soil

What Can a Hurricane Tell Us AG��˰ټ��ֹٷ��վ Soil Health Metrics?

gentes — Wed, 26 Aug 2020 14:14:53 +0000

What Can a Hurricane Tell Us AG��˰ټ��ֹٷ��վ Soil Health Metrics?

August 26, 2020

gentes Wed, 08/26/2020 - 08:14

Soil scientists use a variety of metrics to measure aspects of soil health. For example, they may measure the percentage of soil organic matter (SOM) or look more specifically at available carbon or nutrients. But how well do these metrics hold up under extreme conditions—say, in the aftermath of a hurricane?

Dr. Zachary Kayler, an assistant professor in the Department of Soil and Water Systems at the University of Idaho, recognized an opportunity to test the sensitivity of soil health metrics using soil samples taken before and after Hurricane Maria, the destructive Category 5 hurricane that tore through the Gulf of Mexico in late 2017. He used soil samples from the NEON Archival Samples Catalog to test the ability of a widely-used soil health metric to detect changes from an extreme weather event.

How Soil Health is Measured

Soil is made up of both organic and inorganic elements. Organic material is the part of the soil made up of living or formerly living things, such as microbes, fungi, and decaying plant and animal tissues. Organic matter contains carbon (C) along with other elements necessary for microbes, fungi, and plants to thrive, such as nitrogen (N) and phosphorus (P).

The content of organic material in a soil sample tells us a lot about the health of the soil and the ecosystem as a whole. Soils rich with organic material are able to support more plant and animal life. Soil health metrics are critically important for farmers and agricultural planners as well as ecologists and land managers. Monitoring soil health tells us how soil is responding to agricultural regimens, land management decisions, changes in climate, and natural disturbances.

There are several different metrics used to measure soil health. The simplest is the total amount of carbon-containing material as a percentage of soil weight. Other metrics look more specifically at the bioavailability of carbon or nutrients—that is, whether the elements are in a form that living things can readily use.

Zachary’s study looks specifically at a soil health metric called permanganate oxidizable carbon, or POX-C. POX-C measures the fraction of SOM that is in a form that oxidizes in the presence of potassium permanganate. This is also the form of carbon most readily degradable by soil microorganisms. The POX-C measurement is widely accessible and cost effective for scientists, making it one of the most widely used and accepted methods for measuring the amount of bioavailable carbon in soil. Zachary wanted to find out how sensitive POX-C is to changes in soil composition caused by an extreme weather event, as well as compare it to other soil health indicators.

Technician John Hayes preparing a soil sample for the elemental analyzer. Photo credit: Zachary Kaylar.

He says, “Different measurement methods give us different perspectives on soil health. Many of these methods haven’t changed much over the last 100 years. Now, we’re seeing dramatic changes in weather events, climate patterns, and land use pressures. It’s important to understand how our available tests perform under conditions that may be very different than when they were developed, so we know how well indices developed in the past will continue to perform in the future. One way to get a glimpse of that is to see how they perform during an unusual event.��

Putting Soil Health Metrics to the Test

Hurricane Maria, which struck the island of Puerto Rico in September 2017, provided an opportunity for Zachary to do this research. Maria was one of the most devastating storms to ever hit Puerto Rico, directly causing hundreds of deaths and widespread and long-lasting damage to infrastructure, businesses and residences across the island.

Maria also had a big impact on natural ecosystems. The NEON field sites in Puerto Rico sustained significant damage. Data from the Puerto Rico field sites provides a window into ecosystems before and after the hurricane, allowing scientists to see how Maria impacted vegetation structure, community composition, and other measures of ecosystem function, health, and resilience. The Guánica Forest (GUAN) field site is in a dry tropical coastal forest located in Guánica Forest Reserve. Lajas Experimental Station (LAJA) is an agricultural research station used for cattle grazing and crop growing. Data from these sites allow researchers to see how both natural and human-impacted ecosystems respond to natural disturbances.

Zachary used soil samples taken from the GUAN and LAJA sites before and after the hurricane, which are available from the NEON Archival Sample Catalog. His primary interest was in testing the ability of the POX-C soil health metric to provide meaningful information following an extreme event. “We need to know whether soil health metrics are still valid and reliable during abnormal events like droughts or severe storms,�� he explains. “Our metrics are generally just tested under normal conditions. If all of the points that we look at are within the mean, we don’t know whether the metric is still giving us good information for conditions outside the mean. Is it still valid? Does it mean anything? Sometimes, we ignore these ‘long-tail�� events, and we shouldn’t.��

Some of Zachary’s previous experiments have involved inducing or simulating extreme conditions such as drought, flooding, or snow insulation. But capturing a real extreme event in nature is much more difficult.

