Soil Sampling / Analysis
The quality of your soil is at the heart of your farm, soil testing is an important tool for evaluating and / or avoiding problems of nutrients balance.
To achieve good yield and quality, nutrient balance has to be maintained. Nutrient imbalance may result in deficiencies, toxicities or interference of one nutrient with the absorption of others. This may result in stress to the crop, causing a decrease in quality and/or yield.
At Southern Fuels& Farm Supplies Ltd we can offer you soil sampling tests. Your area representative will analyse the report and will assist you in making the appropriate changes to your soil.
Guidelines to taking a soil sample
- For sampling purposes divide the farm into fields or areas of between 2 – 4ha.
- Take separate samples from areas that differ in soil type, previous cropping history, slope, drainage or persistent poor yields.
- Avoid any unusual spots such as old fences, ditches, drinking troughs, dung or urine patches or where organic manure or lime has been heaped or spilled in the past.
- Do not sample a field for P and K until 3 – 6 months after last application of fertilizer P and K (now is a good time to soil sample). Where lime has been applied allow a time lag of 2 years before sampling for lime requirements.
- Follow a ‘W’ soil sampling pattern to ensure that the sample is representative of the entire field. Ensure that all soil cores are taken to the full 100mm depth. Place the 20 cores in the soil box to make up the soil sample.
- Write the field number and sample number on the soil box.
- Recommended Soil Sampling Pattern:
Apply lime as required to increase soil pH up to target pH for the crop. Maintaining the
soil pH at the optimum level will increase the microbiological activity of the soil, and
result in better soil nutrient recycling and release. Soil pH is also critical for maximising
the availability of nutrients applied in organic and chemical fertilizers.
Soil pH should be the first thing to get right if soil test results show a lime requirement.
Lime should be applied to neutralise acidity and raise the pH.
Over-liming can be an issue in some circumstances, especially in grassland where there is
a history of high molybdenum (Mo) in soils. It is advised not to raise the pH above 6.2 in
these circumstances, as high Mo can cause copper deficiency in animals.
It is also important not to apply too much lime in a single application, as it can make
some trace elements unavailable.
The aim of P and K nutrient advice is to maintain all fields at the optimum soil fertility
level. The soil test measures the plant available P and K in mg/L of soil. For simplicity, this
result can be categorised into a soil Index for each nutrient. The soil Index system divides
soils into one of four soil Index levels based on the soil test result. The soil Index indicates
the expected response to nutrients applied. For example Index 1 soils are very responsive
while Index 4 soils have sufficient soil nutrient reserves and usually do not respond to
fresh P and K applications