A soil test is a perfect method for examining the fertility level of soil and providing some valuable information for farmers to help them keep up with local fertility programs. If you want to grow healthy cash crops and make good money, you first need to figure out the condition of the soil and if it is necessary to manually increase the soil’s fertility.
You can always use a self-made kit for a soil fertility test, so there is no need to worry about the cost of getting a good fertility test equipment.
A basic pH test can measure soil’s acidity and sometimes even its nutrient content. For this simple test, all you need to do is buy the kit at a nursery and carefully follow its instructions to get information about your soil’s pH and fertility balance.
The kit test, however, cannot guarantee the exact measure of the nutrient and pH levels in your soil; for this purpose, you need to do a much more test to find out the soil’s fertility level. There is a big programme, ‘spread it West Africa’, whose aim is to help African people use more dependable kits to test soil fertility.
“A special interest is, therefore, being devoted to the use of mobile soil testing kits because of their simple nature which makes them user-friendly by farmers, extension workers and agro input dealers. This is relevant, especially if the soil testing kits would provide meaningful data about fertility and nutrient limitations of soils that would allow adequate fertilizer formulation,” - USAID West Africa Fertilizer Programme.
Along with the self-made kit, you can use the electromagnetic induction sensor. This sensor works to measure soil electrical conductivity, texture, salinity and organic matter content.
READ ALSO: Types and uses of soil in Nigeria
Top soil fertility testing methods
When it comes to soil testing, there are three critical steps: sampling, analysis and the results.
There are two approaches to the testing procedure: the traditional one carried out in the laboratory and the other one which can be done right on the spot. The last one is the modern method of soil scanning. Let's find out more about these two methods.
Taking soil samples
When you plan to do the soil test you have to take some samples of the area. In order to have the most accurate interpretations and recommendation based on the soil test, you need to follow some specific and strict sampling procedures. If there are any mistakes during the soil sampling procedure, such as wrong depth sampling or any incorrect figures are taken, the result of the sampling will be incorrect.
Whether you plan to use a do-it-yourself kit or send the sample to a soil laboratory, you should start by preparing a soil sample. For that, follow these easy steps:
- Take a cup and fill it up with soil (4 to 6 inches of soil) and place it in a plastic bag.
- Dig up six more similar samples from different parts of your garden or field.
- After that, mix all the samples of soil together and place only two cups of the mixed soil in a plastic bag. This is your soil sample for testing and further analysis.
- After that, you can use the portable potassium ion specific electrode to carry out a test to measure soil fertility.
Spectroscopy soil test and soil analysis
Now it is time to analyse your sample. Keep in mind that it is better to use soil-testing methods suitable for the area where you grow your plants or crops; otherwise the testing and analysis will not be accurate. In order to determine what kind of test is needed, you need to do an extensive research and keep on searching for best conditions.
Soil tests that do not require the use of chemicals are quite rare, but can be done. If you use the spectroscopy method, the test is made using light which is reflected by soil. Near Infrared Reflectance (NIR) and Mid Infrared Reflectance (MIR) can give you detailed information about all components in soil and its texture. Rontgen (or X-Ray) Fluorescence (XRF) Spectroscopy gathers data about minerals and elements present in the soil.
There are some soil samples which can be analyzed with several different techniques, for example, HPLC, XRF, ICP-MS, FTIR and laser diffraction. Machine test is also a new way to analyze soil’s components using sensor data.
For analysis, you do not need to worry about the lab’s quality ratings or user-friendly recommendations. You just need to make sure the laboratory uses the method of analysis which suits the Nigerian soil conditions. Surely, it is simpler to send the soil samples to laboratories in other countries, but if that laboratory does not use methods suitable for Nigeria’s local conditions, the recommendations and interpretations will be absolutely incorrect.
If you want to compare the information given by a laboratory with other laboratories, you also need to make sure that they all use the same method of testing and analysis. Different methods of analysis are used by laboratories in the country but each of them have both advantage and disadvantages.
Soilscare scanner and interpreting the results of soil fertility tests
If you use the Soilscare scanner for carrying out soil fertility results, then you do not need to do any further analysis. Once you scan the soil, you will get instant results.
The result of the laboratory analysis is very important but the proper interpretation of results is even more important for correct recommendations. When using, for example, portable potassium ion specific electrode for the soil test, you need to pay attention to the reactions and interpret them well.
The calibration research, the soil test level and crop yield tests are three very important tests which can help you understand the soil’s fertility level.
If soil test levels continue to rise, yield reduction can occur in some areas. Once the specific response curve has been defined through field research in the area where the soil test will be carried out, the soil test interpretation levels can be recognized.
There are no average terms for the soil-testing categories, proper attention should be paid to interpreting balance of nutrients in soil test results.
There are also some in-season soil fertility tests specially designed for different seasons - some you can do yourself, while others must be carried out in a lab. But no matter what kind of test you decide to go for, make sure you take the soil sample prior to the maximum N period to ensure correct results.
READ ALSO: Characteristics of rainy season in Nigeria