation application rates. They also began measuring spectral reflectance to monitor changes in leaf area (NDVI) and photosynthesis (PRI). This will enable them to see the impact on the plants as the turf is drying down. “In the future,” says Campbell, “we hope that both commercial and residential turf growers will be able to more effectively control their irrigation and nutrients based on what we find in this study.”

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Sep 25

Can a Leaf Wetness Sensor Distinguish Fog From Dew?

The Namib Desert on the Southwestern coast of Africa is hyper-arid in terms of rainfall but experiences frequent coastal fog events. The fog has been suggested to provide sufficient water for survival to certain plants which are endemic to the Namib, some of which occur only in the fog zone (up to 60 km inland).

Dr. Keir Soderberg wanted to measure how much fog water plants were taking up either through surficial roots or their leaves.

Dr. Keir Soderberg, former researcher at the University of Virginia (now a consultant at S.S. Papadopulos & Associates), wanted to use stable isotopes to measure how much fog water plants were taking up either through surficial roots or their leaves. To enrich his data set, he decided to use leaf wetness sensors to show when the fog was occurring. He also wondered if he could use the leaf wetness sensors to distinguish between fog and dew.

The Namib Desert

Keir set up five fog monitoring stations along a climate gradient in the central Namib. Each measured leaf wetness, air temperature, and relative humidity measurements along with solar radiation and soil parameters (moisture, temperature, and electrical conductivity). Stable isotope analysis of samples was also used to help quantify the amounts of fog, groundwater, and soil water that plants were using.

Dew or Fog:

Keir says, “We began collecting one-minute data to look at the different patterns of how the water was being deposited on the leaf wetness sensor. The dew tended to be more of a gradual wetting, but with the fog you would see these cyclical waves of steep wetting and then a little bit of a drying on the sensor.” Keir says he could look at those patterns and correlate them with visual evidence from his visits to the Namib during fog or dew events, though those wetting patterns may be specific to this location.

Measuring Volume:

Keir also tried to determine the volume of water deposited on the leaf wetness sensors. He did a calibration in the lab by spraying water on the sensor and then weighing it. He said, “It was sort of a trial and error thing. I found the performance was definitely sensor specific. You have to get an individual calibration, but I felt the uncertainty could be controlled.”

In comparing different methods of measuring fog deposition, Keir concluded that it is difficult to compare across measurement methods. “There’s a lot of variability between methods, even if you are confident in your own device and its accuracy.” This gives the advantage to the most common measurement device, the Standard Fog Collector, since much of the work done through the years has used these instruments. However, the cylindrical-style collectors have the advantage of being insensitive to wind direction.

Future Data:

In spite of this, Keir admits he’s still interested in seeing if he can get good dew collection data from leaf wetness sensors. He says, “I went on from Namibia to a research station in Kenya where we had an eddy covariance flux tower. Though there is no fog in Kenya, I convinced them to put leaf wetness sensors up and down the tower to collect data on dew deposition. We left the sensors out there and have been collecting one-minute data for a while. There’s this massive dataset out there that we still need to look at.”

Keir collaborated on a paper for The Journal of Arid Environments, called “The Nature of Moisture at Gobabeb, in the Central Namib Desert,” a compilation of different fog and dew collection techniques over the years, including leaf wetness sensors, for automating the identification of fog events. You can find it here. New fog monitoring stations are going up in the Namib through the programs FogLife and FogNet.

For a basic understanding of the role that fog plays in plant and ecosystem processes, read this article by Dr. Chris Still, who has studied this issue for many years in the Channel Islands National Park off of the coast of California.

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Aug 14

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The Potential of Drones in Research

Someday soon, multi-rotors will execute pre-programmed flight paths over several hundred research plots collecting daily data and sending it back to a computer while researchers sip their morning coffee. Researchers and growers won’t need to know anything about flying: the drones will fly themselves. This is the dream.

One UAV (unmanned air vehicle) industry leader at the above drone demonstration commented, “The truth is that this is where agriculture (and research) is going, and I don’t mean ‘Tomorrowland’ going–I mean it’s pretty much there. The only thing that’s holding us back is a permit from the FAA for autonomy, and that’s because the FAA is slowly backing into this UAV piece because we have the busiest general aviation sky in the world. But really, what you should have in your mind is multiple units operating with a single operator in a control vehicle.” The above UAV was extensively tested in California’s NAPA valley with results soon to be published online.

In this blog, a METER scientist and an instrumentation engineer give their perspectives on what needs to happen before drones reach their full research potential.

Drone Hexacopter

What are the advantages of drones for researchers?

