Soil Compaction

The weather is finally starting to feel like fall after the warm stretch we had in September. As you start to combine, plan ahead to avoid driving on fields when they are still wet from any rain events that we will receive. Unseen by our eyes, soil compaction can be a key factor in the decreased productivity in some fields. A healthy soil in our area will be about half solid material and half pore space. Soil organic matter and soil minerals make up the solid portion of soil while air and water should be split between the total pore space. Normally, water would infiltrate the soil profile and pass through the soil pores until the excess water has drained away and the soil has returned to its water holding capacity. Compacting the soil reduces the amount pore space in soil which can lead to ponding in fields from reduced infiltration. Poor water infiltration will also cause most of the soil pore space remaining to be taken up by water with little room for air. The plant roots won’t get the oxygen they need so they start to suffocate which is one cause of the short, yellow plants we observe. Anytime we drive on soil we are causing some compaction so we can never eliminate it entirely but there are ways that we can try to reduce soil compaction. Attempt to reduce axel load on soil by only using the horsepower you need to per-form each field operation. Avoid excessive tire pressures and inflate tires to what the manufacturer recommends. Waiting until fields have dried out will reduce the compaction done to a field. Con-trolled traffic limits soil compaction to only the areas you need to drive on for each field operation. Taproot crops penetrate deep into the soil and break up some of the compaction that we cause. The research on the positive effects of subsoiling is generally inconclusive so that is an area to look at more in depth before you try it on your farm. Soil compaction causes more problems and has more solutions than the ones I have mentioned but these are some ideas to get you thinking in the right direction. Like with many problems, it is better to be proactive rather than reactive when it comes to soil compaction.