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Impacts of 22-year organic and inorganic N managements on soil organic C fractions in a maize field, northeast China

Lou, Yilai, Wang, Jingkuan, Liang, Wenju
Catena 2011 v.87 no.3 pp. 386-390
Zea mays, carbon, carbon sequestration, corn, cropping systems, field experimentation, grain yield, microbial biomass, nitrogen fertilizers, potassium permanganate, soil, soil organic carbon, soil productivity, surface storage, China
Impacts of 22-year organic and inorganic N managements on total organic carbon (TOC), water-soluble organic C (WSOC), microbial biomass C (MBC), particulate organic C (POC) and KMnO₄ oxidized organic C (KMnO₄-C) concentrations, C management index (CMI), and C storage in surface soil (0–20cm) were investigated in a maize (Zea may L.) field experiment, Northeast China. The treatments included, CK: unfertilized control, M: organic manure (135kgNha⁻¹year⁻¹), N: inorganic N fertilizer (135kgNha⁻¹year⁻¹) and MN: combination of organic manure (67.5kgNha⁻¹year⁻¹) and inorganic N fertilizer (67.5kgNha⁻¹year⁻¹). TOC concentration and C storage were significantly increased under the M and MN treatments, but not under the inorganic N treatment. The organic treatments of M and MN were more effective in increasing WSOC, MBC, POC and KMnO₄-C concentrations and CMI than the N treatment. The M treatment was most effective for sequestrating SOC (10.6Mgha⁻¹) and showed similar increase in degree of grain yield to the N and MN treatments, therefore it could be the best option for improving soil productivity and C storage in the maize cropping system.