The soil archives from GUAN and LAJA provided a rare opportunity to see how well POX-C captures changes in carbon availability after a hurricane. “We can’t predict exactly when and where a hurricane will hit, so it’s rare to have soil samples available from both before and after a hurricane,�� Zachary says. “That’s why long-term monitoring programs like the NEON program are so important. They provide consistent, comparable data over time. When a natural event like this hits, we are able to look at the before and after data to see the effects.��

Finding the Right Metrics to Measure Ecosystem Recovery

The incubations of soil samples collected before and after Hurricane Maria show decreases in carbon and nitrogen availability in both the forested and agricultural sites. While Zachary’s study does not attempt to explore the reasons behind these changes, the results align with his expectations.

He explains, “Disturbances like this cause reorganization for all of the ecosystem players involved, including vegetation and microbes. After an event like this, communities are trying to reestablish themselves. Plants are drawing on carbon reserves during regrowth and microbial communities are being actively drawn into collecting nutrients used by the plants. A lot of the vegetation has been removed, so more leaching can occur during precipitation. A lot more work needs to be done to really understand all of these interactions. It is important to know that soil health metrics, especially incubations, are providing accurate information so that we can get a clearer picture of ecosystem health and recovery after a large disturbance event.��

The study compares POX-C analysis to other measures of soil health and carbon availability, including elemental analysis (which involves combusting soil samples) and incubation (which measures C and N loss to microbial processes during an incubation period). The results show that incubation provides a better measure of the hurricane’s impact on soil health than POX-C or elemental analysis. The POX-C measurements show little change before and after the hurricane. Zachary says, “Soil incubation is really the gold standard, and this study showed that it was the most sensitive to changes due to the disturbance. POX-C was able to reliably detect differences in available carbon between land use types—the forested site vs. the agricultural site—but did not detect changes before and after the hurricane.��

Zachary Kaylar in Puerto Rico (Domain 04). Photo credit: Zachary Kaylar.

Selecting the right measurement tools to measure the impact of natural disturbances and monitor ecosystem recovery is important. If the tools used are not sensitive enough or do not provide the right information, researchers may miss important clues that could guide better restoration or land management decisions. Zachary hopes to have opportunities to repeat the study in different regions to see if the results vary for different soil types and climate zones.

“We need to take care of our soils if we want them to be sustainable for the future,�� he says. “It’s important to understand the limits of our current testing methods so we can better monitor soil health and make effective decisions. We may need a combination of methods, or new methods entirely, to get an overall picture of soil health, especially as climates and ecosystems change.��

Case Study

Digging Up the Dirt on Soil Organic Matter

lgoldman — Fri, 06 Sep 2019 20:49:48 +0000

Digging Up the Dirt on Soil Organic Matter

September 6, 2019

lgoldman Fri, 09/06/2019 - 14:49

How are ecosystems across the continent changing over time? What are the relationships between ecosystem composition and soil organic matter? And how are soil composition and carbon storage potential likely to change in the future? The answers lie under our feet.

Adrian Gallo, a Graduate Research Assistant in the Oregon State University Department of Crops and Soil Sciences, is investigating soil organic matter as part of a study funded by the National Science Foundation (NSF). The study, "A continental-scale assessment of the linkages between soil organic matter stabilization mechanisms, controls, and vulnerability," is digging up answers that could help rewrite the book on soil.

Soil Organic Matter: An Underground Record of Ecosystem Composition

Soil is a complex mixture of mineral particles, nutrients, air, water, living organisms and organic matter. Soil organic matter (SOM) is the fraction of the soil made up of plant or animal tissues in various stages of decomposition, animal waste products, and living and non-living microbial biomass. When plants and animals die in a terrestrial environment, their tissues are broken down by microbes into carbon-based molecules that are utilized by living plants as they grow. SOM is an important measure of soil fertility; productive agricultural soils contain 3% - 6% SOM.

The amount and type of SOM in the soil are directly related to the composition of the vegetation that lives and dies in the immediate area. The majority of SOM comes from the dominant plants growing in the ecosystem. Some of the organic material comes from the stems, leaves or needles that grow above ground and gradually become buried as they die and decompose. The remainder comes from the roots that decompose in place when the plant dies. The resulting carbon compounds in the soil can be thought of as "shoot carbon" and "root carbon."

