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Posts tagged ‘Water content’

Mar 18

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Can Wastewater Save The United Arab Emirates’ Groundwater?

The hyper-arid United Arab Emirates (UAE) has a rapidly dwindling supply of groundwater, and that water is becoming increasingly saline.

Image of the city of Dubai at night on the coast of the UAE

Dubai is situated on the coast of the UAE.

With very little recharge and irrigation comprising 75% of groundwater use, natural water resources in this region are disappearing fast.  PhD candidate Wafa Al Yamani works for the Environmental Agency of Abu Dhabi, which has contracted with Plant and Food Research in New Zealand to investigate using treated sewage effluent and groundwater for irrigating the desert forests along their motorways.  

Sidr tree plantation in the UAE forest in the sand

Sidr trees in the UAE forest.

The Desert Forests

The UAE desalinates all the water for their cities, so the tertiary treated sewage effluent from these cities could be a viable resource, replacing some groundwater for irrigation of the desert forests. These forests perform a wide range of ecosystem services from sand stabilization along all UAE motorways to harboring a great deal of biodiversity.  There is also a cultural association with the forests.  The original ruler of the UAE, Sheikh Zayed, embarked on a program in the 1970s of “greening the desert,” so the people see the desert forests as a legacy of their founder.

Infiltrometer pushing sand and being measured

Infiltrometers were used to examine how the drip irrigation system worked.

Measuring Water Use:

Wafa and her PhD advisor, Dr. Brent Clothier, had a goal to minimize groundwater use and maximize value by quantifying the irrigation needs of the UAE’s five most important desert-forestry species.  They also wanted to determine the impact of treated sewage effluent on forest growth and health.  They used infiltrometers to examine how the drip irrigation system worked.  Dr. Clothier says, “These soils have hydraulic conductivities of between 2 and 5 meters an hour.  They are highly permeable desert sands.  We can find out how wide the bulb (the wetted area underneath an irrigation dripper) is and how deep the water will travel by using an infiltrometer to look at the hydraulic properties of the soil.”  Dr. Clothier has also developed software to predict water movement radially, with depth and with the time that the drippers are on.  He comments, “We’ve now got a setup of two drippers per tree, and we will use that in the future for modeling how the trees are taking up water from the root zone.”

Tree with 20cm dykes accessing the dripper water

Researchers built dykes of 20 cm to stop surface redistribution of dripper water.

The scientists used a heat pulse method to measure tree water-use by comparing sap flow with evaporative demand (ETo).  They used Time Domain Reflectometry (TDR) to measure soil water content, and they have developed a “light stick” using light sensors to detect the shadow area of the trees to measure trees’ leaf area in order to predict the crop factor that will enable prediction of tree water-use from ETo.

Next week:  Find out how Wafa and her team use infiltrometers to predict dripper behavior and how the treated effluent resolves salinity issues.

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Feb 25

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Irrigation and Climate Impacts to the Water-Energy Balance of the WI Central Sands (Part II)

Due to controversy over the growing number of high capacity wells in the Wisconsin Central Sands, University of Wisconsin PhD student, Mallika Nocco, is researching how agricultural land use, irrigation, and climate change impact the region’s water-energy balance (see part I).  This week, read about her challenges installing lysimeters below the root zone, how she used a GPS system that can find the lysimeters within a half-inch of accuracy, and her surprising conclusions.

Irrigation sprinkler line set up in a grassy field

This relatively small ecological region has gone from 60 high capacity wells in 1960 to over 2,500 today.

Below the Root Zone

Nocco says getting the lysimeters below the root zone was a major challenge.  “We tried a couple of things, but we settled on installing all the lysimeters with an 18-inch auger that would drill a hole slightly bigger than the whole lysimeter.  We dug an 80 cm trench to the top of the monolith zone. Then, we pounded the drain gauge divergence control tube to 1.4 m to obtain an intact monolith, wherever it was possible to do so. We also stratified soil moisture sensors at 10, 20, 40, and 80 cm.  We used heavy equipment to slowly lift out the monolith, dig out the soil below, and place it back in, keeping  track of all of the different soil horizons, and backfilled as close to the bulk density as we could.”

