Keeping muck soils sustainable
Muck soils are an economically important, non-renewable resource for Michigan agriculture. Satisfactory soil conservation and nutrient management practices are needed to sustain these soils for future crop production.
The Michigan State University Extension Soil Academy 2012 participants had thoughts of prehistoric times when they toured the Kunkle’s Muck Vegetable Farm on September 5 in Eaton Rapids, Mich. They witnessed the results of a transformation of what was once a big lake or swamp into what is now a productive farm rich in black, organic soil. These soils, referred to as Histosols (from Greek histos, "tissue"), are typically found in low lying areas with high water tables and restricted drainage. Under anaerobic conditions, the rate of decomposition of plant remains (primarily sedges and mosses) is very slow. It takes nature about 500 years to accumulate 30 cm of organic soil.
Based on the level of decomposition, these soils are classified either as peat (slightly decomposed organic material) or muck (highly decomposed organic material). In Michigan, muck soils are found scattered in the Upper and Lower Peninsula. Globally, these soils occupy about 1.2 percent of the ice-free land area.
Organic soils have a major chronic problem – they subside or sink at a steady rate. When intensively cropped, muck soil subsides at a rate of about 30 cm every 10 years, becoming progressively shallower. This is due to the oxidation of the organic matter coupled with wind and soil erosion.
Darryl Warncke, MSU
Department of Plant, Soil and Microbial Sciences,
speaks to the Soil
Considerable investment and skill are needed to develop and maintain muck soils for crop production. An obvious requirement is to improve drainage by using tile, dikes, ditches and pumps. Once drained, the muck soils are ideal for raising high quality specialty crops such as carrots, onions, radishes, lettuces, potatoes and mint. The dark color warms the soil faster and soil particles have low bulk density, helping root crops grow and mature faster.
The Kunkle Farm is well known for its high quality onions. To combat wind and soil erosion, wind breaks and ground covers are needed to protect the top soil. The sod industry of Michigan relies heavily on muck soils. Because the muck is organic and not mineral, "peeling" the turf off and rolling it up into rolls for shipment is much easier.
Muck soils differ greatly from mineral soils not just in their origin, but also in nutrient management. Darryl Warncke, professor emeritus at Michigan State University and one of the very few experts in muck farm agriculture, addressed participants and highlighted some of the major differences in relation to soil pH, nitrogen, phosphorus, potassium and micronutrient management. In contrast to mineral soils, maintaining a pH level around 5.5 is satisfactory for most muck crops. Muck soils are rich in nitrogen and on the average nitrogen recommendation is 60 pounds per acre less than the recommendation on mineral soils. Muck soils are naturally low in boron, copper, manganese and zinc. A soil test is a valuable tool to determine the need for annual applications.
Additional information on muck farming
- Improving productivity of onions grown on muck with mustard cover crops in Michigan, Mathieu Ngouajio, MSU
- Nutrient-rich muck makes perfect soil for crops in Central New York, Debra J. Groom, The Post-Standard