Dr. Colin Campbell, research scientist-

One of the biggest challenges of work in the field is variability: low spots, high spots, sandy soil, clay soil, hard pans beneath the surface in some areas and not in others. This results in highly variable performance in crops. In addition to that, even when you have good homogeneity in a field, you might have differences due to irrigation or rainfall. If we want to improve agriculture, one thing that we have to do is be able to come out with better tools to be able to visualize the field in more than a single dimension. In order to do this right now, students go out and take plant measurements all day, every day, all summer long. The advantage of a drone is that you could do flyovers of a field, monitoring the traits that you’re interested in using reflectance indices that would normally take days of work.

What are the obstacles to progress?

Greg Kelley, mechanical engineer, and drone hobbyist-

Recently, the FAA has come out with a set of guidelines for the industrial use of drones: flying machines have to stay under a certain ceiling (500 ft; 150 m), and they have to be flown in the line of sight of the operator. The naive thing about those policies is: how much control does the operator have over the drone anyway? It used to be that with your remote control, you were moving the control surfaces (flaps, rudder, etc) on the aircraft, but this is changing. The onboard computer performs things like holding a stable altitude, maintaining a GPS location, or auto-stabilization (it keeps the aircraft level, even when a gust of wind comes). Those are degrees of control that have been taken away from the operator. Thus, according to the level of automation that the operator has built into the system, he may not be in direct control at all times. In fact, these machines are being developed so that they can fly themselves. From my perspective, the FAA regulations are going to have to evolve along with the automation of drones in order to allow the development of this technology in an appropriate way.

Drone with eight rotors.

What needs to happen before drones reach their full potential?

Dr. Colin Campbell–

Even if we get the flexibility required with drones, we’ve got to get the right sensor on the drone. On the surface, this seems relatively simple. Sensors to measure spectral reflectance are available in a package size that should easily mount on a drone platform. But, there are still many challenges. First, current spectral reflectance sensors make a passive reflectance measurement, meaning we’re at the mercy of the reflected sunlight. Clouds, sun angle, and leaf orientation, among other things, will all affect the measurement. There are several groups working on this (just search “drone NDVI” on the internet), but it’s a difficult problem to solve. Second, drones create a spectral reflectance “map” of a field that needs to be geo-referenced to features on the ground to match measurements with position. Once data are collected, the behavior of “plot A” can only be determined by matching the location and spectral reflectance of “plot A.” Different from the first challenge, this is more related to programming than science but is still a major hurdle.

Despite these challenges, drones promise incredible benefits as an agricultural and environmental measurement tool. As one industry leader at the drone demonstration put it, “the complexity of the problems that agriculture faces and the opportunities for efficiencies are vast. It will require ongoing engagement, next year and the year after that. There are a lot of questions to be answered and the efficacy is yet to be determined, but it’s exciting to watch the UAV helicopter and where it’s going.” Both Campbell and Kelley agree that significant advances will be made within the next few years.

Read about an ROI calculator that’s been created to help growers quantify whether the benefits of using a drone will exceed their costs.

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May 23

Gore-Tex, House Wrap, and Stomatal Conductance

Want to develop an appreciation for Gore-Tex? All you need is five minutes in a rubber raincoat. But how do you know whether the North Face knock-off you’ve just purchased in China for a ridiculously low price is Gore-Tex or rubber? If you’re a METER researcher, you dash back to your hotel room and clamp a porometer onto the fabric.

The leaf porometer was designed to measure stomatal conductance in leaves. It’s typically used by canopy researchers to relate stomatal resistance to canopy attributes like water use, water balance, and uptake rates of herbicides, ozone, and pollutants. Yet, from the beginning, Dr. Gaylon Campbell, the porometer’s designer, saw the possibilities: “Give this to someone with only a passing interest in research, a ten-year-old kid for example, and they’ll go around the garden and come back with some really interesting observations,” he said. “There are lots of questions about what loses water and what doesn’t that you can answer with this instrument.”

Researcher Clamping a LEAF POROMETER onto a Leaf in a Forest

SC1 Leaf Porometer

Dr. Campbell was probably thinking the questions would be about organic material—but it hasn’t always turned out that way. By putting a wet paper towel on one side of an inorganic material and clamping the towel and the material into the porometer head, you can measure how well water vapor diffuses through the material. Using this strategy, the researcher in China discovered that his raincoat was pretty much impermeable (unlike real Gore-Tex, which is a good vapor conductor). Spotting the fake North Face coat is now a favorite part of METER’s canopy seminar. And the coat is not the only leafless item that has been tested. “People will clamp the porometer on just about anything,” Doug Cobos, a METER research scientist, admitted. He himself grabbed it when a local contractor brought in a sample of some supposedly unique house wrap.

