Developing Digital Tools to Improve Soil Sampling and Analysis for Sustainable Agriculture in the Western U.S

Developing Digital Tools to Improve Soil Sampling and Analysis for Sustainable Agriculture in the Western U.S

Summary

Digital Series Overall Description

This series of videos can be used either as guidance for a soil-related demonstration in a classroom setting or to illustrate soil processes such erosion, runoff, and infiltration that would be difficult to set up and conduct at a meeting, conference, or classroom.

Sometimes educators and extension specialists might want to reach a large audience, but the demonstration is too difficult to see from the back of the room or is too laborious to set up in the time allotted or it doesn’t work like you wanted it to. These high-quality videos are easy to see and hear or can be projected while the presenter describes what is going on. They can also be played as a stand-alone demonstration with audio.

The animations are ideal for gaining an understanding of:
• How to choose the best soil test for phosphorus in arid, high pH soils, and calcareous soils.
• The effects that salinity, calcium (Ca++), magnesium (Mg++) and sodium (Na+) have on water infiltration, and how plant-available water is affected by salts in the soil.
• The sodium adsorption ratio (SAR), considering soil salinity with respect to the calcium, magnesium, and sodium content in the soil and the relationships among the three ions (Ca++, Mg, ++ and Na +).
• The effects of total salt in the soil, showing the learner why less water is available to plants in the presence of salt. This particular animation is more of an advanced topic for professionals already familiar with the terms.

The link to the videos and animations has been shared with the Western Region WERA-103 Working Group and their colleagues. We anticipate feedback from this pool of professionals by December 2016. The region covers HI, WA, OR, CA, ID, UT, AZ, WY, CO, NM, MN (new member), and Saskatchewan. A formal discussion about the videos and animations will be included in the Western Region Nutrient Management Conference in 2017.

Objectives/Performance Targets

OUR CONTENT: Concepts that we believe to be critical to sustainable agriculture in the west, such as saturated paste, salinity, leaching, water holding capacity, appropriate soil tests, and properly executed soil testing were parsed into sixteen separate videos or animations. This keeps the viewing time to a minimum yet addresses the importance of each concept.

Demonstration Videos / Animations and Brief Description
1) Soil Particle Size (2:56). The naked eye cannot see the different size fractions in soil or the spaces that exist in soil. A glass jar, beads of various sizes, and a golf ball or two shows the size fraction differences in soil along with air spaces and water (if added).
2) Water Infiltration (9:08). A sponge illustrates how water moves through soil and the forces that control its movement. Terms covered include infiltration, matric potential, gravitational water, saturation, drainage, field capacity, wilting point, and runoff.
3) Effects of Ground Cover (2:31). Protecting the soil surface with mulch helps reduce soil erosion and increase water infiltration. Four soil boxes with increasing amounts of surface cover from plant material illustrates how soil that is protected by plant material when water is applied as rain or irrigation reduces sediment and water loss from the soil surface.
4) Runoff and Infiltration as affected by soil cover (5:54). This video captures both the water that runs off the soil and the water that infiltrates into the soil as a function of soil cover using a rainfall simulator.
5) Surface Cover, Runoff, and Infiltration (3:04). Soil from bare ground is compared with soil with a living cover of pasture grass to illustrate the effect that plants have at reducing soil loss to runoff and increasing the amount of water that can infiltrate into the ground.
6) Soil dispersion and flocculation (aggregation) (4:10). This demonstration shows the effect of calcium (from gypsum) on bringing dispersed soil particles together as aggregates to aid in reclaiming soils with high levels of sodium.
7) How Calcium from Gypsum Helps Sodium Affected Soil (1:23). Water movement through a sodium affected soil is improved by the addition of calcium from gypsum. Water that is applied enters into the soil and continues to wet the profile in the presence of calcium.
8) Soil sampling (1) (6:04): Getting Started: Purpose behind soil sampling, tools, preparation prior to sampling, sampling depth, representative sample, volume to submit, sample container, and labeling.
9) Soil Sampling (2): Probe versus shovel (4:18). Procedures for sampling soil with a shovel versus a probe.
10) Soil Sampling (3) from a small field or garden (3:42). Method of random sampling of a small field with a hammer probe. How to prepare the collected soil for shipment or delivery to a lab. How much to send.
11) Soil sampling (4) from a large field (3:20): Hammer probe demonstrating random sampling across a large field. Proper mixing, preparation, and volume for shipment.
12) Soil sampling (5) when textures vary by depth (2:50). Soil maps can be useful to plan ahead in sampling soil. What to do when soil texture changes abruptly in a field.
13) The Saturated Paste Method (6:47). A demonstration showing what a saturated paste of soil is like compared to 1:1, 1:2, and 1:5 ratios of soil:water. Saturated Paste method is the standard method by which management practices are developed for saline soils.
14) Why Choose Olsen P for Western Soils. This animation makes the case for why soils with alkaline western soils should be tested for plant available phosphorus using the Olsen method.
15) What is SAR? How do salinity, calcium, magnesium, and sodium affect soil water infiltration and management decisions? This is an advanced animation for instructors teaching other professionals. It explains the effects the three ions of concern along with the salinity of the soil.
16) Unavailability of water in saline soils – animation. This is an advanced topic for those that are primarily teachers.

OUR OBJECTIVES:
For the remainder of the grant period we will be in contact with WERA-103 members and other professionals to assess:
1. Understanding of the unique problems of testing soils in the west and proper procedures needed to obtain a reliable soil test.
2. Confidence of targeted agricultural training professionals in adequately explaining to their agricultural producers the unique problems testing soils in the west and the proper procedures needed to obtain a reliable soil test.
3. Understanding of the concepts by targeted small farm owners (using established benchmark date) who understand the importance of soil testing and collect samples according to prescribed protocols.
4. whether or not targeted agricultural professionals and producers recognize why Olsen phosphorus is preferred in most western (high pH) soils.

The link to the videos and animations has been shared with the Western Region WERA-103 Working Group and their colleagues. We anticipate feedback from this pool of professionals by December 2016. The region covers HI, WA, OR, CA, ID, UT, AZ, WY, CO, NM, MN (new member), and Saskatchewan. A formal discussion about the videos and animations will be included in the Western Region Nutrient Management Conference in 2017.

Accomplishments/Milestones

All videos and animations have been posted to the following website:
Digital Tools for Soil Sampling, Analysis, and Soil Properties
A link to the website will also be shared from http://scienceofagriculture.org

Impacts and Contributions/Outcomes

Feedback regarding the videos and animations has been very favorable. Our final report will provide a better picture of how well these products have helped in understanding key concepts in soils and soil testing.

Collaborators: