Inorganic Nitrogen and Soluble Salts in a Davidson Clay Loam used for Poultry Manure Disposal
1979
Weil, R. R. | Kroontje, W. | Jones, G. D.
The logistics of handling poultry manure often dictate that it be spread on land near to its source at rates far in excess of what would constitute its efficient use as fertilizer. This study measured, at various times during the growing season, the concentrations of soluble salts, ammonium, nitrates, and nitrites in the upper horizons of a common Piedmont soil which had received yearly up to 100 metric tons of poultry manure per ha for 5 years. During spring and summer, concentrations of soluble salts (up to 4,064 ppm) and nitrite-N (up to 60 ppm) were high enough to be toxic to corn (Zea mays, L. cultivar Pioneer 3369A). Ammonium-N was detected at up to 800 ppm in April, but decreased to less than 100 ppm by July. Both stand establishment and subsequent growth of corn were very poor on the heavily manured plots. As seedlings, corn plants on these plots exhibited burned leaf tips and margins and stunted root growth associated with high levels of ammonia, nitrites, and total soluble salts. Severe moisture stress was evident throughout the growing season due to the effects of salinity and stunted root systems. Rapid leaching of salts and nitrates did not take place until after September. Denitrification appeared to be responsible for some losses of nitrates. Despite the accumulation of nitrites, especially in May and July, most probable number determinations failed to show any consistent inhibition of the populations of Nitrosomonas and Nitrobacter.
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