Siding is supposed to protect a house from the elements, but most building codes now require that houses be wrapped under the siding. House wraps provide a secondary defense against liquid water and increase energy efficiency by preventing drafts. As with raincoats, high-performance house wrap needs to repel water and stop wind while remaining permeable to water vapor.

A House Under Construction with Trees Around it

House under construction with protective wrap under the siding.

The practice of applying a sheathing of tar paper under siding is a hundred years old, but in the last fifteen years, high tech house wraps made from polypropylene in combination with a push towards energy efficiency have made the house wrap market big and competitive. Upstart wraps try to gain market share through innovation and the one brought in by the local contractor came along with an outlandish claim. According to the manufacturer’s rep, this plastic wrap would allow water vapor to diffuse out while preventing any from diffusing in. Some builders might have scratched their heads and moved on. Our local man decided to check it out. He brought a sample of the mystical wrap to Decagon. Out came the porometer and a quick scientific study of house wrap was born.

Dr. Cobos tested industry standard Tyvek house wrap along with the great one-way pretender. The results? “The vapor conductance of the new material was basically the same, regardless of which side of the material faced wet filter paper,” Dr. Cobos said. “And, in fact, the material didn’t diffuse well at all. Its conductance was similar to cheap perforated plastic. It didn’t come close to the performance of Tyvek.” Ultimately, the newfangled wrap was retested by the manufacturer and taken off the market.

Probably the porometer’s best and highest use is still in canopy research, but it still gets pulled out to measure whatever seems interesting, organic and inorganic alike. That dovetails with Dr. Campbell’s vision of it as a tool for routine use in canopy studies—and everywhere else. Can you use it on yourself? “Oh sure,” says Dr. Campbell. “People clamp the porometer on their fingers all the time. That’s a quick way to see if it’s working.” He grins. “Maybe you could use it as a lie detector on your kids.”

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Mar 9

Could This Farming Practice Make Food Grown in Fukushima Safe?

March 11, 2015 marks four years since the Fukushima disaster. What have we learned?

Shortly after the Fukushima disaster, we donated some of our sensors to Dr. Masaru Mizoguchi, a scientist colleague at the University of Tokyo. He is using the equipment to contrive a more environmentally friendly method to rid rice fields in the villages near Fukushima of the radioactive isotope cesium 137.

Over the last three years, government contractors removed 5 cm of topsoil from fields in order to extract the radioactive isotope. The topsoil has been replaced with sand. The problem with this method is that it also removes most of the essential soil material, leaving the fields a barren wasteland with little hope of recovery anytime soon. Topsoil removal may also prove ineffective because wild boars dig up the soil to root for insects and larvae. This presents a problem in the soil stripping method, as it becomes impossible to determine exactly where the 5 cm boundary exists. In addition, typhoons and heavy rains erode the sand surface raising safety and stability concerns.

Currently, bags full of radioactive topsoil are stacked into pyramids in abandoned fields. An outer black bag layer filled with clean sand is placed around the outside to prevent radiation leakage. The government has promised that these bags will be removed and taken to a repository near the destroyed reactor, but many people don’t believe that will happen as the bags themselves only have a projected life of 3-5 years before they start to degrade. More of these pyramids are being built around Iitate village every day, which is a source of uneasiness for many people that are already cautious about returning.

Dr. Mizoguchi and his colleagues have come up with a new “flooding” method now being tested in smaller fields that can save the topsoil and organic matter while at the same time removing the cesium, making the land usable again within two years. The new method floods the field and mixes the topsoil with water, leaving the clay particles suspended. Because the cesium binds with the clay, they can drain the water and clay mixture into a pre-dug pit and bury it with a meter of soil after the water has infiltrated. After one year of using this method, the scientists saw that the cesium levels in the rice had gone down 89%. And in situ and laboratory instrumentation have shown that two years after cesium removal, the plants’ cesium uptake is negligible, and the food harvested is safe for consumption.

Dr. Mizoguchi standing by a sensor station containing Decagon sensors

Dr. Mizoguchi is monitoring the surrounding forests with our canopy and soils instrumentation in order to determine if runoff from the wilderness areas will return cesium to the fields and what can be done about it. He’s figured out a way to network all the instrumentation and upload data directly to the cloud. Still, even if this technology and new methodology work, will people around the world ever feel safe eating food grown near Fukushima? Dr. Mizoguchi says, “I believe that the soil is recovered scientifically and technically. However, harmful rumors will remain in the public mind for a long time, even if we show the data that proves safety. So we must keep showing the facts on Fukushima based on scientific data.”