Researcher filling a hole with dirt and a tube with dirt

Passive capillary lysimeter installation

Finding the Lysimeters with GPS

Typically, scientists bury lysimeters close to the edge of the field so they are easy to locate, but Nocco was concerned that they would prejudice their data due to the donut effect of center pivot irrigation: more irrigation hits the center of the field with less irrigation toward the edges. She comments, ”When I installed the first ten lysimeters, I had not yet come up with a way to find everything. Those instruments are all about 15 meters from the field edge so that I could triangulate measurements and find them during cultivation.  But then I met an extension scientist at the university who had access to an RTK GPS system, which can locate instrumentation within a half-inch of accuracy.  With his help and training, we were able to install the rest of the lysimeters at more random spots throughout the field.”

Irrigation sprinkler line set up in a pastor or field

Nocco was concerned that they would prejudice their data due to the donut effect of center pivot irrigation.

Surprising Conclusions

Nocco says that ET and differences in crop physiology do not explain or account for all of the variability that she saw in groundwater recharge.  Her team did a particle size analysis on the soils adjacent to the lysimeters, and she comments, “We thought that the greater the relative sand content in the soils, the more recharge we would have seen, but what we are seeing is the opposite.  The particle size analysis reveals a negative linear correlation between potential recharge and sand content. The more silt there is in these lysimeters, the more volume of recharge.  What I’m curious about now is if we’re seeing a greater volume of recharge in the siltier spots from flux convergence.  I’m trying to obtain the time series data from the pressure transducers to see if maybe the sandier areas had less potential recharge, but perhaps drained faster.  I have seen a correlation between antecedent soil moisture content and particle size (with no correlation based on crop type).  So it also looks like the siltier soils are holding more water when the rain comes through.”

What’s Next?

Eventually, Nocco plans to use field-generated estimates of groundwater recharge and ET to parameterize and validate a dynamic, agroecosystem model, Agro-IBIS, simulating hydrological responses to climate and land use changes over the past 60 years. Nocco will then share the water-energy budgets and water quantity/climate simulations with stakeholders in the Wisconsin Central Sands area.

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Feb 17

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Irrigation and Climate Impacts to the Water-Energy Balance of the WI Central Sands (Part I)

Due to controversy over the growing number of high capacity wells in the Wisconsin Central Sands, University of Wisconsin PhD student, Mallika Nocco, is researching how agricultural land use, irrigation, and climate change impact the region’s water-energy balance.  She and her team have uncovered some surprising results.

Fisher women leans in for a kiss with a class 1 trout she caught

A class 1 trout stream has sufficient natural reproduction to sustain populations of wild trout at or near carry capacity.

Water Use Debate

There are class 1 trout streams in the Central Sands region, and some people worry that the increasing number of high capacity wells used for agriculture will reduce the water levels in those streams.  “Lake Huron has lost about 11 feet of water since 2000,” says one resident of the Central Sands area, “and water levels are continuing to drop.” In 2008, the small well he used to pump drinking water went dry, and he blames the high capacity wells.” (Aljazeera America)  On the other side of the debate, agriculture irrigated by these wells is extremely valuable to the state, and growers have taken quite a bit of time to understand the water cycle and their role in it. You can read about their water management goals and accomplishments here.

Updating Former Research

Irrigated agriculture wasn’t prevalent or profitable in the Wisconsin Central Sands until groundwater irrigation with high capacity wells became feasible in the 1950s.  Since then, this relatively small ecological region has gone from 60 high capacity wells in 1960 to over 2,500 today.

Mallika Nocco is studying potential groundwater recharge from irrigated cropping systems that use the wells, hoping to understand if the irrigation water is lost or returned to the groundwater.  She says, “Until now, we’ve been relying on models validated by two lysimeters in the 1970s. Champ Tanner (one of the fathers of environmental biophysics) designed the weighing lysimeters, and they were very accurate, but we wanted to do a larger scale study with multiple crops to get a handle on interannual variability and to improve our understanding of recharge in the region so we can do a better job of managing irrigation and groundwater.”

Lysimeter installation into a dirt and a field

Lysimeter installation into actively managed fields presented challenges that the research team had to overcome.

Measuring Recharge

Nocco used twenty-five drain gauge lysimeters to capture vadose zone flux under potato and maize cropping systems.  She monitored soil water (and temperature) flux by stratifying water content sensors from the soil surface to a depth of 1.4 meters.  She also estimated evapotranspiration (ET) using a porometer to measure stomatal conductance, in addition to obtaining micrometeorology, leaf area index, and gas exchange measurements.

