Fall soil management practices
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
Fall is the time of year when harvesting activities are beginning to wind down, but it should also be the time to reflect on the past year and begin planning for next year. The following is a brief listing of items to consider.
Soil sample. Many of the vegetable crops utilize large amounts of nutrients, especially potassium. Soil sampling and testing in the fall provides the opportunity to apply lime where needed and to determine fertilizer needs for the next year, and possibly fertilizer purchases prior to the end of the year. Liming where needed provides an excellent return on investment.
Remember and locate those areas in fields where plant growth was not as good as the rest of the field. Soil sample and test those areas separate from the rest of the field. This will let you know if the poor plant growth was related to an improper soil pH or lack of one of the nutrients. Special application to these areas may be necessary.
Chisel or subsoil fields or areas of fields where compaction may be suspected. There is no benefit from subsoiling more than two inches below the zone of compaction. The zone of compaction frequently occurs in the top 12 inches. The zone or depth of compaction may be identified by using a tile rod or soil probe when there is good soil moisture. Compaction is indicated by resistance in pushing the rod into the ground. Probe the soil in several different spots in a field to determine whether not compaction is a concern or the depth of compaction. Also, check the soil moisture at the depth of subsoiling. The soil should break apart when handled and not stick together in a clump when squeezed. If the soil is too wet, subsoiling will not be of benefit. The shanks should shatter the soil and not create a smeared channel.
Seed a winter cover crop. At this time of year seeding the winter cereal grains, barley, wheat or rye, will give good vegetative growth to sequester residual nutrients, especially nitrogen, and vegetative cover to minimize wind and water erosion during the winter and early spring months.
Fall nutrient application. Some farmers apply nutrients in the fall in preparation for next year’s crops, but care needs to be exercised in making this decision. Fall application of potassium is satisfactory on loam and clay loam soils, but on sandy soils with a cation exchange capacity (CEC) less than 6 me/100 gram significant loss of potassium by leaching can occur. Therefore, on soils with a CEC of less than 6 fall potassium application is discouraged. Fall application of nitrogen (N) is generally not encouraged. If fall N is applied, it should be done after the soil temperature at two inches is below 50°F and a nitrification inhibitor should be added to the N fertilizer. Anhydrous ammonia is the preferred material to apply in the fall. Fall N application on sandy soils with a CEC less than 6 is definitely discouraged because of the greater risk of N leaching loss. Much of the K and N leaching loss occurs in late winter and early spring when saturated soils are draining from snow melt and spring rains.