Why Soil Testing is Important


To Test Or Not To Test

Article by Wayne Batten

If your car or boat has set around without being operated since last fall, would you get into either one and set out on a 90-day trip?  I don’t think you would.  Are you planting crops, gardens or other plants in the coming days?  Have you tested your soil?  If not, there is not much difference in planting your crops without a soil test and beginning that 90-day trip without checking your equipment.

I know by now you may be saying, “You Extension people are always harping about soil testing” and you would be correct.  Soil testing is that important.  How many of you are guilty of adding some fertilizer and or some lime and expecting the plants to grow?  Maybe they will grow as expected, maybe they will not.  A simple soil test can prevent many problems seen each year by Extension Agents and others.

How do I need to pull soil samples?  Begin by drawing a map of your farm, home lawn, garden or whatever areas you will be sampling.  Look over the terrain.  Do you notice any obvious changes in soil color, texture, any changes in weeds growing there now?  If so, you may need to make each of these “different” areas a new sample.  Be sure to label the map you have drawn with names, numbers or some means to be able to distinguish where each sample came from when you get the results in a few days.

Now you are ready to begin pulling soil samples.  You will need a soil probe or a shovel, a plastic bucket, soil sample boxes and a pencil.  If your soil probe or shovel is rusty, clean it first.  Never use a galvanized bucket for collecting samples.  If you do so, many of the micronutrient results will be incorrect.  From each area you plan to sample, dig down about 4 to 6 inches and collect some of the soil from throughout the area. Pull a sample like this from at least 10 places for each different area on your map.  Mix the subsamples well in the plastic bucket and pour the mixed soil into the soil sample box.  Be sure to label the box with the appropriate name or number so you will know where that sample came from when you get the results back.  Soil sample boxes are available at your local Cooperative Extension Center and at many farm and garden centers.  You can mail your samples to the lab in Raleigh or bring them to most Extension Centers and we will send them off for you.

By now, you may be saying to yourself, this sounds like too much work, I will just apply some lime and fertilizer and let it grow.  Would you add oil to that engine before beginning a trip without checking the level on the dipstick first?  I don’t think so.  Adding lime and fertilizer without a soil test is the same thing.  Many people think you cannot add too much lime to soil.  That is very wrong.  Micronutrient deficiencies are very common in many areas of North Carolina, especially on sandy soils in the southeast.  Too little lime results in a low pH whereas too much lime may lead to a very high pH.  Different crops have different pH requirements.  When soil pH levels get out of the desirable range, nutrients like iron, manganese, boron, copper and zinc become less available to plants for uptake.  Often the symptoms exhibited by the crop may look similar with a pH that is too high or one that is too low.

By soil sampling, you can potentially save money that might otherwise be spent on unneeded lime and fertilizer.  Many of the soils in Sampson County have had routine phosphorus applications for many years.  Phosphorus does not leach out of the soil very quickly and many soils now have adequate levels in storage.  Most tobacco farmers have found they are able to save a lot of money by applying fertilizers without phosphorus.  You only know if you have adequate phosphorus levels by soil sampling.

Article courtesy of North Carolina State University Cooperative Extension

Link Photo courtesy of NRCS Soil Health


For more information about soil check out Susan Penstone’s excellent article The Real Dirt on Soil.

What’s your view on soil testing?

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