Our primary interest at the farm, however, was the soil pit. The pit was located near the center of the farm, between two recently plowed fields and edging right up to the north side of a gravel road. The pit was approximately 15 to 20 feet wide and 8 feet deep, sporting a modest covering of briar and grass growth and a northern face that was greatly eroded and dangerously close to undermining and washing out the gravel road that lay adjacent to it. Erosion had also undermined a post that helped support the wire fencing surrounding the pit. This fencing was a safety feature used to keep animals and humans from falling into the pit and harming themselves. In order to maintain the soil pits continued functionality, all of these conditions would have to be cleaned up or corrected. This was what the maintenance task of our trip consisted of. Before we started this work, however, Dr. Noller was to explain several things to us about soil pits, the soils of this area, and what it was used for.
Dr. Noller began by explaining that this part of the Willamette Valley was part of the area whose soils had been enriched by the Missoula floods that occurred some 15,000 years ago. His story was not unlike the one explained in lecture. Multiple floods had filled the Willamette Valley perhaps 25 or more times over a several thousand year period, bringing with it sediment from as far away as present day Canada, Montana and Washington. This created a modern day bounty of agricultural land in the Willamette Valley. Doctor Noller stated that the soil on this site contains sediment deposited from the Missoula floods as deep as 12 meters. He also pointed out other geographical features located at the farm that were related to the floods called keel hull pits (see side notes for full detail). A third point he made regarding the soil in this area was that periodic flooding of the Willamette River caused erosion to occur in the area, meaning that at one time, the sediment deposited in this area could have been even greater than it is today.
Before we began cleaning up the site, Dr. Noller pulled out several books including the Munsell Color Chart, Keys to Soil Taxonomy, and the Field Guide to the Description of Soil Profiles (These and many other technical manuals on soils can be found at the following website sponsored by the federal agency the National Resource Conservation Service: http://soils.usda.gov/technical/ ). He showed us the steps someone would take to key out a soil sample from the site. The keying process starts out fairly simply. Matching a colored chart to the color of a piece of soil and deriving a number based off of hue ( primary shade), value (light to dark coloring), and chroma (brightness). From here, however, keying gets tricky. Knowing how to choose from soil order, suborder, great groups, subgroups, families, down to a series is much more complicated. To narrow down one of over 19,000 soil series in the United States alone takes an understanding of extensive terminology, history of an area, and in many cases, physical and chemical testing. As Doctor Noller read aloud the definitive requirements for categorizing soils from one level to the next, it became clear how important soil pits are for the classification process. Determining keying factors often includes information that can only be gathered from a perspective that includes a vertical display of all horizons. For example, suborders may require observing an argillic horizon (white clay), presence of a calcic horizon (lime), or the presence of glass; all of which require the ability to feel, see, and possibly subject to tests, sub-horizons of a given location. Soil pits are instrumental in both categorizing soil from a given area as well as developing large scale mapping of regions, countries, and even the entire pedosphere. Fortunately, information from soil pits has been being gathered and organized into databases for quite some time. NRCS, the Natural Resource Conservation Service, is the primary federal government source that aids in soil related information gathering and decision making. NRCS is a federal component that is part of the Department of Agriculture. GIS (Geographic information system) is a tool used for mapping and displaying data including soil types that is used by agency’s such as NRCS. Soil pit analysis across the nation has been, and still is, instrumental in developing this highly useful database. What about the future, though? Will a time come where some type of laser can be shot into the ground creating a worm sized hole that can be used to reveal all the secrets that lie in the soil below? Even if such technology comes into existence, soil pits will still be used by the more intrepid soil scientists. Being able to see, feel, and be immersed in the earth is something that people like Dr. Noller could not do without. This would be like a forester managing a forest from satellite images. Without that immersion into one’s work, what kind of bond will one develop with nature? Remember the quote from Baba Diouhm from our soils lecture, “In the end we will conserve only what we love. We will love only what we understand.”
