Benton County, Oregon
170—Willamette silt loam, 3 to 12 percent slopes
Map Unit Setting
• Elevation: 150 to 400 feet
• Mean annual precipitation: 40 to 50 inches
• Mean annual air temperature: 50 to 54 degrees F
• Frost-free period: 165 to 210 days
Map Unit Composition
• Willamette and similar soils: 94 percent
• Minor components: 2 percent
Description of Willamette
Setting
• Landform: Terraces
• Parent material: Silty glaciolacustrine deposits
Properties and qualities
• Slope: 3 to 12 percent
• Depth to restrictive feature: More than 80 inches
• Drainage class: Well drained
• Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 1.98 in/hr)
• Depth to water table: More than 80 inches
• Frequency of flooding: None
• Frequency of ponding: None
• Available water capacity: Very high (about 12.2 inches)
Interpretive groups
• Land capability classification (irrigated): 2e
• Land capability (nonirrigated): 2e
Typical profile
• 0 to 6 inches: Silt loam
• 6 to 13 inches: Silt loam
• 13 to 24 inches: Silt loam
• 24 to 33 inches: Silty clay loam
• 33 to 45 inches: Silty clay loam
• 45 to 53 inches: Silty clay loam
• 53 to 60 inches: Silty clay loam
Minor Components
Dayton
• Percent of map unit: 2 percent
Landform: Terraces
177—Woodburn silt loam, 0 to 3 percent slopes
Map Unit Setting
• Elevation: 150 to 400 feet
• Mean annual precipitation: 40 to 50 inches
• Mean annual air temperature: 50 to 54 degrees F
• Frost-free period: 165 to 210 days
Map Unit Composition
• Woodburn and similar soils: 92 percent
• Minor components: 3 percent
Description of Woodburn
Setting
• Landform: Terraces
• Parent material: Silty glaciolacustrine deposits
Properties and qualities
• Slope: 0 to 3 percent
• Depth to restrictive feature: More than 80 inches
• Drainage class: Moderately well drained
• Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 1.98 in/hr)
• Depth to water table: About 25 to 32 inches
• Frequency of flooding: None
• Frequency of ponding: None
• Available water capacity: Very high (about 12.2 inches)
Interpretive groups
• Land capability classification (irrigated): 2w
• Land capability (nonirrigated): 2w
Typical profile
• 0 to 9 inches: Silt loam
• 9 to 17 inches: Silt loam
• 17 to 25 inches: Silty clay loam
• 25 to 32 inches: Silty clay loam
• 32 to 39 inches: Silt loam
• 39 to 54 inches: Silt loam
• 54 to 68 inches: Silt loam
• 68 to 80 inches: Stratified fine sandy loam to silt loam
• 80 to 92 inches: Stratified fine sandy loam to silt loam
Minor Components
Dayton
• Percent of map unit: 2 percent
• Landform: Terraces
Huberly
• Percent of map unit: 1 percent
Landform: Terraces
The farmer agreed to allow the crop and soil science department to retrieve and conduct studies on the red clover, one such as our own project. Below you can find photos of our group obtaining field samples of the red clover:
On October 16, 2011 our group retrieved the red clover samples with Dr. Sujaya Rao from the local farm's 20 different plots. The following month on November 21, 2011 our group met in the laboratory at Cordley Hall to investigate the clover crown borer more thoroughly.
Group members used scalpels, tweezers, and microscopes to take a look inside of the red clover roots. It's inside the red clover's roots that the clover crown borers inhabit for the majority of their lifecycle. We found anywhere between 6 and 15 clover crown borers living inside 4 different red clover samples. Below you can find photos of our group dissecting the red clovers and looking for clover crown borers inside the roots:
The red clover’s biggest impact on soil is being a natural source of nitrogen. This is done through a process where the red clover pulls nitrogen in from the atmosphere and transports it back into the soil. It is used around the world as a soil amendment on farmland. Farmers use the red clover as a rotational crop to fix nitrogen back into the soil. This practice was widely used before synthetic nitrogen was made available. It is also used for hay, silage, and grazing. Due to its short life, red clover fell out of favor with farmers steadily since the turn of the century.
One of the most threatening pests to the red clover is the clover crown borer. This pest is a small wood beetle that bores into the roots of the clover and destroys the plant from within. This pest is the reason red clover can be in only one location for three years at a time. Once the crop has reached three years duration the beetle population has grown to such a number that it begins destroying the crop.
Research is currently being done in order to amend this problem through better soil management techniques. Since MSG was banned there has been no viable method to control the beetles with pesticides. The pesticides being used currently are ineffective due to these beetles living the majority of their lives in the root of the clover plant below the surface of the soil. MSG was made specifically to penetrate soil and eradicate all pests above and below the surface of the soil. Modern pesticides do not penetrate the surface of the soil or get taken into the plant being considered useless against the beetle. Research into better controlling this pest is still in its infancy, so data and research pertaining to this topic is scarce. Below you can find photos of the clover crown borer in various stages of its lifecycle:
Pesticides do not have an affect on the clover crown borer because they are below the soil and nestled within the root of the clover. The use of fungi or nematodes as a delivery mechanism of the pesticide may help control the occurrence and spread of the borer population.
The red clover is one of the few plants/trees that the borer lives in. The study performed tested whether or not different pesticides used on the clover crops would impact the borer population. However, with the borer living in the soil and the roots of the plant, the pesticides could not be effective. Either there has to be a new way to deliver the pesticide to the borer or the farmer may need to try a different legume in place of the clover to decrease the borer population.
What did we learn about soils?
I learned quite a lot about the negative affects biology, specifically fauna in the soil can have on plant life. Nitrogen fixation from the red clover is very important for agriculture to take advantage of and the loss of red clover due to disease and significant effects on nutrient uptake efficiency from the clover crown borer seems like a notable issue. I never really thought that there were pests that we couldn't take care of with some sort of pesticide. This is a clear example that we still don't know everything about soil or the organisms living in it.
- Andrew Bilton-Smith
I learned that red clover can be used as a recovery crop that fixes nitrogen back into the soil. Early in the 1900’s it was also used as hay, silage, and a grazing crop. Farmers prefer red clover because it does not require irrigation to grow. I also learned that you cannot keep a field of red clover in ground for more than three or four years because the crop is susceptible to clover crown borers. The borers destroy the roots of the red clover and ruin the crop.
What I learned about soils that I did not know before was that things are not always as they seem. Although it may seem like a disease above the soil it may be something else acting upon the plant that inhibits its growth and nutrient fixation. I learned that if a farmer wants to figure out the problem with their crop, they might need to take a look into the soil and into the roots.
- Crystal Kaufman
I learned that it might be possible to control pests in soil with nematodes. I also learned that even with all of our agriculture technology there are still some pests we have problems controlling.
- David Raines
As a young farmer I have been used to thinking of crop production and pest management above the soil. I didn't realize just how many more problems can arise with the life cycles of pests in the plants and in the soil.
- Tiffany Harper
Through this project I got to learn about the clover crown borers and how they live. I knew very little about how they could burrow in the roots of the clover and how the soil and roots protected them and other mesofauna from pesticides. The main purpose of the clover is for nitrogen fixation and, due to the borer, it cannot do its job correctly.
- Kristen KasteAs a young farmer I have been used to thinking of crop production and pest management above the soil. I didn't realize just how many more problems can arise with the life cycles of pests in the plants and in the soil.
- Tiffany Harper