Nocco and her team had to put their sensors in to avoid cultivation, so they extended the drain gauge PVC that comes up to the soil surface and removed it any time there was major fieldwork, whether it was tillage or planting, so that the area over the lysimeter got the same treatment as the rest of the agricultural fields.

Below the Root Zone

Nocco says getting the lysimeters below the root zone was a challenge.  Next week, read about how she solved that challenge, how she used a GPS system to find the lysimeters within a half-inch of accuracy, and about her surprising conclusions.

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Feb 11

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Estimating Relative Humidity in Soil: How to Stop Doing it Wrong

Estimating the relative humidity in soil?  Most people do it wrong…every time.  Dr. Gaylon S. Campbell shares a lesson on how to correctly estimate soil relative humidity from his new book, Soil Physics with Python, which he recently coauthored with Dr. Marco Bittelli.

Desert with trees and brush everywhere

Radioactive waste buried in steel containers will corrode if the humidity is too high.

A number of years ago a former student told me of a meeting he had with some engineers establishing a low-level radioactive waste repository in a desert area. The waste was to be buried, and at least some of it was in steel containers which would corrode if the humidity was too high. The engineers assumed the humidity in the soil would be pretty low because it was a desert, but they didn’t know how low. So, what is the relative humidity in soil? That sounds like it would be a hard thing to find out without measuring it, but it isn’t. Let’s apply a little physics to see what we can find.

The energy required to create an infinitesimal volume of water vapor can be found using the first law of thermodynamics. For an adiabatic system

Thermodynamics Equations

where dE is the energy required, p is the pressure, and dV is the volume change.

The Boyle-Charles law, which gives the pressure-volume relationship for a perfect gas, is

Thermodynamics Equations

where n is the number of moles of gas, R is the universal gas constant, and T is the kelvin temperature. Rearranging terms and taking the derivative of both sides gives

Thermodynamics Equations

This equation can be substituted for dV in the first equation, giving

Thermodynamics Equations

The total energy required to go from a reference vapor pressure, po (the vapor pressure of pure water) to the vapor pressure of the water in the soil, p is

Thermodynamics Equations

We can divide both sides by the mass of water. The left side then becomes the energy per unit mass of water in the soil, which we call the water potential. On the right side, the number of moles per unit mass is the reciprocal of the molecular mass of water, and the ratio of the vapor to the saturation vapor pressure is the relative humidity hr so the final equation is

Thermodynamics Equations

We can rearrange this and take the exponential of both sides, giving

Thermodynamics Equations

In the second version of the equation the molecular mass of water, the gas constant and the temperature (298K) have been substituted.

We can use this equation to find the range of humidities we would expect in soil. When soil is very wet, the water potential is near 0, so the humidity is exp(0) = 1. At the dry end, the soil is dried mainly by plant water uptake. Even desert soils support some vegetation. The soil near the surface will be dried by evaporation, but a few decimeters below the surface the lowest water potentials are those to which plants can dry them. The nominal permanent wilting point (lower limit of plant available water) is -1500 J/kg. Desert vegetation can extract water to lower potentials. If we say their lower limit is -2500 J/kg, then the humidity is

Thermodynamics Equations

so the relative humidity in the soil is around 98%. Sagebrush can go lower than -2500 J/kg. We measured -7000 J/kg under it at the end of the growing season. Even that, though, is around 95% humidity.

The conclusion is that the humidity in the soil is always near saturation, except in a shallow evaporation layer near the surface. I don’t remember what the engineers were expecting. I think anything above 60 or 70% was going to be a disaster for corroding the steel containers. I don’t know whether they believed the calculations or just went on thinking that desert soil is dry.

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Six short videos teach you everything you need to know about soil water content and soil water potential—and why you should measure them together.  Plus, master the basics of soil hydraulic conductivity.

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Feb 4

Predicting the Stability of Rangeland Productivity to Climate Change

Dr. Lauren Hallett, researcher at  the University of California, Berkeley, recently conducted a study testing the importance of compensatory dynamics on forage stability in an experimental field setting where she manipulated rainfall availability and species interactions. She wanted to understand how climate variability affected patterns of species tradeoff in grasslands over time and how those tradeoffs affected the stability of things like forage production across changing rainfall conditions.

field with species tradeoffs standing in the brush

Species tradeoffs could help mitigate the negative effects of climate variability on overall forage production.

Species Tradeoff

A key mechanism that can lead to stability in forage production is compensatory dynamics, in which the responses of different species  to climate fluctuations result in tradeoffs between functional groups over time. These tradeoffs could help mitigate the negative effects of climate variability on overall forage production.  Dr. Hallett comments, “In California grasslands, there’s a pattern that is part of rangeland dogma, that in dry years you have more forbs, and in wet years you have more grasses. I wondered if you could manage the system so that both forbs and grasses are present in the seed bank, able to respond to climate.  This would perhaps buffer community properties, like soil cover for erosion control and forage production in terms of biomass, from the effects of climate variability.”

Tradeoff in a green field, aerial view

In areas experiencing moderate grazing, there was a strong species tradeoff between grasses and forbs.

Manipulating Species Composition

Dr. Hallett capitalized on the pre-existing grazing manipulation that her lab had done over the previous four years.  The grazing she replicated for this study was experimentally controlled, making it easier to ensure consistency.  She built rainout shelters where she collected the water and applied it to dry versus wet plots.  She also manipulated species composition, allowing only grasses, only forbs, or a mix of the two.  These treatments allowed her to study changes in cover and biomass.

Hallett used soil moisture probes and data loggers to characterize the treatment effects of this experiment and to parameterize models that predict rangeland response to climate change.  She says, “I wanted to verify that my rainfall treatments were getting a really strong soil moisture dynamic, and I found the shelters and the irrigation worked really well.”  Along with above-ground vegetation, she collected soil cores and looked at nutrient differences in conjunction with soil moisture.  Since her field site is located within the Sierra Foothills Research and Extension Center, Dr. Hallett was able to rely on precipitation data that was already measured on-site.  

Results

Dr. Hallett found that in areas experiencing moderate grazing, there was a strong species tradeoff between grasses and forbs.  She comments, “I had a seedbank that had both functional groups represented, and those tradeoffs did a lot to stabilize cover over time.”

When Dr. Hallett replicated the experiment in an area that had a history of low grazing, she found that the proportion of forbs wasn’t as high in the seedbank.  As a consequence, there was a major loss of cover in the dry plots.  She explains, “When the grass died, there weren’t many forbs to replace it, and you ended up with a lot of bare ground. The areas that were lightly grazed had more litter, so initially, the soil moisture was okay, but as the season progressed into a dry condition and the litter decomposed, there wasn’t enough new vegetation to stabilize the soil.”  As a result, Dr. Hallett thinks in low-grazed areas it’s important to have an intermediate level of litter. She says, “You need enough litter to increase soil moisture, but not so much that it would suppress germination of the forbs because as the season progresses and gets really dry, if you don’t have forbs in the system, you lose a lot of ground cover.”

Surprises Lead to A New Study

Dr. Hallett was surprised that within her three treatments there seemed to be differences in when the functional groups were drying down the soil.  This inspired new questions, leading her to use her dissertation data to generate a larger grant through the USDA.  Her new study will perform extensive rainfall manipulations to measure the effects of early-season versus late-season dryout, and vary species within those parameters.  She says, “One of the reasons you have grass years versus forb years is the timing of rainfall.  For instance, if you have a really dry fall, you tend to have more forbs because their seedlings are more drought resistant.  Conversely, if you have a wet fall, you tend to see more grasses because you have continual germination throughout the season. So, the timing of rainfall matters in terms of what species are in the system.  We are going to look at the coupling between the species that gets selected for the fall versus what would be able to grow well in the spring, and we will be studying how that affects a whole range of things such as ground cover, above-ground production for forage, below-ground investment of different functional groups, and how these things might relate to nutrient cycling and carbon storage.”

You can read more about Dr. Hallett’s rangeland research and her current projects here.  

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Jan 14

Using Soil Moisture Sensors on Humans?

Dr. Stuart Campbell, professor of Biomedical Engineering at Yale University has been toying with the idea of using soil moisture sensors to measure tissue edema in human subjects.

Patients had wrapped in gauze with a tube

Tissue edema occurs when too much fluid leaks from your capillaries into your tissue.

He says he got the idea from Dr. Ken Campbell, former professor of Bioengineering at Washington State University:  “I was explaining to Dr. Campbell about the sensors METER makes, and he pointed out that there are many diseases where you might want to measure someone’s tissue edema, and it would be interesting to see if you could use a soil sensor in a wearable device to help doctors monitor swelling in their patients, much like a heart monitor monitors heart activity.”

