About soil sampling
Soon, I will be approaching 25 years in my career with UGA Extension. I started out as a 4-H agent that also handled animal science areas in Bartow County, but then shifted over to agricultural and natural resources on a full-time basis. No matter the program area, agents like myself would push the important of soil testing. Think of soil testing as a tool or resource to help keep your soils productive.
We use our soils to grow lawn grasses, home garden vegetables, ornamentals, large scale crops or pasture grasses for example. The goal of soil testing is to be a help in making your efforts more successful.
Today, I will be sharing soil testing information from a UGA circular by Leticia Sonon and David Kissel, of the UGA Agricultural and Environmental Services laboratories.
For starters, I like to say that soil testing can help you take out the guesswork. If you sample correctly, the results received from the lab should be accurate. Depending on the activity, the recommended results will come in amounts per acre or amounts per every 1,000 square feet or amount of row. You will be given amounts of needed lime to raise soil pH or a particular fertilizer with a rate.
Don’t forget that we can give multiple codes for a sample that will be sent to the lab. This means if you are starting a new lawn for example and are not 100% sure of the grass you want, we can code a sample for fescue, zoysia or bermuda. You will receive a report for each separate grass and when you do decide on the grass type, you can follow the report recommendations.
I think one reason people do not soil test is because they feel it may be too expensive. A properly taken soil test will cost you $9 including postage to be sent to the lab. Results will normally come back in five to six working days. For a lawn, vegetable garden or flower bed for example, one soil test is basically all you need.
If you are sampling large acreage, you normally will need to do a soil sampling procedure for every 15 to 20 acres. Keep in mind that taking a sample accurately is important. We only will send in one pint of the sampled soil to the lab, but that soil will be a mixture of samples taken from many spots in the area. I am sure over the years people have collected soil from one spot in the lawn for example and brought in for shipping. Those results would not be highly accurate. I would suggest taking the soil samples correctly to achieve accurate results.
Even though the soil test is $9, you will then have to go and purchase fertilizer and lime. That could be costly if you buy something you do not need because you used inaccurate results because you took samples improperly in the first place. In taking samples, the sampling depth is important. For lawns and pastures for example, you take samples to a depth of 4 inches. For gardens, ornamentals, mixed fruit trees and wildlife plots, sample to a depth of 6 inches. I will add that we do have soil sample probes that can be checked out to help in your sampling.
When taking samples you need to use a zigzag approach. This means to zigzag across the area being sampled and randomly stop eight to 10 times to collect samples. For trees and shrubs, take soil samples from six to eight spots around the dripline of the plants.
You need to use the right tools in sampling. You will need a clean plastic bucket for the samples. If you do not want to check out a soil probe from our office, you can use a trowel, shovel, spade or hand auger. Do not use tools or containers that have been used for fertilizer or lime. When you stop to take a sample, clear the ground surface of grass thatch or mulch.
If you are using a trowel for example, push the tool in the ground to the desired depth in the soil. Push the handle forward with the spade still in the soil to make a wide opening. Then cut a thin slice from the side of the opening that is of uniform inch thick and 2 inches wide that will extend from the top of the ground to the depth of the cut.
Put each sample taken in your container. Then mix the samples. We will need one pint of the mixed soil for shipping to the lab for that procedure. With rainfall, the soil more than likely will be damp. I would suggest to air dry the sample overnight on a flat service that is lined with clean white paper.
If you are conducting multiple sampling procedures, make sure you have a numbering system or some way for you to know where the samples came from.
Finally, check us out at our UGA Extension-Gordon County web page or follow us on Facebook at Gordon County Extension/Agriculture and Natural Resources.