Root carbon and shoot carbon each have a slightly different chemical structure. Carbon compounds from different types of plants—e.g., grasses vs. conifers vs. deciduous trees—also have their own chemical signatures, or biomarkers. The structure of the carbon-based molecules acts like a fingerprint to identify the types of plants that decomposed to form the SOM, and whether the carbon compounds came from the roots or the shoots of the plant.

Analyzing these biomarkers can tell us a lot about how the composition of the ecosystem has changed over time. As you dig deeper into the soil, you are going back in history. A deep soil core provides a geologic record of SOM composition that can go back as far as 20,000 years into the past. By looking at the structure of the carbon molecules at different depths, we can get an idea of the types of plants that were present in the ecosystem at different points of time.

Creating a Continental-Scale Carbon Compound Inventory

Adrian and his team are using soil samples from the NEON program to create an inventory of SOM that spans the continent.

The samples come from 42 of NEON’s 47 terrestrial field sites. During the construction of NEON’s field sites, boreholes were made at each site for installation of soil carbon (CO₂) sensors. The resulting soil cores, which average 1 m. deep, were shipped to the Oregon State University for analysis under the NSF grant.

"Working with the NEON project solved one of the biggest logistical challenges for a project of this scale, which was 'how do you get the soil?'" says Adrian. "Instead of physically traveling to locations across the continent and systematically gathering soil, we can use the soil cores already produced by NEON." The NEON project uses strict protocols for gathering soil samples, ensuring that the soil cores would be collected using the same methods at each location for quality and comparability.

Using data from the NEON project had another advantage, too. NEON field sites are strategically located within 20 ecoclimatic zones (or NEON domains) across the country, from tropical Puerto Rico to the Alaskan Arctic Tundra to the Hawaiian Islands. Soil cores from the 42 NEON terrestrial field sites represent ecosystems from all of the biomes in North America.

Adrian and his team analyzed the soil cores using gas chromatography-mass spectrometry (GC-MS), an analytical method that allows them to separate and identify the different carbon compounds found in the sample and determine the relative quantity of each. The resulting data show the types and relative quantities of different carbon compounds at different horizons (layers) of the soil cores from each site. This allows researchers to correlate SOM composition with vegetation types and abundance at each site.

They now have a continental-scale inventory of SOM composition in different biomes across North America. In addition to enabling researchers to answer important questions about the relationships between current ecosystem structure and soil organic matter composition and stability, the data set will provide a baseline for further research into ecosystem change and carbon dynamics.

Rewriting the Book on Soil Carbon Cycling

The NSF study, of which Adrian's research is one part, is gathering evidence that could change our understanding of how carbon cycles in soil. This, in turn, could improve our climate models.

Soil is the most important terrestrial carbon sink. A carbon sink is a part of the natural environment that stores carbon and keeps it out of the atmosphere. An estimated 2500 gigatons of carbon are held in soil globally, dwarfing the amounts of carbon currently in the atmosphere or residing in terrestrial organisms. Understanding SOM, which represents the organically-derived portion of carbon in the soil, is critical to our understanding of the carbon cycle.

Carbon continuously cycles between the soil, living things and the atmosphere. This cycle is heavily influenced by factors such as soil moisture, temperature and microbial activity. As temperatures warm and precipitation patterns change, this will impact the carbon storage potential of the soil. Part of the goal of this study is to better understand how climate change may impact carbon storage potential and stability in different soil types and ecosystems.

Unlike carbon cycling in rocks and oceans, which operate on geologic timescales, the carbon pool held by soil is cycling on human timescales. Better models may lead to improved soil management practices that could increase carbon uptake potential.

"What we are finding in the field of soil science research is that we know a lot less than we thought we did," Adrian explains. "We were using essentially the same analytical methods for more than 100 years, and our predictions and models were built using that data. It's only in the last 25 years that we have had instruments sensitive enough to test some of these predictions, and in some cases we've found that our models are completely wrong. This research will help us reevaluate those old paradigms and build better models of how carbon cycles in soils."

As a next step, Adrian hopes to see other researchers examine the microbial side of the equation. Half of each soil core was frozen before Adrian's team began their analysis. These frozen soil samples are waiting for a microbiologist to analyze them for microbial activity and community composition. Combining analysis of the living communities within the soil with Adrian's abiotic analysis would provide important insights into the impact of microbial activity on SOM and carbon cycling.

