The Magic Valley Soil Health Forum took place on February 12 in Twin Falls at the College of Southern Idaho campus. The forum provided an opportunity for producers to gather and discuss topics in a group setting. There were 11 breakout sessions on such topics as reducing tillage, making and using compost, soil biology, livestock integration and economics, soil health economics and using data to make decisions among others. The day started out with introductions from the speakers and a new section called the “Hall of Shame” where producers shared a mistake or two that they have made along their soil health journey. As Ladd Wahlen, a producer near Aberdeen, commented "these are not failures, but learning opportunities and hearing about them is just as important as learning about success stories." Josie Erskine of Peaceful Belly Farms in Caldwell then discussed their success with receiving funding for innovative projects and ideas, and shared information about how other producers can go about this process to do the same.

Attendees were able to choose from four different breakout sessions at a time. One notable breakout session, hosted by Kurt Heward and Ryan Streadbeck of Heglar Creek Farms, included discussion on soil biology. The two went into detail about how they use a microscope to get a better understanding of the biology in their soil, with an overarching goal of increasing nitrogen (N) efficiency. In one trial, they decreased N application on one field to 100 units and 140 units, compared to their standard application of 180 units in other fields. In the field with the reduced N application, they were able to identify an abundance of nitrogen fixing microbes, which were not detected in the fields with a standard N application rate. Also, the field with reduced N yielded slightly higher than the standard rate, leading to overall savings from reduced inputs and increased yield. Kurt and Ryan ended the session emphasizing the importance of documenting the tests and experiments producers run, so that the information may be shared with others who want to learn.  

• University of Idaho Soil Heath: Soil Health | University of Idaho Extension
• University of Idaho IAMP-Idaho: iamp.uidaho.edu/ 
• Idaho NRCS Soil Health: Idaho Soil Health | Natural Resources Conservation Service
• University of Idaho Soil Health YouTube (featuring virtual field days across Idaho and recordings of past 5 for 5 rountables): University of Idaho Soil Health YouTube 

There are a variety of lab tests available for quantitatively measuring soil health parameters. Soil organic carbon (or soil organic matter) percent is an excellent metric to measure and keep track of but can respond quite slowly to management changes. Including additional tests that look at other aspects of soil can help with monitoring soil health over time.

This publication from WSU Extension is a great resource for understanding several soil health tests: A Practical Guide to Soil Health Indicators for Monitoring Shifts in Soil Organic Matter. For each soil health indicator listed, the guide explains availability of this test in the Pacific Northwest, what it measures, and its relevance for monitoring changes when different conservation practices are adopted.

The relationship between potentially mineralizable carbon (PMC) and permanganate oxidizable carbon (POXC) is particularly interesting and is explained very well in this guide. PMC measures microbial activity in the soil; higher PMC indicates microbes are actively releasing nutrients from organic matter decomposition. On the other hand, POXC measures a specific fraction of total organic matter, and increases in this value are associated with higher levels of carbon accumulation and stabilization in soil. These two measurements are best interpreted alongside each other, because if PMC is increasing, while POXC is decreasing, this indicates soil organic matter is being lost over time. However, if both values are increasing, it suggests gains in soil organic matter over time while biological nutrient cycling is occurring. These two tests can help a landowner detect and predict trends in soil organic matter and soil health changes over time. Tests that detect soil properties which change quickly can be encouraging for growers on the path towards building soil health.

Nearly all the soil health tests mentioned in this guide are available through the NRCS CEMA (Conservation Evaluation and Monitoring Activity) 216. Read more about this CEMA at this link: CEMA 216 Soil Health Test. The NRCS will pay for a qualified individual to both collect soil samples and have the samples tested in a lab. A group of Basic Soil Health tests are available, or single indicators can be selected. The single indicators are selected by first using the In Field Soil Health Assessment to identify resource concerns. The CEMA 216 is flexible as far as which tests are scheduled. Soil health testing is encouraged to be used before and after applying a soil health conservation practice.

What would you like to see in the “In the Literature” section? Please reach out with any comments/feedback: ccosdon@uidaho.edu and tasha.harder@usda.gov

The Idaho NRCS Soils/GIS team recently presented a series of “Lunch and Learn” webinars on soil topics and resources. Check out this recording on the Idaho NRCS Youtube channel to learn more about World Soil Day (occurs every year on December 5). This recording focuses on soil-water relationships and the soil health principles.