Efficient Use Of N-Fertilizers Under Flooded And Unfglooded Conditions Using N-15

This Investigation aim to study the effect of N-fertilizers at different rates, , and methods of application on wheat plants using 15N-labelled urea .Also , the compined effect of some organic amendments and inorganic N-fertilizer on rice yield using 15 N-labelled urea was investigated. In addituion , thee efficiency of N-fertilizer was also studied under the effect of urease and nitrification inhibitors under laboratory conditions.