In the meantime, Adrian and his team are continuing work on their continental carbon compound inventory. They have requested soil samples from "megapits" dug at each NEON terrestrial field site. The megapits collect soil at each soil horizon down to a depth of 2 m or more at most sites. Analyzing these deeper layers will provide a look further back into the ecological history of each site.

"The questions we're looking at really are the perfect melding of biology, chemistry, physics and geology," Adrian says. "This study has the potential to completely change our understanding of soil carbon cycling and how all of these processes work together."

Case Study

Calibrating Soil Sensors? It's a Dirty Job, But We Had To Do It

lgoldman — Fri, 20 Jul 2018 17:47:37 +0000

Calibrating Soil Sensors? It's a Dirty Job, But We Had To Do It

July 20, 2018

lgoldman Fri, 07/20/2018 - 11:47

Accurately determining soil moisture can sometimes be tricky because differences in soil composition and structure can lead to lower accuracy of sensor-based measurements. To ensure data quality and consistency across 47 field sites, scientists had to carefully calibrate soil moisture sensors for each unique soil profile. Here's what they did—and why it matters to the NEON community.

Moisture Matters: Why We Measure Soil Moisture Levels

The amount of moisture in the soil is one of the critical variables that influence the overall makeup and diversity of the local ecosystem. The type and abundance of vegetation an ecosystem can support depends heavily on soil moisture patterns. So do fungal and bacterial communities living within the soil and, ultimately, all of the animal populations in the ecosystem. Studying soil moisture also provides insight into hydrological and biogeochemical processes.

Monitoring trends in soil moisture levels across NEON’s terrestrial sites provides data that will help ecologists investigate a broad range of questions, such as:

How are soil moisture levels changing over time in response to climate change?
How is soil moisture interrelated with other key indicators, such as temperature?
How are changes in land use affecting the ability of the soil to retain moisture?
How does soil type influence moisture retention?
How do soil moisture levels impact the spread of pathogens or invasive species?
How are changes in precipitation patterns likely to impact vegetation growth and agricultural yield in different regions?

Answering these and other questions about soil moisture will help scientists build better models to forecast how changes in climate and land use will impact soil moisture patterns and, in turn, many of the processes and organisms that depend on them.

Getting Accurate Measurements for Different Soil Types

There are several different ways to measure soil moisture, each with their own pros and cons. For the NEON project, scientists needed a sensor that could gather accurate and precise data at different depths in a variety of soil types. The sensors would need to be able to collect and transmit data automatically while being left in the field for long periods of time. Under National Science Foundation (NSF) guidelines, they would also need to have the ability to be periodically removed from the field and recalibrated with minimal impact to the surrounding soil.

Based on these requirements, scientists working on the design of the NEON project selected a capacitance-based sensor. These sensors are placed in borehole tubes within the soil and, unlike other sensor types, are not buried directly in the soil. This makes them easy to place and easy to remove for recalibration. The sensors send an electromagnetic signal into the surrounding soil and measure the signal that is reflected back from the soil. This reflected signal provides a measure of the dielectric potential of the soil (the ability of the soil to transmit electricity). Because the magnitudes of dielectric constants of water and dry soil are notably different, measuring the dielectric potential within a volume of soil can provide information about water content.

Previous researchers found that the measurements taken by capacitance sensors are sensitive to variations in soil type. As a result, sensors must be calibrated to each soil type in order to reduce measurement uncertainty and ensure that data are accurate and comparable.

For the NEON project, researchers need to be able to compare data taken across terrestrial field sites in 20 different climate domains, each containing many different combinations of soil types differentiated by chemical composition, physical structure, density, porosity, particle size, pore size and other variables. Before collecting soil moisture data, project scientists needed to find a unique set of calibration coefficients for each site’s soil types.

That's a Whole Lot of Dirt!

Calibrating the soil sensors is a massive (and very dirty) undertaking. Soil collections started in June of 2012 and are still ongoing today.

Staff scientists collect blocks of soil from each site using giant "cookie cutters" (40 cm x 40 cm x 16 cm deep). Up to six soil samples were taken from each NEON field site to ensure good representation across all soil horizons (visibly distinct layers of the soil).

