A video demonstration of measurements of soil structure in orchards including water infiltration and compaction. Authors Tianna DuPont, Andy McGuire, David Granatstein, WSU Extension. Recording from WSU virtual workshop Soil Health in Orchards with project support from the Washington State Tree Fruit Research Commission.
Text Transcript and Description of Visuals
| Audio | Visual |
|---|---|
| Another indicator of soil structure is water infiltration. We measure water infiltration by pounding a ring into the soil and recording how long it takes for one inch of water to infiltrate. | Title card reading “Soil Structure: Part 2”, shown over footage of a metal ring embedded in the soil and filled with water. A stopwatch to the side times infiltration. |
| In soils with lots of aggregation and low compaction, large pores caused by earthworms and plant roots will allow water to infiltrate quickly and little water will run-off. | A split screen shows three water infiltration rings in different types of soil. Each ring contains water, with a stopwatch placed next to each. On-screen labels above the rings read “Low water infiltration”, “Soil with earthworm pores”, and “Mow and Blow Organic”. |
| Management practices in orchards can impact soil structure. For example, in this soil at right, the tree row is mowed and mulched and soil organisms have created good soil structure. | In the right panel, the water level drops rapidly, and a stopwatch shows an infiltration time of 25 seconds |
| In the center panel, plentiful earthworms have created channels for water infiltration. | In the center panel, the water level drops more slowly and a stopwatch shows an infiltration time of about one minute and thirty seconds. |
| In the left panel, surface compaction is limiting water infiltration and likely root growth. | In the left panel, the water level drops only slightly, and does not fully infiltrate during the demonstration. |
| We can also see soil structure differences with these run off boxes. In the orchard at left, a much greater portion of water infiltrates into lower soil depths. Greater pore space creates a good environment for tree roots and soil microbes. | Two run-off boxes are shown side by side. The left box is labeled “Orchard with mow and blow, organic, no cultivation”, and the right is labeled “Orchard with standard herbicide weed strip”. Water flows through both boxes. The soil on the left releases less run-off, while the soil on the right produces a stream of run-off into the collection container below. |
| In multiple studies, we have seen that woodchip mulch can also increase water infiltration. | Two run-off boxes are shown side by side. The left box is labeled “Orchard with wood chip mulch”, and the right is labeled “Same orchard, no mulch”. Water flows through both boxes. The mulched soil releases less run-off, while the unmulched soil produces a stream of run-off into the collection container below. |
| Soil structure can be disturbed by compaction. | Title card reading “Compaction” over a close up image of a hand holding a compacted clod of soil. |
| Soils may have a surface or deep compacted layer where soil particles are pushed close together, limiting root growth as well as access to water and nutrients. | Close up image of a hand holding a compacted clod of soil. |
| We can estimate compaction by measuring the force required to penetrate the soil, using a soil penetrometer. | A person walks up to an orchard row holding a penetrometer. |
| Push the tip of the penetrometer into the soil using slow even pressure when the soil is at field capacity. | She pressed the penetrometer probe into the soil, looks at the reading, then removes the probe. |
| When the gauge reaches above 300 PSI, compaction may be impacting plant roots. | Overhead view of the pressure gauge of the penetrometer as it is pushed into the soil, showing a PSI above 300. |
| End card displays “Soil Health in Orchards Workshop” with an illustration of a tree and links to additional workshop resources. |
Link to YouTube video: Soil Structure: Water Infiltration and Compaction Demonstration