Tissue Edema:

Tissue edema occurs when too much fluid leaks from your capillaries into your tissue. Capillaries, the smallest blood vessels in your body, are somewhat leaky, allowing the exchange of nutrients and waste between the tissue and the blood. The fluid that surrounds the blood cells is free to exchange across the capillaries, and edema will occur when too much fluid leaks out of the circulatory system into the tissue.  Edema can be caused by things like heart disease, pregnancy, or standing on your feet all day.  

What Makes the Fluid Leak?

In soil, water moves from high water potential to low water potential. Similarly, there are forces inside the circulatory system that cause the transfer of fluid between capillaries.  Your blood vessels have a certain amount of pressure that is generated by your heart.  If your blood pressure goes up, it can cause edema. Dr. Stuart Campbell says, “The actual fluid pressure is part of what decides how much fluid is pushed out, but it’s not that simple. Your blood has large proteins that are too big to get out of the capillary. That means the more water that leaves the capillary and moves into the tissue, the more concentrated those proteins become, which lowers the water potential (or osmotic potential) of the blood. This delicate balance is what prevents too much water from leaking out.  However, if you have a disease that tips this balance, either through high blood pressure or a condition that allows those proteins to leak out of the capillary, edema would occur because you don’t have the osmotic potential pulling the water back into the capillary and keeping the proper balance.”

Stuart Campbell operating on the heart for a medical procedure

Dr. Campbell thought it would be interesting to figure out if he could monitor the edema of heart tissue during one of the procedures.

The Heart Experiment:

Dr. Campbell decided to see if a soil sensor would work to measure animal tissue when he was working as a summer student in the Visible Heart Lab at the University of Minnesota.  Campbell says, “Similar to a human heart transplant, this lab is able to keep pig hearts alive outside the body.  The problem, however, is that they use a manmade solution instead of blood, and that imitation blood is not ideal. If the composition of the fluid is not perfectly adjusted, you can have problems with your experiments.  I thought it would be interesting to figure out if we could monitor the edema of the heart tissue during one of the procedures. I hooked up the soil probe and used it in one experiment where I put it in contact with the heart while it was beating.  There was, in fact, a change in output of that signal during the experiment.  But, because I only got one chance at it, it was inconclusive as to whether this was indicative of an imbalance in the composition of our artificial blood substitute.”  

An Anecdotal Experiment:

Still curious to see if the idea would work, Dr. Campbell decided to try one more experiment: this time on his wife who was experiencing edema symptoms after childbirth.  He says, “It occurred to me that this was an opportunity to try out the soil moisture probe one more time to measure tissue edema.  So each day, I would measure her ankles, putting the probe in flat contact with her skin while tightening a strap gently.”  Dr. Campbell says he watched the swelling go down as the numbers on the probe got smaller, and comments, “It was anecdotal evidence that at least in extreme cases, you might be able to get the soil probe to work.  But I still have questions, such as, how would you make sure that the probe was always touching the skin in the same way?  And, if the person got sweaty, would that change the soil probe reading?”  

Nurse measuring heart rate

There are millions of people in this country who have heart failure.

Why the Experiments Should Continue:

Though Dr. Campbell hasn’t had time to pursue the experiment further, he feels that if the idea works, it has the potential to improve lives and save our nation billions of dollars.  He says, “There are millions of people in this country who have heart failure.  Maybe they’ve had a blockage in one of their coronary arteries, or perhaps their heart is worn out because of age. You can tell when someone is in heart failure because when they lie down to go to sleep at night, all that fluid makes its way slowly from the ankles, through the legs, the torso, and eventually into the chest. The problem is that the lungs are very delicate, and when you have edema in the lungs, it’s almost like you have pneumonia.  This type of sensor could be an easy way for people to monitor themselves and manage their fluid intake and diet after they get home from the hospital.”  Dr. Campbell says this helps the economy because if people don’t manage their fluids, they have to return to the hospital so they can be supervised to eat correctly and regain the proper fluid balance. This ends up costing the economy billions of dollars unnecessarily.  He concludes, “Perhaps people just need to follow instructions, but it’s possible with better monitoring that the situation can be improved.”

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Jan 7

Using The Salt Balance Approach to Measure Soil Drainage

Understanding the amount of drainage that comes out of the bottom of the root zone and infiltrates into groundwater recharge is a very difficult measurement to do well. Drain gauges do a good job of it but on a small scale. Large lysimeters do an even better job, but are extremely expensive and complex.  There is an economical alternative, however, called the salt balance approach to measuring drainage.

