Our corn and soybean plants depend on the soil to provide adequate nutrients to grow and provide maximum yield. As growers and agronomists, we must manage that soil balance to maximize growth and profitability. This is why one of the best crop management practices we can do is soil sampling. Soil tests are inexpensive and measure the pH and nutrient components of your soil. Having this information is beneficial for making economical and environmentally responsible nutrient and fertilizer application decisions. The first step to a successful 2017 begins with testing your soil now.
Although many nutrients, such as phosphorous and potassium, can be tested at any time of the year, we also need to take a close look at pH and buffer pH. Fall sampling allows you to do this and to reflect on the previous season while it’s still fresh on the mind to address any shortfalls you may have had. Keep in mind that you do not want your fall test values to fall short of mid-range. If they do, this could indicate that your nutrient levels have been completely depleted.
Most importantly, sampling in the fall will give you dryer and better weather conditions as well as ample time to process and make your nutrient application decisions. Heavy spreader trucks in the spring increase compaction and shorten your window of application opportunities. Moving forward, whether you sample in the spring or fall, the main takeaway is to sample when you have time to do a good job and to make sure you do it at the same time every year to maximize your consistency.
The reliability of a soil test is only as good as the sample you submit. Some helpful tips include:
- Use a grid/zig-zag pattern, draw a map and label where your samples were taken.
- 10–15 cores per sample for every 2.5 acres.
- As far as depth is concerned, use 6–8 inches in tilled soil and 3–4 inches in no-tilled ground.