Turf Tips >>>
How to Take a
TURF SAMPLE “Send
a sample to the lab.” That’s familiar advice for all turf managers, but an accurate analysis depends on having the right sample. A soil test, a disease diagnosis and a nematode analysis all require a different kind of sample to be effective. Are you always sending the lab what they need to answer your questions?
Al ab am a Tu rf Tim es >>> S pr ing 20 13
Soil sampling For a soil test, soil should be collected from many sites within the turf area of interest. The soils should be combined and thoroughly mixed in a plastic bucket (metal containers will skew nutrient analysis), and about one pint of the resulting soil mixture should be sent to the lab for analysis. Be sure not to sample too deeply for a turf soil test. Grass roots are usually in the top 6" of the soil, so there is no need to sample and analyze soil that is too deep. Test only the soil in which grass roots can be reasonably expected to grow. Also, it is important to send in separate samples from areas with different soil textures, colors, drainage or other physical properties. And, of course, if you are sending samples to try to troubleshoot a problem with turf, send in separate soil samples from healthy and problem areas, in order to compare the two. When sending the soil, be sure to provide the lab with the species
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and variety (if known) of grass you wish to grow, and indicate whether the soil is for a lawn, athletic field, sod farm or golf course rough/tee/ fairway/green. This will help the lab make the correct recommendation. At the Auburn soil-testing lab, a standard soil test gives results for soil pH, phosphorus, potassium, calcium and magnesium. For an additional fee, micro-nutrient analysis (copper, iron, manganese, zinc, boron, molybdenum, aluminum, cobalt, chromium, lead and sodium) is also available. The lab also provides foliar nutrient analysis and irrigation-water testing.
Disease determination For a disease diagnosis, the most important part of sampling is to capture an area where active infection is taking place. This is usually at the edge of an affected turfgrass area. Samples taken from the middle of a large dead patch most often are not useful in diagnosis since the fungus that killed the grass has already moved on and other scavenger fungi have already begun to break down the dead turf. Collect an entire plug from the edge of a patch or ring, or if dead spots are small, collect a plug of turf containing one or more entire spots, plus some healthy turf. Be sure to include soil and roots; even if you think the problem is a foliar one, having an entire plant and some soil will make the diagnostician’s
job much easier. There is no need to dig too deeply. As in soil sampling, any soil from below the zone of root growth won’t help with a diagnosis. If you are mailing the sample to the lab, place it in a plastic bag inside the box but leave the bag unsealed. Sealing a sample in an airtight container will probably result in the whole sample rotting away before it can be analyzed. Placing a moist paper towel in the bag will help keep the sample from drying out; again, though, do not seal the sample in an airtight bag. Sending the sample by overnight delivery will help to ensure that it will be fresh when it reaches the lab. Whenever possible, time the sending of samples so that they will not spend an entire weekend en route. Include the following important information: grass species and variety, weather conditions under which the symptoms first appeared and cultural practices used on the turf (such as mowing height, fertilizer applications and any herbicide or fungicide applications). Photographs of the entire turf area can also be very helpful.
Nematode analysis For a nematode analysis, take samples in a manner similar to a soil test. Since nematodes are not uniformly distributed in the soil, it is important to take many small samples and combine them before