Soil profile underneath canola

Soil profile underneath canola

The Salt Balance Approach

Since the majority of non-fertilizer salts in the soil solution don’t get taken up by plants, this salt can be used in soil as a conservative tracer.  This means that whatever salt is applied to the soil through rainfall or irrigation water is either stored in the soil or leaches through the profile with the soil water, enabling us to use conservation of mass in our salt balance analysis. The electrical conductivity of water (ECw) is directly proportional to the salt concentration, so ECw can be used in place of salt concentration in this analysis.  If you measure the EC of the water that’s applied to the soil, either through irrigation or precipitation,  as well as the EC of the water that’s coming out of the bottom of your profile, then you can calculate what fraction of the applied water is being transpired by the plants, and what fraction is draining out of the bottom.  This method is useful for measuring water balance at field sites.

To illustrate this concept, let’s work through a simple example.  A particular field received 40 cm of water through precipitation and irrigation.  The average ECw of the precipitation and irrigation water is 0.5 dS/m.  Measurements of ECw draining from the soil profile below the root zone indicate an ECw of 2.0 dS/m.  The drainage or leaching fraction can be easily calculated as :

ECw(applied) / ECw(drained) = 0.5 dS/m / 2.0 dS/m = 0.25

The amount of water drained can also be easily calculated as:

Leaching fraction * applied water = 0.25 * 40 cm = 10 cm

Measuring Pore Water EC (ECw)

One challenge to this approach is the measurement of water electrical conductivity itself.  Bulk EC is a relatively simple measurement, and several types of soil water content sensors measure it as a basic sensor output.  However, the electrical conductivity of water, called pore water EC (ECw), is more complex.  Pore water EC requires that it be either estimated from the bulk EC and soil water content or that a sample of pore water be pulled from the soil matrix and measured.  When estimated, pore water EC can contain considerable error.  In addition, removing a water sample and measuring the pore water EC is not easy. 

To learn more about measuring EC, read our EC app guide.

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Jan 1

Environmental Biophysics: Top Five Blog Posts in 2015

In case you missed our best blogs, below are the five most-viewed Environmental Biophysics posts in 2015.

Sunflowers in a sunflower field

Sunflower field in Hokkaido

Do the Standards for Field Capacity and Permanent Wilting Point Need to Be Reexamined?

We asked scientist, Dr. Gaylon S. Campbell, which scientific idea he thinks impedes scientific progress.  Here’s what he had to say.

Pine tree branch

Conifer

Environmental Biophysics Lectures

During a recent semester at Washington State University, a film crew recorded all of the lectures given in the Environmental Biophysics course. The videos from each Environmental Biophysics lecture are posted here for your viewing and educational pleasure.

Cherries on a cherry tree

Cherries

Sensor Data Improves Cherry Production

Dr. Khot and his postdoc, Dr. Jianfeng Zhou, are using leaf wetness sensors to determine if and how long water is present on cherry tree canopies after a rain event. Dr. Khot hopes that data from these sensors will help growers decide whether or not it makes sense to fly helicopters in order to dry the canopies.

Maple leafs on a maple tree

Maple leaf

What is the Future of Sensor Technology?

Dr. John Selker, hydrologist at Oregon State University and one of the scientists behind the Trans African Hydro and Meteorological Observatory (TAHMO) project, gives his perspective on the future of sensor technology.

Wet rocks on a riverbank with water flowing down through

Riverbank

Sensors Validate California Groundwater Resource Management Techniques

Michelle Newcomer, a PhD candidate at UC Berkeley, (previously at San Francisco State University), recently published research using rain gauges, soil moisture, and water potential sensors to determine if low impact design (LID) structures such as rain gardens and infiltration trenches are an effective means of infiltrating and storing rainwater in dry climates instead of letting it run off into the ocean.

Looking up at a tree canopy

Looking up at a tree canopy

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Dec 23

Reforestation Challenges Around the World

In the conclusion of our three part series on the reforestation of Banguet province in the Philippines, we asked Dr. Anthony S. Davis, Tom Alberg and Judi Beck Chair in Natural Resources at the University of Idaho, Loreca Stauber, one of the visionaries behind the project, and Kea Woodruff, former U of I Nursery Production and Logistics Associate, now at Harvard University, to explain some challenges associated with teaching reforestation to different cultures.

Ground view of a forest of bamboo looking up

Even with increased environmental awareness, we’re still losing almost thirty million acres of forest globally every year.