The soil at Hyslop Farms is categorized in the Mollisol order. It is of the Woodburn series (named after the city of Woodburn) and it consists of a finely textured, light brown, silt loam soil that is rich in nutrients. It is a prairie or grassland soil that in most cases has been converted to agricultural use. Taxanomically it is defined as a fine-silty, mixed, suparactive, mesic aquultic argixeroll. It is a deep, light to dark brown soil that retains enough moisture and contains enough nutrients to proliferate excellent plant growth. Soils like this can be found in areas like the Willamette valley floor and slightly angled adjacent toe slopes. Precipitation in the areas where Woodburn soil develops is usually around 45 inches per year, allowing for moist conditions during much of the early growing seasons. Woodburn soils contain an A-horizon that is usually 9 to 17 inches thick and that classifies out as a 10YR/3/3 on the Munsell Color Chart. Plowed horizons (Ap) are slightly darker in color classifying out as a very dark brown at 10YR/2/2. Structurally, A-horizons are generally cloddy to very weak subangularly blocky. They are moderately sticky to plastic with a generous amount of root structures to help maintain a structure of fine to moderate pores. A-horizons contain a pH lvl of 5.9 (plowed) to 6.2 (unplowed) which makes them ideal for growing crops such as berries, orchards, grains, and grass crops. B-horizons in Woodburn soils are also deep and well developed being 17 to 54 inches deep and often consisting of several sub-horizons of similar but slightly more clayey textures. The B-horizons are usually a mix of medium to moderately coarse particles and medium to moderate subangular blocky structure. Root systems can easily penetrate into upper B horizons allowing for more aeration and infiltration of water. Thus, B horizons allow for moderate water infiltration while still retaining moisture through most of the year. C-horizons are also deep and well developed adding another 40 or more inches of depth to the soil. They are generally more clayey with some redox depletion.
Before we began cleaning up the site, Dr. Noller pulled out several books including the Munsell Color Chart, Keys to Soil Taxonomy, and the Field Guide to the Description of Soil Profiles (These and many other technical manuals on soils can be found at the following website sponsored by the federal agency the National Resource Conservation Service: http://soils.usda.gov/technical/ ). He showed us the steps someone would take to key out a soil sample from the site. The keying process starts out fairly simply. Matching a colored chart to the color of a piece of soil and deriving a number based off of hue ( primary shade), value (light to dark coloring), and chroma (brightness). From here, however, keying gets tricky. Knowing how to choose from soil order, suborder, great groups, subgroups, families, down to a series is much more complicated. To narrow down one of over 19,000 soil series in the United States alone takes an understanding of extensive terminology, history of an area, and in many cases, physical and chemical testing. As Doctor Noller read aloud the definitive requirements for categorizing soils from one level to the next, it became clear how important soil pits are for the classification process. Determining keying factors often includes information that can only be gathered from a perspective that includes a vertical display of all horizons. For example, suborders may require observing an argillic horizon (white clay), presence of a calcic horizon (lime), or the presence of glass; all of which require the ability to feel, see, and possibly subject to tests, sub-horizons of a given location. Soil pits are instrumental in both categorizing soil from a given area as well as developing large scale mapping of regions, countries, and even the entire pedosphere. Fortunately, information from soil pits has been being gathered and organized into databases for quite some time. NRCS, the Natural Resource Conservation Service, is the primary federal government source that aids in soil related information gathering and decision making. NRCS is a federal component that is part of the Department of Agriculture. GIS (Geographic information system) is a tool used for mapping and displaying data including soil types that is used by agency’s such as NRCS. Soil pit analysis across the nation has been, and still is, instrumental in developing this highly useful database. What about the future, though? Will a time come where some type of laser can be shot into the ground creating a worm sized hole that can be used to reveal all the secrets that lie in the soil below? Even if such technology comes into existence, soil pits will still be used by the more intrepid soil scientists. Being able to see, feel, and be immersed in the earth is something that people like Dr. Noller could not do without. This would be like a forester managing a forest from satellite images. Without that immersion into one’s work, what kind of bond will one develop with nature? Remember the quote from Baba Diouhm from our soils lecture, “In the end we will conserve only what we love. We will love only what we understand.”
