Two field experiments were carried out at El-Khroub experimental station, east of Constantine, Algeria, to evaluate the effect of N, P, K fertilization and their interaction on growth characters and yield of wheat grown on calcareous soil. The design of each experiment was split-split plot. Urea was applied as folier application to one experiment to evaluate the supplementel application of nitrogen under dry farming conditions. The results showed that the main stem height, number and height  of tillers and number of leaves were varried according to the levels  of  N, P, K fertilization as well as to presence or absence of urea., Straw yield significantly increased due to increasing nitrogen level and potassium fertilization in absence or presence of urea. However, grain yield was significantly increased either with increasing nitrogen level in absence of urea or with increasing phosphorus levels in absence or presence of urea. Straw yield was significantly affected by N * P interaction in absence or presence of urea and N * P * K when urea was applied. However, grain yield was significantly affected by N * P and N * P * K interractions in absence of urea application.

Application of urea to agricultural soil may pollute the air environment due to ammonia (NH3) volatilization. Zeolite, Humate, biocher and biofertilizer may be used to control N losses resulting from urea transformation to NH3. A laboratory soil incubation experiment was conducted to determine the effects of zeolite, K-humate, biocher and biofertilizer on controlling NH3 losses out of applied urea. Calcareous soil sample from El-Nobaria area, Beheira Governorate was treated with different amendments and incubated under laboratory condition for 13 weeks. Results obtained showed that soil treated with urea in the presence of different amendments significantly reduced NH3 release from urea as compared to the control. During the first 80 days of the incubation ammonia losses were highest in control compared to soil treated with the different amendments. Biocher treatment showed the highest effect in reducing ammonia volatilization from calcareous soil. Therefore, treating calcareous soil with biocher and biofertilizer can decrease were losses as ammonia and increase nitrogen availability in soil, and hence reduces air pollution by ammonia.