Peat and Muck Drainage Problems

Drainage of organic soils results in lowering of the surface (subsidence) by shrinkage due to drying, loss of the bouyant force of groundwater, compaction, wind erosion, burning, and biochemical oxidation. The relative effect of each of these factors depends on soil origin, land-management practices, and climate. The total subsidence rate is proportionate to depth of drainage—the lower the water table, the greater the soil loss. In the Florida Everglades the largest losses have been due to biochemical oxidation. With continued subsidence these organic soils will be too shallow for agriculture by the year 2000. Here, drainage has permitted sea water to move inland to contaminate the Biscayne aquifer, and has also changed the original ecology of the Everglades area to the detriment of wildlife. Recent water-management programs (1945-68) have ameliorated the consequences of overdrainage. Subsidence of organic soils with drainage occurs worldwide with observed rates up to 3 inches annually. To obtain maximum use of organic soils, drain only those lands that are potentially arable, place drained lands into productive use quickly, and hold water tales as high as crop and human requirements permit.