ALBANY - There is a new, easy way to judge the quality of your soil. Based on observation and simple tests done in the garden, the Willamette Valley Soil Quality Card can help home gardeners conduct their own soil analysis beyond what is revealed by traditional soil chemistry tests.
Willamette Valley farmers and a team of scientists from the Oregon State University Extension Service, the Agricultural Experiment Station and the Natural Resources Conservation Service developed the scorecard.
Both farmers and scientists wanted a way to measure the effectiveness of new soil conservation methods that the growers were using in their commercial fields. The scorecard is a checklist of 10 characteristics that farmers themselves identified as the most important indicators of long-term soil productivity. It condenses years of experience and education into a concise primer on soil quality for the Willamette Valley.
The checklist these farmers use to test their fields is the same list gardeners can use to test the soil quality in their own yards and gardens. The scorecard comes with a Soil Quality Guide to help users understand their observations and score the quality of their soil.
For example, one indicator measures soil compaction. Farmers compact their soil from repeated passes with heavy farm equipment. Gardeners can compact the subsoil from repeated rototilling of the topsoil. To test compaction, you simply push a wire flag into your garden soil. Does it hit hardpan and stop? Or does it pass easily below the level you have tilled? The wire flag represents the roots of your plants, and the Soil Quality Guide can help you understand the journey those roots make through your soil.
Another indicator measures soil structure. Soil that has been tilled too much can have clods that are cemented together. When broken apart, the clods disintegrate into powder. Healthy soil has tiny pockets of air and a crumbly texture. The Soil Quality Guide helps you assess if your soil is crumbly or cloddy and what difference it makes to water retention and plant growth.
Other indicators measure the abundance of soil organisms, the infiltration rate of water and the condition of growing plants. All the observations you make are scored and recorded on a single card. The OSU Extension Service has published bound sets of 25 Soil Quality Cards to help farmers and gardeners compare results in different plots and over time as different improvements are made.
The companion Soil Quality Card Guide explains the importance of each indicator, instructions for testing each indicator and what you can do to improve the quality of your soil reflected by these tests. It also outlines more in-depth tests that can be done with simple household materials.
Printed copies of the Willamette Valley Soil Quality Card (EM 8711) and Guide (EM 8710) are available for $3 each from OSU Extension and Experiment Station Communications. Send your request and a check or money order payable to OSU to: Publications Orders, Extension and Station Communications, OSU, 422 Kerr Administration Building, Corvallis, OR 97331-2119.