Abstract:A 1-year Lysimeter experiment was conducted to study the effect of different N-release rates of polyolefin-coated urea(POCU) and common urea(U) at different application rates on development of wheat and maize and N losses in a wheat-maize rotation at Changping,Beijing.The results showed that N uptake,N use efficiency and maize yield were higher at POCU plots than at U plots during maize seasons.The residual N in soil with POCU after wheat harvest was higher than that of U.The N use efficiency for maize was higher than that for wheat.N application rates between 100 kg/ha and 225 kg/ha per crop did not significantly affect inorganic nitrogen leaching losses.The total amount of leached inorganic N accounted for 0.43%1.12% of N applied(nitrate accounted for 98% of the leached N).These results indicate that leaching was not the major path of N losses under the environmental conditions of the test site.