Increasing organic matter can reduce soil compaction in sugarbeets
Low organic matter and lack of actively growing roots will increase soil compaction, reduce water infiltration and root diseases in sugarbeets.
Soil compaction in sugarbeet fields has been an ongoing problem for years. The use of heavy farm equipment can create compaction into the subsoil. Beet fields that are compacted will exhibit slow water infiltration, sprangled roots and, often, an increase of root diseases such as Rhizoctonia or Aphanomycetes. Compaction issues will be increased if tillage or harvest is performed under wet soil conditions. Traditional approaches to minimize compaction have been the utilization of subsoilers operated at depths up to 18 inches. The effects of subsoiling have generally increased yields, but can be temporary as equipment re-compact the fields. Increasing organic matter can be a long-term approach to reduce the effects of soil compaction.
It has been estimated that cultivation in the last 100 years has reduced organic matter up to 60 percent. Low organic matter levels will make the soil more susceptible to soil compaction and reduce water infiltration. To increase water infiltration, many growers have increased tiling efforts by narrowing spacing. In conjunction with this, growers will want to increase organic matter content. Organic matter on the surface will cushion the effect of soil compaction. Subsurface organic matter attaches to soil particles and binds soil aggregates, thus reducing compaction and increasing water infiltration.
Building soil organic matter is a long-term process that can include the use of diverse rotations, cover crops and manures. Plant roots create voids and macropores in the soil so that air and water can move through the soil profile. Rotations that include wheat and a cover crop such as clover are extremely beneficial. Oil seed radish cover crops have become very common in the Saginaw Valley and are known for their fast growth and deep rooting capabilities. By lengthening the time of actively growing roots in a crop rotation, growers will help minimize compaction and improve soil health. Be aware in a typical corn-soybean rotation, active roots are only present a third of the time. Adding cover crops between these crops increases the presence of active roots to 80 to 90 percent of the time.
On a short-term basis to minimize compaction, sugarbeet growers should look at conservation tillage, reducing secondary tillage and controlled traffic. Two tillage systems that seem to minimize equipment compaction are strip tillage and stale seedbed planting of beets. We are seeing both being used effectively. Minimizing soil compaction and building organic matter is a long-term process.