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Abstract
ABSTRACT
Two incubation experiments as well as pot and field trails were conducted to study the effect of some chemical nitrification and urease inhibitors and some organic amendments on the transformation of ammoniurn sulphate and urea in the soil under North Sinai conditions.
In the first incubation experiment, chemical nitrification inhibitors as dicyandiamide and 2,5dichloroaniline were used at the rates of 0, 2.5, 5, 7.5 and 10% from nitrogen added with both ammonium sulphate and urea fertilizers application. Barley straw and chicken manure were used as soil organic amendments with rates ofO, 0.05, 0.1, 0.15 and 0.2 g kg1 soil.
in separate experiment urease inhibitors N-(n-butyl) thiophosphoric tn ami de, phosphoric triamide. phenyiphosphoryl diamidate and thiophosphoryl diamidate were used at the rates of 0.0, 2.5, 5, 7.5 and 10% from nitrogen applied in the form of urea. Both previous experiments were conducted using plastic column having 60 cm height and 10 cm diameter which packed with the soil at the rate of 5 kg column1. Nitrogen was added at the rate of 2500 mg N colurnn’. Soil moisture content was maintained at 60% from water holding capacity for 8 weeks then raised to 110% from water holding capacity during two weeks in order to obtain the soil leachate. Studied columns were incubated under room temperature. Soil samples were taken after cutting the columns to three depths (0-10, 10-30 and 30-50cm). nitrate, nitrite, ammonium and urea were determined in the soil samples at 0, 1, 2, 4, 6 and 8 weeks of experimental period as ve1l as in the soil leachate.