Abstract
Urea , sheep manure , and mix (urea + sheep manure ) fertilizers were added to calcareous soil of northern Iraq / Mosul. Soil which classified as calci-camborthids. Fertilizers were added at rate 80 kg N. D-1 for each fertilizers, surface, and subsurface (depth 15cm) application for four season (Spring , Winter, Summur and Autumn) in order to study the effect of type and depth of fertilization and ecologyical conditions on ammonia volatilization. The results indicated that the, urea application produced ahigh ammonia volatilization (19.76, 51.14, 38.82 and 0.34 %)of nitrogen added for surface application during four seasons respectivily, and 3.03, 13.69 ,9.15 and 0.103 of nitrogen added for sub surface application during four season repectivily, while sheep manure record less amount of ammonia volatilization, comparing with urea fertilizer. The amount of ammonia volatilization were (6.66, 7.58, 12.19 and 0.14 %) of nitrogen added for surface application during the four seasons respectivily. Sub surface application of fertilizers reduced the amount of ammonia volatilization and reductive percent were 2.75, 4.66, 6.85 and 0.042% of nitrogen added during the four seasons respectivily .The low in temperature has caused a significate reduction in ammonia volatilization and increasing of temperature caused increase in ammonia loss.