The soil pit at Hyslop farms has been used for the last ten years by Dr. Noller primarily as a learning tool. Having a wall of soil looming up in front of you gives one a more immersed perspective than does just looking at a picture in a book. Being able to have a three dimensional vertical image that you can touch, smell, and even listen to (when you are shoveling into the soil for example) helps to extract that much more information from a soil sample as well as to differentiate between soil types that appear similar by just our visual sense. We experienced many of these sensations in our primary maintenance mission which was to build a terrace system along the southern side of the pit which was eroding and undermining the road. Dr. Noller explained how terraced systems had been used by man nearly since the time agriculture began. Terrace systems are instrumental in limiting erosion and surface runoff, holding in moisture content or controlling water levels, and in maintaining a desired form in the landscape. Almost every known civilization in history has used terrace systems in agriculture including the Incas, Babylonians, Greeks, Romans, and Egyptians. Even to this day you can go to an NRCS website to learn how to build terrace systems (http://www.ks.nrcs.usda.gov/news/coneds06/TerraceSystems06.html ).
At the soil pit, we too were building a terrace system, in order to attempt to reduce or eliminate the erosion of the southern wall of the soil pit. Our terrace system involved digging into the base of the pit along the southern side and placing a row of turned up concrete blocks. We then dug out another row above this one in the same wall and placed another row of concrete bricks. We continued to build walls of concrete blocks higher and more deeply embedded into the southern wall as we went up. At the same time we also worked on clearing brush and debris from both the pit and the path leading down into it on its western side. The fence post that was about to fall into the pit due to erosion was moved back and pounded into more solid soil.
Benton County, Oregon (OR003)
Unit Name Acres in AOI Percent of AOI
8 Amity silt loam, 0 to 3 percent slopes 129.3 5.8%
12 Awbrig silty clay loam, 0 to 2 percent slopes 135.8 6.1%
14 Bashaw clay, flooded, 0 to 3 percent slopes 367.7 16.5%
15 Bashaw clay, nonflooded, 0 to 3 percent slopes 44.6 2.0%
16 Bashaw silty clay loam, nonflooded, 0 to 3 percent slopes 45.4 2.0%
36 Chehalem silty clay loam, 0 to 3 percent slopes 12.3 0.5%
51 Concord silt loam, 0 to 2 percent slopes 13.8 0.6%
52 Conser silty clay loam, 0 to 3 percent slopes 32.6 1.5%
53 Dayton silt loam, 0 to 2 percent slopes 40.9 1.8%
60 Dixonville-Gellatly-Witham complex, 2 to 12 percent slope 14.0 0.6%
91 Jory silty clay loam, basalt bedrock, 2 to 12 percent slopes 1.6 0.1%
113 McAlpin silty clay loam, 0 to 3 percent slopes 8.5 0.4%
118 McBee silty clay loam, 0 to 3 percent slopes 21.5 1.0%
119 McBee silty clay loam, nonflooded, 0 to 3 percent slope 16.5 0.7%
130 Pengra silt loam, 2 to 12 percent slopes 12.4 0.6%
139 Salem gravelly silt loam, 0 to 3 percent slopes 34.1 1.5%
140 Santiam silt loam, 2 to 8 percent slopes 36.1 1.6%
141 Santiam silt loam, 8 to 20 percent slopes 90.4 4.1%
155 Waldo silty clay loam, 0 to 3 percent slopes 137.7 6.2%
163 Willakenzie loam, 2 to 12 percent slopes 61.6 2.8%
164 Willakenzie loam, 12 to 20 percent slopes 11.2 0.5%
169 Willamette silt loam, 0 to 3 percent slopes 136.7 6.1%
170 Willamette silt loam, 3 to 12 percent slopes 259.1 11.6%
171 Willamette silt loam, 12 to 20 percent slopes 10.2 0.5%
177 Woodburn silt loam, 0 to 3 percent slopes 473.5 21.2%
178 Woodburn silt loam, 3 to 12 percent slopes 82.0 3.7%
Totals for Area of Interest 2,229.5 100.0%
Pit of Mystery
As we were driving through the Hyslop farm there was a number of divots in the field that appeared to be dried up ponds. Dr.Noller then drove us into one of these peculiar depressions and proceeded to stop the van. He then began to ask us if we knew what we were parked in. With the mention of the Missoula floods only once or twice in lecture, we were still fresh on the topic. We were unable to answer Dr.Noller’s question so he proceeded to explain to us that the van was parked in the ancient “keel hole” of an iceberg. These historical landmarks are thought to have been made from giant pieces of ice sitting on the valley floor creating divots in the earth from such force and weight. The link below describes the news paper article featuring Dr.Noller. The video shows some of the keel holes at the hyslop farm and the use of LiDar to map out the field.
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