College of Agriculture University of Al-Qadisiya


A field experiment is conducted in Al- Muthanna province beside sweer river during the growing season of 2015. The experiment was carried to evaluate the efficiency water extracts of some plants (Caper seeds, carlic ) and urea treated with DMPP on the nitrification inhibition, ,NO3¯-N and NH4+-N concentrations in soil ,Nitrogen uptake, dry matter, seed weight. Plants extracts are applied to at the rate of 1:10 (extract: urea). Conventional urea and urea with extracts and DMPP are applied at the rates of 80 , 160 , 240 Kg N h - 1 at two doses. Factorial Experiment carried out according to RCBD with three replications. Soil samples (at depth 0-30) cm are collected four times 15,30,45 and 60 day during growing season after add it fertilizer. Results of the study could be summarized as: Water extract of caper seeds results in significantly higher nitrification inhibition , nitrogen uptake, dry matter and seed weight than that caused by chemical inhibitor DMPP and urea without inhibitor . Plants fertilized with level 160 Kg N h – 1 as urea amended with kipper plant extract results in a significantly higher than that of plant fertilized with all treatments than level 240 Kg N h – 1..