Each soil block was then sent to a lab. To calibrate the sensors, researchers gradually immersed each soil block in a tub of water. The soil block was then allowed to drain under gravity through perforations in the bottom plate until the water was no longer actively dripping out of the bottom plate. This represented the field capacity of the soil, or the amount of water remaining after the rate of downward movement has ceased. A capacitance soil sensor was then placed into a borehole within the block and left there to continuously measure the changing moisture levels as the block dried. The blocks were left to dry until moisture levels approached permanent wilting point, a process called a "dry down." Researchers used raw frequency measurements taken throughout the dry down to calibrate the sensors to each unique soil type. The entire process can take up to six months depending on the soil type under calibration.

Soil block calibration in a NEON laboratory

Full details of the entire process (collections and calibrations) can be found in a paper published in the Vadose Zone Journal: A Robust Calibration Method for Continental-Scale Soil Water Content Measurements. It represents one of the largest known (quite possibly the largest) soil calibration studies in North America.

Soil-specific calibrations are now complete for 222 blocks from 40 NEON field sites. Soil moisture data from these sites are also available on the NEON Data Portal. Calibrations for the remaining sites are expected to be complete by the end of 2018.

Monitoring Soil Moisture Trends on a Continental Scale

The NEON project is the first to provide standardized soil moisture data on a continental scale in North America. Carefully calibrating the capacitance-type sensors to each soil type within each NEON field site allows for accurate (< 3.5% error) monitoring of soil moisture, making it usable for a broad range of ecological research, modeling and forecasting projects.

The ability to compare soil moisture data between sites and across the continent will enable ecologists to investigate large-scale ecological questions, such as how soil moisture levels impact the carbon storage potential of an ecosystem. Other potential uses include looking at habitat traits that are favored by rodents that are implicated in the spread of Hantavirus or examining how soil moisture, temperature and other factors impact seed germination after a forest fire. A better understanding of how soil moisture is interrelated with other ecological variables could enable better land management planning, agricultural forecasting and climate change modeling.

Soil moisture data are freely available via the NEON Data Portal. Researchers can also request archival samples of soil collected at the NEON field sites.

NEON purchases soil coring machine for more efficient soil sensor installation

Anonymous — Fri, 13 Feb 2015 21:45:43 +0000

NEON purchases soil coring machine for more efficient soil sensor installation

February 17, 2015

Anonymous (not verified) Fri, 02/13/2015 - 14:45

In an effort to provide standardized and more efficient ways to install soil sensors, NEON recently purchased the first of several soil coring machines that will be used to create boreholes which will be used to install soil sensors up to three meters deep at all 60 terrestrial sites around the US.

Specifically, the machines will hasten the installation of multiple soil temperature, soil moisture and CO₂ concentration sensors at each site. A total of at least 1500 boreholes will be constructed. Using a machine to produce the boreholes is much faster than auguring them by hand and will help ensure that the boreholes are constructed consistently across all 60 sites, regardless of soil type.

In order to generate high quality soil data it is essential the soil surrounding each sensor is only minimally disturbed. To achieve this, the sensor installation crew will be performing extensive testing with the new coring machine to determine the optimal installation strategy to ensure minimal disturbance.

This is the first of several soil coring machines that NEON will purchase and deploy around the country.

Soils and Sediments

Anonymous — Thu, 31 Jul 2014 19:38:03 +0000

Soils and Sediments Anonymous (not verified) Thu, 07/31/2014 - 13:38

NEON collects a variety of soil measurements and samples at all terrestrial field sites for physical and biogeochemical analyses, and one-time soil characterization. At aquatic sites, physical data of sediments are also collected.

Soil Core Sampling Methods

Every five years, field technicians collect soil cores from plots at terrestrial sites. Each plot is split into quadrants: three soil cores 30 cm deep and 0.5 m apart are collected from each quadrant and combined as a single soil composite representative of that quadrant.

Initial Soil Characterization

During site construction of all terrestrial field sites, NEON collects soil from each horizon at a single, temporary soil pit at terrestrial field sites, called the "megapit". Megapit soil samples characterize the soil conditions at the time of site construction. The pit is located in the locally dominant soil type, near the instrumented meteorological tower (or flux tower), and is selected to be representative of the soil sensor locations. In addition to the megapit, NEON collects soil pit samples from a number of 1 meter deep pits distributed throughout the site for a one-time characterization of soil properties. NEON works with the U.S. Department of Agriculture (USDA), Natural Resources Conservation Service Kellogg Soil Survey Laboratory to perform a suite of chemical and physical analyses on each soil sample. Results of these analyses and other relevant information are documented in the sample data. The list of laboratory analyses performed and associated data are available upon request.

