The Midwest has recently experienced a massive blast of cold weather from the north the week of November 11. Fortunately, warmer weather has returned, harvest is finishing up and field work has been getting done in many areas. Getting the discing, strip tilling, and ripping done is a good feeling but when the equipment is back in the shed for the year we need to get one more project completed - soil sampling! There are a few ways to manage soil sampling depending on how much you want to invest and how much time you have before winter sets in and the ground freezes. The two best options would be to do it yourself based on management zones or hire someone to grid sample.
You can either hire someone to collect soil samples or you can do it yourself. If you are well acquainted with a particular piece of dirt, you can save yourself some money and get quality soil samples yourself. All you need is a shovel, bucket, paper lunch bags, and a pen. For example, a grower that has been farming a particular farm for many years and is well aware of areas in the field which are excellent, fair, and poor (sloped, level, rocky, fertile, drained, wet, etc.) These are called management units. This farmer has established 5 management units (3 to 6 recommended) on this field because of previous knowledge of his farm. The farmer takes 15 random soil samples to a depth of 8 inches in one management unit with his shovel, mixes them together in his bucket, then labels and fills one paper bag with that soil sample. This process is duplicated across all management units, and bags are then sent to the nearest laboratory for analysis and fertilizer recommendation.
For more precise soil samples, grid sampling can be done to provide better information on soil variability throughout a field. Many growers are reluctant to spend many hours getting down and dirty in a field to grid sample the entire field with 1-acre samples. Who can blame them as this is a tedious process which requires an elaborate computer program, a handheld GPS unit, and pulling many soil cores which a farmer would rather let an agronomist do. Grid sampling done for optimum accuracy includes 1-acre samples, 2.5-acre samples are acceptable, and 4-acre grid samples are done at more economical prices with reasonable results. When a grid sample is done, 5-8 core samples should be pulled at 6-8 inches per sample. This data can provide a good map for many years; 10 – 20 years for organic matter and CEC; 5 – 10 years for pH; and 5 years for P, K, and Zinc. Include these grid samples into a GPS unit, along with previous years yield data, to create a precise fertilization and planting population program to maximize yield and efficiency on a farm.
The way you get the sample isn’t near as important as getting the sample. Soil samples will let us know what nutrients we are short on including Phosphorus, Zinc, Sulfur, Potassium, and many more depending on where your farm is located. Soil samples will also tell us pH so we know whether or not lime is needed to correct low pH issues. Get your soil sampling done while the weather is nice and spend the cold winter months coming up with a fertilizer plan to maximize profitability next summer with Hoegemeyer products. Contact your local Hoegemeyer DSM or Agronomist with any questions.
-Craig Langemeier, Western Product Agronomist