PLANT GROWTH ON SOILS MIXED WITH DREDGED LAKE SEDIMENT

摘要

Sediment dredged from a fresh-water lake in South Dakota was mixed in various dry volume ratios with either an agriculturally productive soil sand. The effect on the growth and nutrient uptake was determined under greenhouse conditions for three field crops, maize (Zea mays L.), soybean (Glycine max L.), and sunflower (Helianthus anus L.), and tow forage species, alfalfa (Medicago staiva L.) and big bluestem (Andropogon gerardii Vitman). Plant growth measured as shoot dry matter, shoot total N, P, and K concentration, and relative shoot N, P, and K uptake were not diminished for any crop when the dry volume of the dredge material mixed with the Moody soil increased from 25/100 to 100/100. However, shoot dry matter, shoot N, P, and K concentration, and relative N, P, and K uptake increased dramatically as increasingly greater proportions of the dredge material were mixed with sand. The dredged lake-bottom sediment could be applied appropriately to an agricultural soil for land disposal without impairing plant growth. In addition, when dredge material was mixed with a lighter textured soil, productivity was greatly enhanced. The favorable chemical and physical properties of the dredge material probably improved water and nutrient retention of the soil mix when added to an unbuffered sand medium.