Lerato Botha, a fiery farmer and the CEO of Farmerlee Farms in Tarlton, Gauteng, knows all about soil. That’s because she’s an agronomist – someone who studies ways to make crops grow better. And one of the things that impacts crop growth the most, is the soil in which they are planted.
“It’s very important for farmers to know the makeup of their soil,” Botha says. “This will help determine the type of crop they can grow.”
Various crops require specific types of soils so they can give you your optimum yield, according to Botha. She names the three main types of soil: sand, loam and clay. But more often than not, one could have a combination of the three.
“Sandy soils tend to drain water faster than clay soils which retain water,” Botha says. “This is why it’s important to know your soil type before selecting your type of crop.”
How to select your soil for testing
You can’t just pick up a bucket of soil from your farm to test. Here are Botha’s steps to testing your soil:
1. Divide your land
“It’s important for farmers to divide their lands when taking tests,” says Botha. “This will allow for more accurate soil results.”
2. Randomise your selection
Farmers should select soils from random parts of the field, says Botha. This allows you to get a good overall description of the soil on your farm.
Botha suggests using a W or Z pattern to guide you to different parts of the field to test at random.
3. Select your soil sample
Soil samples should be taken by removing some of the top layer of soil and then collecting a sample of up to 200mm deep. The minimum amount of soil required for testing can be about four hands full.
“It’s important that only the topsoil is tested and not the subsoil layers underneath,” says Botha. “This is done because the roots are more likely to use the first 200mm of the soil.”
Once you have successfully extracted all the necessary samples, you can take it to a lab where they run tests on the soil.
Take care when sending in your soil samples
Botha mentions some important aspects of the soil collecting process to remember:
- The instrument (spade) that you use to collect the soil samples should have no other residue on it. You need to clean it for every sample you take.
- Store the soil in a clear plastic bag when collecting and transporting it. Remember to label the sample.
- The soil should not be wet when samples are taken.
The first step to knowing what is in your soil, is getting a lab to test it for you. Botha’s advice is to select a SANAS-certified lab.
“This lab is important as your regulatory bodies such a Global Gap, etc., require results from these labs,” says Botha.
Once you get to the lab, they’ll ask you what sort of tests you would like to run on your soil. You can then tick all the boxes you require. Results are usually ready within five to ten working days, according to Botha.
“You can test for things like your pH, macro and micro-nutrients, your carbon levels in the soil and so forth.”
Once you have your results, you can consult an agronomist or your preferred seed company. They can suggest what crops you can grow and the amount of fertiliser you will require for the growing season of the crop.
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