Resurrection of Fukushima Volunteers using Dr. Mizoguchi's method to rehabilitate small farms

Resurrection of Fukushima volunteers use Dr. Mizoguchi’s method to rehabilitate small farms

Incredibly, each weekend a volunteer organization of retired scientists and university professors use their own money and time to travel out to small village farms. There they labor to rehabilitate the land using Dr. Mizoguchi’s method. One of the recipients of this selfless work is a 72-year-old farmer who took his nonagenarian mother and returned to their home to fulfill her heartfelt plea that she could live out her final years outside the shadow of a highrise apartment (see this story in the video above). We are honored to be a part of this humanitarian effort.

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Dec 22

Measuring Osmotic Sap Water Potential

Sometimes networking with new scientists at conferences and workshops can pay dividends in terms of new ideas. Steve Garrity and I recently attended and taught practicum sessions at the PEPg (Plant Environmental Physiology group) Ecophysiology Workshop. The mission of this workshop was twofold: to invite the world experts on plant physiology measurements to come and lecture, and to invite the manufacturers to teach about instrumentation and provide hands-on training.

Workshop participants check the water potential of soil with a UMS T5 mini-tensiometer.

With three sessions per day using METER instrumentation and only two of us, neither Steve nor I could teach about leaf water potential using the WP4C chilled mirror dew point instrument. So, we asked another scientist who is an expert in plant water relations to teach it for us. Not only did he do a great job of teaching about measuring leaf water potential using a hygrometer, but he also inspired us to take another look at how to make this measurement as we learned about its importance to his research (to learn more about how to do this, watch our virtual seminar).

He’s developed a procedure where you can freeze the leaf and break all of the cells so you are left with the cell water (the symplastic water).

Later in the conference, this same scientist gave a talk about the importance of osmotic potential. He’s developed a procedure where you can freeze the leaf and break all of the cells so you are left with the cell water (the symplastic water). He was able to squeeze that sap out and test it in a thermocouple psychrometer, where he established a relationship between how tolerant plants are for drought and what their osmotic sap water potential (turgor loss point) was. We have made many of those sap measurements but had not used them in this manner. That’s really interesting to us at METER because we were unaware of this relationship, and we have now found another use for osmotic potential measurements in leaves.

We would never have realized this new idea without the help of our colleague. Meeting with other scientists at conferences and talking over ideas can be really important. Have you ever struck gold in terms of coming up with new ideas for research, funding, or inventing new research tools at a conference you’ve attended?

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Dec 15

Despite Drawbacks, Scientific Collaboration Pays Off

Though collaboration can fuel innovation and increase the relevance and complexity of the scientific questions we study, I’ve noticed it does have its ups and downs. The highs and lows we’ve run into on our research projects may help others avoid some of the pitfalls we experienced as many diverse groups tried to learn how to work together.

Researchers discussing science at the Lytle Ranch Preserve, a remarkable desert laboratory located at the convergence of the Great Basin, Colorado Plateau, and Mojave Desert biogeographical regions.

There can be bumps in the road when collaborating with companies who want to test their product. Being at the forefront of innovation means that untested sensors may require patience as you work out all the bugs together. But from my perspective, this is part of the fun. If we are late adopters of technology, we wouldn’t get to have a say in creating the sensors that will best fit our projects as scientists.

Collaborating scientists can also sometimes run into problems in terms of the stress of setting up an experiment in the time frame that is best for everyone. During our experiment on the Wasatch Plateau, we had six weeks to get together soil moisture and water potential sensors, but our new GS3 water content, temperature, and EC sensors had never been outside of the lab. In addition, we planned to use an NDVI sensor concept that came out of a workshop idea my father Gaylon had. We’d made ONE, and it seemed to work, but that is a long way from the 20 we needed for a long-term experiment in a remote location at 3000 meters elevation. In the end, it all worked out, but not without several late nights and a bit of luck. I remember students holding jackets over me to protect me from the rain as I raced to get the last sensor working. Then we shut the laptop and ran down the hill, trying to beat a huge thunderstorm that started to pelt the area.