Megapit Soil Sample Archiving Methods

Before NEON deposits samples in the Soil Archive, soil are air-dried, mineral soil are sieved (2 mm) and organic soil are broken up and mixed by hand in the laboratory. NEON archives a total of 1.2 to 3.6 kilograms of soil from each horizon. The total sample is split between at least four amber glass jars that are stored in locked, water-resistant and fire-resistant cabinets at ambient room temperature. After collection, megapit soil samples are stored in the NEON Soil Archive and available upon request to support community research. Surface soil samples are also available.

Megapit Soil Sample Analysis Methods

NEON works with the U.S. Department of Agriculture, Natural Resources Conservation Service Kellogg Soil Survey Laboratory, to perform a suite of chemical and physical analyses on each soil sample. Results of these analyses and other relevant information are documented in the soil sampling data. The list of laboratory analyses performed and associated data are available upon request. NEON also uses information collected from pits to calibrate soil and carbon dioxide (CO₂) and moisture sensors installed in plots across NEON terrestrial sites.

An Integrated Sampling Design

Soil sampling at NEON terrestrial field sites occurs in close proximity to organismal sampling and within the airshed of the instrumented towers to establish connectivity with atmospheric and aboveground organismal measurements. Biotic and abiotic elements of soil affect the movement and availability of water and elements across ecosystems, determine the availability of nutrients to vegetation and organisms, and play a central role in the global carbon cycle.

Related Soil Sensor Measurements

Automated soil sensors measure physical, chemical and biological properties at the soil surface and in the underground environment. The following measurements are collected at multiple depths:

Soil moisture
Soil temperature
CO₂concentration

The following measurements are collected at the soil surface

Photosynthetically Active Radiation (PAR) at soil surface
Soil heat flux
Solar radiation
Throughfall

Key Soil Sampling within Distributed Sampling Plots

Soil samples and associated analyses characterize the following:

Soil microbial communities, metagenomes
Soil texture, bulk density and organic horizon mass for initial characterization; repeated measurements of soil temperature and moisture
Biogeochemical analyses including pH, cations, anions, total carbon (C), nitrogen (N), phosphorous (P) and sulfur (S), fractions C and P, select soil N transformations (i.e., net N mineralization and net nitrification)
Coarse and fine root biomass and total carbon (C) and nitrogen (N) concentrations in fine root biomass

Sampling Sediments for Physical Properties

At aquatic sites, sediment samples are collected from 2 stations at each site: at wadeable streams and non-wadeable river sites, the aquatic sampling reach is divided in half longitudinally and sediment is collected throughout each half. In lakes, there are also 2 stations, the first near the buoy (the deep center point in the basin), and the second near the inlet infrastructure (about 1-2 m deep). Within each station, sediment samples are collected and homogenized from 5-10 deposition zones from both stations two times per year during the spring and fall aquatic biological sampling bouts. Samples are distributed into separate containers (one per analysis type: inorganic, organic, metals and sediment size) and shipped to an external lab for a suite of analyses that also include biogeochemical properties.

Data Products

Sediment physical properties (NEON.DP1.20197)

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soil

What Can a Hurricane Tell Us AG���˰ټ��ֹٷ���վ Soil Health Metrics?

How Soil Health is Measured

Putting Soil Health Metrics to the Test

Finding the Right Metrics to Measure Ecosystem Recovery

Digging Up the Dirt on Soil Organic Matter

Soil Organic Matter: An Underground Record of Ecosystem Composition

Creating a Continental-Scale Carbon Compound Inventory

Rewriting the Book on Soil Carbon Cycling

Calibrating Soil Sensors? It's a Dirty Job, But We Had To Do It

Moisture Matters: Why We Measure Soil Moisture Levels

Getting Accurate Measurements for Different Soil Types

That's a Whole Lot of Dirt!

Monitoring Soil Moisture Trends on a Continental Scale

NEON purchases soil coring machine for more efficient soil sensor installation

Soils and Sediments

Soil Core Sampling Methods

Initial Soil Characterization

Megapit Soil Sample Archiving Methods

Megapit Soil Sample Analysis Methods

An Integrated Sampling Design

Related Soil Sensor Measurements

Key Soil Sampling within Distributed Sampling Plots

Sampling Sediments for Physical Properties

Data Products

What Can a Hurricane Tell Us AG��˰ټ��ֹٷ��վ Soil Health Metrics?