In any agricultural activity, the first step is soil testing. This gives information about the soil’s fertility and its physical and chemical properties. To obtain such information, analysts use soil test kits for on-site testing. Analysts can then determine if the soil is viable for planting. They can also determine what should be added to the soil to improve its fertility.
Another important factor is the soil’s nutrient availability to plants. One way to determine that is by measuring the pH. Varying pH levels affect the chemical forms of the soil’s nutrients. This limits the presence or amount of nutrients that plants can absorb.
Aside from knowing soil fertility and pH level, analysts also perform testing to determine the presence and amount of nitrogen products and other composites of fertilizers. One reason is nitrates and nitrites can be toxic to the aquatic environment if they are leached through the ground.
It is important to obtain quick and accurate results about the soil’s fertility, pH level, and possible toxicity. This led scientists to develop rapid soil test kits that are cost-effective and easy to use. Many soil test kits can also help analysts test for both single and multiple parameters.
As with other analytical methods, analysts should take extra care on soil sampling. Analysts consider water content, soil layers, and sampling areas. High water content in soils can show lower amount of nutrients. Different soil layers (from 0-90 cm in depth) can give information about nutrient distribution. Obtaining samples from different areas can provide comprehensive results about the soil’s properties.
To obtain more accurate results, analysts can spread the samples on a flat surface and air dry them overnight. This is to reduce the water content which affects the quantification of soil nutrients. Then the samples from all sampling areas are mixed well together.
An extracting agent will then be used which would react with the soil sample. The next step is using test strips. These strips change in colour and will then be compared to a colour scale. In other test kits, a colour-forming agent is added instead. The solution will change colour and will then also be compared to a colour scale.
As discussed earlier, soil testing kits can test single or multiple parameters. These parameters include pH, nitrogen (as nitrate, nitrite, or ammonia), phosphorus, magnesium, manganese, calcium, iron, chloride, sulphate, and potassium.