Urease activity in soils subjected to flooding and its effect on nitrogen uptake by corn and wheat
1998
Eivazi, F.
The flooding during the summer of 1993 in the Midwestern United States, particularly in the floodplains of the Mississippi and Missouri rivers, left many fields covered with sand and silt deposits of varying depths. Sand deposits, especially those greater than 10 cm deep, significantly decreased the productivity of soils in the floodplains. These soils are typically among the most productive soils in the Midwest. The development of management techniques for regaining the productivity of these soils following floods is of particular concern. The objectives of this study were to determine the effects of flooding and drying on urease activity, and to obtain information useful in recommending sources and rates of nitrogen (N) for corn and wheat production on these soils. A greenhouse experiment was conducted with a Waldron silty clay (Aeric Fluvaquents) soil collected from three locations within the flooded area with deposits ranging from less than 10 cm to 40 cm deep. There was a significant decrease in urease activity due to flooding compared to pre-flood level and the urease activity was inversely correlated with the amount of sediment deposited. There was no significant difference in dry matter yield of corn and wheat grown in soil (with no sand/silt deposit) when treated with urea or ammonium nitrate. Moldboard deep plowing to mix the buried soil with flood deposits proved to be beneficial in restoring productivity of the flood-damaged lands. The results of this study indicated that for immediate cropping in flooded agricultural lands, ammonium nitrate may be more beneficial than urea.
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