What are some of the cultural challenges?

Anthony: As I spend more and more time looking at international forests, I realize that we’re losing forests at a phenomenal rate. Even with all of our awareness about where we get supplies, where trees come from, where wood comes from, and where paper comes from, we’re still losing almost thirty million acres of forest globally every year. That’s terrifying to me. What’s even worse is that most of it comes from countries that don’t have environmental controls.  They don’t have systems in place that keep them from cutting down all the trees. Often, when we cut trees down for forestry, we replant. But, when you start to work in countries where that’s not valued or not part of the culture or the system, then a huge problem emerges.

How do you teach people to grow trees that can survive in their native terrain?

Anthony: There isn’t a lot of knowledge globally about how to grow high-quality tree seedlings. I’ve gotten really interested in the question of how to take a tree seedling which is grown in a nursery, where it essentially has all of the water and all of the nutrients it could possibly ask for, and get it into a condition where it’s likely to survive somewhere extremely harsh: with limited nutrients and water.  How do you get it to the point where it’s able to overcome those challenges?

There are two ways to look at that. One is to get more water to that seedling after it’s planted. The other is to make sure that the seedling you’re planting has its best possible chance of developing a root system that can access water that might not normally be available in those six inches where healthy roots are located when it’s first planted. Based on work that’s be done here at the University of Idaho in graduate student projects over the years, we found that if you can grow a seedling in a healthy manner in the nursery, it’s more likely to grow roots or access water that previously they might not have been able to access.

Researcher works on one of the water tanks that will supply water to the Benguet nursery in the Philippines

Working on one of the water tanks that will supply water to the Benguet nursery in the Philippines. The project is proceeding nicely after a series of setbacks: a destructive typhoon, slides that had to be cleared, 2 deaths, 1 funeral, and electrical power interruptions.

What challenges the plants after they leave the nursery?

Anthony: If that seedling can get roots down and access water, it starts to grow.  The beauty of reforestation, in general, is that it’s very simple; it can be very easy to get trees to grow. However, what often happens is you have a social element that overlaps the biological element. Some of it could be a lack of education, where people don’t understand that a large amount of foliage or leaves on a tree means that you need more water. You think about that image of success: people want to plant the biggest tree possible. That might work in a yard, but it really doesn’t work in a reforestation situation.

What are the challenges of establishing a nursery in a place like the Philippines?

Kea: In the place like the Philippines where resources aren’t necessarily as available, it becomes a huge challenge just finding the right kind of media or container. Also, there’s a decentralization of the knowledge resource itself. While we were there, we had the opportunity to meet with different government agencies, and there are definitely people who know a lot about the species that are available and how to grow them, but in terms of that information being disseminated and widely available to the public, that’s a challenge. The techniques that will be needed to actually produce a seedling resource need to be addressed.  

Loreca:  The basic thing is a good nursery. That has been a problem. In the past, the government, in an effort to green the Philippines, has given seedlings, but oftentimes, these seedlings are so poor in quality that they don’t survive in out planting.

Coffee beans thriving in the tropical Philippines

Coffee beans will thrive in the tropical Philippines.

How can you help other cultures to succeed at reforestation?

Anthony: During some work I was doing in the Middle East, in Lebanon, we found that communicating to people what a high-quality seedling became really important. You teach them about quality, defining it in terms of how much water a plant needs to survive, or how a plant has to grow in order to colonize a site.  We had a lot of success with the project there, getting people to understand that there was a problem in only looking at above ground information in terms of what makes a high-quality seedling. Really, when the roots are what’s driving survival, they’re looking at the wrong part of the picture.

How do you teach people to think beyond the nursery?

Anthony: Our work in Lebanon coincided with a project in Haiti. In Haiti, we had a former student who had been here at the University of Idaho who asked for help starting a nursery. These same conversations occurred: what is a healthy seedling, what is likely to survive, where do you get your seed, how long do you grow it for, when do you plant it?  We were able to have conversations around all of the elements that go into growing trees.

I remember clearly the “aha” moment where this young woman said, “We’ve been doing it wrong! We’ve always focused on growing as many seedlings as possible, and we haven’t worried about quality.”

See it live

Watch a video where Anthony talks about his work.

 

You can learn more about the reforestation programs that the University of Idaho nursery is involved with here.

