Sodium Affected Soils
Thoughnot a plant food nutrient, sodium plays a critical role in soil and turfgrass health. The primary problem posed by high sodium is not a toxicity hazard, but a rapid decline in soil structure that can begin when sodium base saturation exceeds the critical 5% level. High sodium reduces soil permeability, resulting in drainage and compaction problems that cause a decline in turf vigor. For the turfgrass manager it’s critical to understand how sodium accumulates in the soil and what steps can be taken to amend high sodium levels.
The primary cause of soil sodium accumulation is poor quality irrigation water, but its not just water-borne sodium that creates the problem. A number of other factors influence the sodium permeability hazard of irrigation water, such as bicarbonate and calcium levels.
If irrigation water poses a sodium permeability hazard a number of treatment strategies can be employed, depending on water quality and soil type. Irrigation water treatment has become a hot topic in recent years, in part due to the increased reliance on poor quality municipal effluent water. But treatments are often over-prescribed or sold to treat sodium related problems that simply don’t exist. Before making amendment decisions ensure that your soil and irrigation water quality analysis is conducted by an accredited, reputable laboratory. Moreover, seek the advice of a Professional Agrologist before deciding on your amendment or treatment options.
Laboratory Soil Analysis
DIRECTIONS FOR TAKING SOIL SAMPLES -
STEP 1: Use soil profiler or other tool to obtain soil samples to the maximum depth possible. The depth indicates how loose the soil is. The deeper the soil sample the better it is for the turf or other plant materials.
STEP 2: Twist probe and pull out of ground. Measure from surface line to bottom of probe, the bottom of area "C" on the photo. If using a trowel or shovel, attempt to create a flat surface that is perpendiculat, removing the loose dirt out of the way so that it can be seen more from the side and to enable an accurate measure of the depth. Write down "Average Coring Depth" so that it can be transferred to the form.
STEP 3: Push plug up from bottom of probe. Carefully fleck away soil until you expose beginning of roots. Sometimes, the roots are visible at the bottom of the probe. Measure from surface to end of root system. If using a trowel or shovel, measure the depth of the roots, similar to using the probe, by scratching some dirt away to determine the deepest part of the roots, from top of soil to bottom of "B" on photo. Fill in "Main Root Development" with this figure.
STEP 4: Measure the depth of thatch. That's the peat-like or corky material from the grass line to beginning of soil surface, area "A" on the photo. Fill in "Thatch Layer Depth" with this figure.
STEP 5: Remove soil from probe (or trowel), discard thatch and grass, put soil in sample bag. You will need to repeat Steps 1,2, & 5 till there is 1/2 to 1 cup of soil in the bag (Zip Lock).
STEP 6: Fill in the "Regular Cutting Height" at which you cut your lawn.
STEP 7: Fill in "Type of Grasses" in your lawn if known (not a critical).
STEP 8: Measure the turf area for which the sample was collecte
STEP 9: Check off watering method you use.
STEP 10: Check off correct lawn life stage. "Developing" means lawn was established within the last two years. "Renovation" means lawn was established but needed extensive seeding last season which was done. "New-seeded" - self explanatory. "New Sod" - self explanatory. If any other condition exists, note in blank area.
STEP 11: Date sample taken and last time lawn or garden was limed.
STEP 12: Transfer the Data onto this Form
STEP 13: Send $49 along with soil sample in Zip Lock bag to: Prescription Soil Analysis, LLC, PO Box 708, Dillsburg, PA, 17019
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