Nitrogen transformation in maize soil after application of different organic manures

摘要

The nitrogen transformation in maize soil after application of different organic manure was studied. The nitrogen mineralization in surface soil, NO_3~- -N dynamics and distribution in soil profile, and N_2O emission were investigated. Eight treatments were laid out randomizing with three replications in 24 plots: maize plantation without fertilized CK1), bare soil without maize plantation and fertilization (CK2), swine manure(S1, S2), poultry manure(P1, P2), and cattle manure(C1, C2). Three manures were applied at two application levels(15 t/hm~2 and 30 t/hm~2). The results indicated that NH4* -N in surface soil showed the same temporal pattern without much variation among different treatments. But NO_3~- -N in the same layer exhibited large temporal pattern in all treatments, which was mainly due to its easy eluviations of NO_3~- -N in soil, its transformation to N_2O and the influence of precipitation. The distribution of NO_3~- -N in the soil profile during maize growing season showed the leaching tendency from surface soil to subsoil, which was different among the treatments. The poultry treatments showed the largest leaching tendency. The study also revealed that the emissions of N2 O were affected by the application of organic manures in the order of P2 > S2 > C2 > PI > S1 > C1 > CK1 > CK2. All these results showed that organic manure applications significantly affect nitrogen transformation and distribution in maize soil. Considering N_2O emission and NO_3~- -N leaching, the management of organic manure in the agriculture needs further studies.