Get more information on applied environmental research in our

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Dec 17

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Philippines Part 2: Overcoming Native Challenges with Remote Data

In one of the first agroforestry efforts in mountainous terrain, Moscow, Idaho community leader Loreca Stauber, Dr. Anthony S. Davis, Tom Alberg and Judi Beck Chair in Natural Resources at the University of Idaho, and their partners have initiated a program where U of I students travel overseas to work with farmers of Banguet province in the Philippines to develop the skills needed to grow high quality tree seedlings.  Local vegetable farmers have historically terraced the mountains that have been forested so they could grow monoculture crops, causing serious erosion (read about it here).  The land has degraded so much that the Philippine government has stepped in: warning farmers to begin conservation techniques, or they will take away the land and manage it themselves.

People building a local nursery in Benguet

Building a local nursery in Benguet.

Inspiring Students to Look at the Big Picture

One of the steps in helping local farmers to solve this problem is to create a local nursery where they can start growing native plants and trees.  Fortunately, the University of Idaho has operated a tree nursery for over one hundred years, and they understand how to grow trees. Dr. Davis specializes in setting up native nurseries for growing native plants all over the world. He says, “I want our students to be exposed to this because we’re graduating students who should be problem solvers, who should be able to look at the biggest challenges and contribute their own ideas towards resolving those challenges.”

Loreca Stauber adds, “We are part of the world and the world is part of us. The students can do more than just get their degree and find a job. Anthony and Kea, when they do this, inspire students to look at a bigger world than they are currently living in.”

Training Students to Understand Native Terrain and Resources

Davis says a good plan needs to take local conditions into account:  “The principles of growing trees are actually universal. It doesn’t matter whether you’re in Haiti, Lebanon, Idaho, or in the Philippines. Those principles are the same and they’re readily transferable. It’s how you adapt them to unique local situations that makes a difference.”

Close up on bamboo stalks

“It’s not really about the best way to grow a plant in a greenhouse environment; It’s about the best way to grow a plant that will also survive on its outplanting site.”

Kea Woodruff, former U of I Nursery Production and Logistics Associate, now at Harvard University, says they train the students who go overseas on the “target plant” concept:  designing a growing regime based on what the plant is going to need in its future home. She says, “It’s not really about the best way to grow a plant in a greenhouse environment; It’s about the best way to grow a plant that will also survive on its outplanting site. Determining what the outplanting site is and what each species will need to survive on that outplanting site is what determines greenhouse operations.”

Dr. Davis says you need to consider native resources when doing these types of projects.  “There could be plumbing there, but there’s no guarantee that when you turn the system on, the tap water will come out. That depends on the seasonality of the rains. It’s part of why we wanted the project partners (the farmers) to have data loggers: so we could look at the data together and get a better feel for when water is most abundant and when it’s most scarce, so it can be stored for later use.”

Overcoming Native Challenges with Remote Data

Decagon (now METER) donated data loggers to the program so that Dr. Davis and other people on the team could look at data with the farmers in the Philippines and advise them when to irrigate.  Davis says, “One of the things that’s most important in trying to set up a very remote nursery and manage the production in that nursery from approximately four flights, twelve hours, and twelve time zones away, is knowing what’s going on. There are things that are really easy to ask, like could you send me a picture every Wednesday and Saturday of the nursery, or could you measure the height and the diameter of the seedlings? What’s much harder to tell is how much water is coming in, or what the temperature was during the day or night, because those require people to be monitoring things at a greater frequency than is often possible. If we know how much water is coming into the nursery from rainfall, we can build collection systems so that we can manage where that water goes later on.”

Managing data for both the short and long term is critical, says Davis, because it’s often whether there was rainfall in the predicted amount, and at the right time, that determines whether a seedling establishes or not.

Next week:  The conclusion of our three part series: an interview with Dr. Davis and Kea Woodruff, discussing the cultural challenges of reforestation in different countries.

Acknowledgements:  The SEAGAA agroforestry project in Benguet is agro and forest; the farmers received a grant from the Rufford Foundation based in the UK to build a greenhouse and much of the water catchment system and auxiliary structure that go with a nursery facility.  They also received a sizable grant from the Philippine government to launch mushroom growing as a necessary complement to help support long-term agroforestry. The project is beyond reforestation – it is the growing of trees, shrubs, ground cover, the restoring of watersheds, creating livelihoods, the rebuilding of soil fertility and integrity, the revival of springs which have vanished with the removal of perennial flora, and the restoring biodiversity to bring back the natural checks and balances of a natural ecosystem.

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

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