Desert-FMP Researchers at the Lytle Ranch Preserve

Other challenges of scientific collaboration present organizational hardships. One of the interesting things about the interdisciplinary science in the Desert FMP project is the complexity of the logistics, and maybe that’s a reason why some people don’t do interdisciplinary projects. We are finding in order to get good data on the effects of small mammals and plants you need to coordinate when you are sampling small mammals and when you’re sampling plants. Communicating between four different labs is complicated. Each of the rainout shelters we use cover an area of approximately 1.5 m2 . That’s not a lot of space when we have two people interested in soil processes and two people interested in plants who all need to know what’s going on underneath the shelter. Deciding who gets to take a destructive sample and who can only make measurements that don’t change the system is really hard. The interesting part of the project where we’re making connections between processes has required a lot of coordination, collaboration, and forward-thinking.

In spite of the headaches, my colleague and I continue to think of ways we can help each other in our research. Maybe we’re gluttons for punishment, but I think the benefits far outweigh the trouble we’ve had. For instance, in the above-mentioned Desert FMP project we’ve been able to discover that small mammals are influential in rangeland fire recovery (read about it here). We only discovered that piece of the puzzle because scientists from differing disciplines are working together. In our Wasatch Plateau project, my scientist colleague said it was extremely helpful for him to be working with an instrumentation expert who could help him with setup and technical issues. Also, we’ve been able to secure some significant grants in our Cook Farm Project (you can read about it in an upcoming post) and answer some important questions that wouldn’t have occurred to either one of us, if we hadn’t been working together. In addition, solving problems that have cropped up in our projects has spurred us on to a new idea for analyzing enormous streams of data in near-real time. (read about it here).

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Nov 13

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Complex Scientific Questions Yield Better Science in Desert FMP Project

The Desert FMP project originated from a discussion between pretty divergent scientists: Rick Gill, a BYU ecologist, another scientist who works on soil microbes, a plant physiologist, and a mammalogist who researches small mammals.

Tree fire in Rush Valley

In an interview Rick said, “We started talking one day about the transformations that have occurred in the arid West over the past 100 years. One of the things we are really interested in is fire. How do ecosystems recover after fire? What’s the role of water in rangeland recovery? And the unique piece of this is: what’s the role of small mammals in this process? We may never have thought of that question, or the complexity of researching how all of our questions work together in a system, if scientists from different disciplines hadn’t decided to collaborate.”

Rush Valley research site. Five replications with four treatments: burned/unburned and small mammal/no small mammal. What’s interesting for us is that you can see that in the burned plots (the light brown) there are strong differences in the amount of the bright green plant—halogeton—that was present and it is systematically associated with the presence of small mammals. Here is the logic: In the spring, the presence of small mammals suppressed the cheatgrass and to some extent halogeton; in the absence of halogeton, cheatgrass ran wild. The cheatgrass transpired away all of the water and the halogeton that had germinated all died before it could flower.

As the experiment unfolds it is becoming clear that small mammals play a larger role in ecosystem recovery from fire than originally thought. The scientists have used their observations to hypothesize that small mammals eat the seeds and seedlings of two invasive species. This ends up setting the vegetation along a very different trajectory than when small mammals are absent following fire. Rick says, “We have discovered this complex but interesting interaction between water, fire, and small mammals. The first year after the fire, a really nasty range forb moved in called halogeton, which is toxic to livestock. Halogeton also accumulates salts in the upper soil profile that will cause failure in native plant germination. Cheatgrass has also moved in which makes the area more prone to fire as it connects the sagebrush plants with flammable material. But what’s interesting is in treatments where mammals were present, the densities of both halogeton and cheatgrass were much lower than where small mammals were absent.

Plot water potential comparison using matric potential sensors between Mammal (blue) and no mammal (red) over time. With no mammals to control cheatgrass, it depleted soil water availability below no mammal treatment and consequently halogeten was not able to grow.

“The other really important thing is that cheatgrass and halogeton have different growth patterns. Cheatgrass germinates in the Fall. It reaches peak biomass early in the growing season and then dies off leaving a blanket of dead, highly flammable vegetation. Halogeton germinates early in the growing season and remains relatively small until early Autumn when it bolts. These are things that will be really easy to pick up using NDVI sensors, which are sensitive to the amount of green vegetation within the field of view of the sensor. We are also using a system that we’ve designed to manipulate precipitation input. This will enable us to connect water availability to the success of two invasive plants that have negative impacts on rangelands. And with these same treatments we’re going to be able to tease out when in the year and to what extent small mammals are influencing the ecosystem by eating the seeds or the plant and at what stage.”

“Until I saw it in the field, the question of mammals being influential in rangeland fire recovery had never occurred to me. We only discovered that piece of the puzzle because scientists from differing disciplines are working together.”

Below are two virtual tours of the site: