Most research today supports soil sampling and testing as a best management practice. Growers should take the opportunity learn as much as possible about their soil in order to produce their best yields. This includes knowing what nutrient deficiencies exist in their soil.
The following explains the process of soil sampling, and highlights key data growers will learn from testing and analyzing their soil.
The Soil Sampling Process
The primary objective of soil sampling is to provide a representative sample of the fertility within the field.
Based on the variability throughout the field, the number of acres per sample will vary.
- If soils are similar in texture, slope, previous crop and production practices, then the number of acres per sample can increase.
- If soils within a field are variable, than those areas can be sampled separately to determine the needs in those specific areas.
Most research suggests that growers choose 15 to 20 random areas to be sampled within the field.
- These individual areas should have multiple cores taken at six to eight inches deep for common soil samples.
- The cores can be collected using any number of tools available for this purpose.
Field composite samples, normally 8 to 16 oz. of soil, can be co-mingled and then a sample of the collection is sent to the lab.
If the field is divided into different zones, repeat the process for each zone. Samples need to be labeled for tracking purposes. Field maps can help with tracking.
Once samples are collected, they can be submitted to a local university or commercial lab via their submission guidelines. Charges for the samples will vary depending upon the testing requested.
What Will We Learn From the Samples?
The more data collected, the more information growers will have available to help them make decisions. With soil sampling, an abundance of data is available, but for growers the most valuable information will boil down to five broad groups:
- Organic Matter – The measurement of plant and animal residue in soil, which often serves as a reserve for nutrients.
- Soil pH – A measure of acidity or alkalinity of the soil. Soil pH can affect nutrient availability.
- Cation Exchange Capacity (CEC) – measures the soil’s ability to hold cationic nutrients. CEC can also be used as an indicator of soil texture.
- Nitrate-N – This form of nitrogen is water-soluble and is readily available for plant uptake. This information will help growers determine nitrogen needs.
- Extractable Macro and Micro Nutrients – These results provide the essential nutrients that are available to the plant. Normally listed in parts per million, these results can help to determine nutrient applications needed by the crop to produce maximum economic yield.
As growers and their nutrient advisors receive more information about these five areas, they will be able to make more informed fertility decisions. They will also be able to address potential issues during the early stages to help attain their overall goal of achieving better yields.
Original Source: Leaders of In-Furrow Technology, West Central