Soil Sampling: A Little Investment for a Lot of Information
Fall is the ideal time for Mississippi soybean farmers to test their soil. Below, Mississippi State University (MSU) research specialist Bobby Golden, Ph.D., explains why soil testing is so important for farmer success and how it can help farmers prepare for next year’s growing season.
Q: Why is it important for farmers to test their soil after harvest?
A: Soil testing is the first step in maintaining a high-yield environment. Without adequate soil nutrients, high-yielding soybeans are unachievable. Soil testing is especially important moving into 2017. Many Mississippi farmers applied a lower rate of soil-applied nutrients last fall and spring because commodity prices were low. We have received numerous calls about nutrient-deficient soybean in 2016 that could have been avoided with adequate soil-test-based fertilization.
Q: How does yield affect soil nutrients?
A: Yield and soil nutrients are closely related. Soil nutrients are like gasoline in a truck. The more gas you have, the farther you can drive. Likewise, nutrients at the optimum level will allow soybeans a good base for high yield. You wouldn’t take a trip to Texas with a quarter-tank of gas, so let’s not try to grow soybeans and expect high yield with only a quarter of the necessary nutrients.
Q: Do you have any recommendations for farmers looking to test their soils?
A: There are numerous avenues for a farmer looking to test their soils for the first time or to begin a more regularly scheduled soil-testing program. If a farmer has never soil tested, I would suggest starting on a three-year cycle, taking samples in the fall after the same crop in the rotation cycle. For the farmer looking for precision, and really wanting to understand what’s going on, we could discuss soil testing every other year to build up a database of nutrient-removal trends on their farm more rapidly. One confusion around soil testing is that a soil-test recommendation is for three years, and the recommendation only gets applied once. The truth is, when a farmer receives that soil-test information, that recommendation should be applied every year until the next soil test is taken.
Q: What should farmers look for after receiving the results of the testing?
A: Trends over time. If your current fertilization plan is not meeting your current yield aspirations or if you see a declining soil-test level, your fertilization plan may need to be altered. Multiple years of soil-testing data will allow farmers to tweak a university or private lab’s recommendations based on what’s happening on their operation. As always, if farmers are uneasy about the cost associated with fertilization or with altering a recommendation to fit their needs, I’m a phone call away and would be glad to sit down and discuss how to move forward.
Q: Do you have recommendations for farmers looking to improve the quality of their soil?
A: The first step to improving soil quality would be to take regularly scheduled soil tests. Proper lime and nutrition go a long way to helping achieve better soil quality. The next step would be to not burn or bale corn stubble that may be grown in rotation with soybeans. If we start with these two items, we will go a long way to improving our soils. Once we have the basics down, we can move on to other avenues in helping increase the quality of our soil.