title: Carbon and Nitrogen Mineralization in Relation to Soil Particle-Size Fractions after 32 Years of Chemical and Manure Application in a Continuous Maize Cropping System.
abstract: Long-term manure application is recognized as an efficient management practice to enhance soil organic carbon (SOC) accumulation and nitrogen (N) mineralization capacity. A field study was established in 1979 to understand the impact of long-term manure and/or chemical fertilizer application on soil fertility in a continuous maize cropping system. Soil samples were collected from field plots in 2012 from 9 fertilization treatments (M0CK, M0N, M0NPK, M30CK, M30N, M30NPK, M60CK, M60N, and M60NPK) where M0, M30, and M60 refer to manure applied at rates of 0, 30, and 60 t ha(-1) yr(-1), respectively; CK indicates no fertilizer; N and NPK refer to chemical fertilizer in the forms of either N or N plus phosphorus (P) and potassium (K). Soils were separated into three particle-size fractions (2000-250, 250-53, and <53 μm) by dry- and wet-sieving. A laboratory incubation study of these separated particle-size fractions was used to evaluate the effect of long-term manure, in combination with/without chemical fertilization application, on the accumulation and mineralization of SOC and total N in each fraction. Results showed that long-term manure application significantly increased SOC and total N content and enhanced C and N mineralization in the three particle-size fractions. The content of SOC and total N followed the order 2000-250 μm > 250-53 μm > 53 μm fraction, whereas the amount of C and N mineralization followed the reverse order. In the <53 μm fraction, the M60NPK treatment significantly increased the amount of C and N mineralized (7.0 and 10.1 times, respectively) compared to the M0CK treatment. Long-term manure application, especially when combined with chemical fertilizers, resulted in increased soil microbial biomass C and N, and a decreased microbial metabolic quotient. Consequently, long-term manure fertilization was beneficial to both soil C and N turnover and microbial activity, and had significant effect on the microbial metabolic quotient.
authors.affiliation: National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Andong
authors.initials: A
authors.lastname: Cai
authors.affiliation: College of Agriculture, Guizhou Universities, Guiyang 550025, China.
authors.forename: Hu
authors.initials: H
authors.lastname: Xu
authors.affiliation: National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Xingfang
authors.initials: X
authors.lastname: Shao
authors.affiliation: Jilin Academy of Agricultural Sciences, Gongzhuling 136100, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
authors.affiliation: National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Wenju
authors.initials: W
authors.lastname: Zhang
authors.affiliation: National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Minggang
authors.initials: M
authors.lastname: Xu
authors.affiliation: Soil Biology and Molecular Ecology Group, School of Geography and Environmental Sciences, Institute of Agriculture, University of Western Australia, Crawley, WA 6009, Australia.
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Murphy
mesh_terms: D018533:Biomass; D002244:Carbon / Q000737:chemistry / Q000378:metabolism*; D008372:Manure / Q000382:microbiology; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D010316:Particle Size; D010758:Phosphorus / Q000737:chemistry / Q000378:metabolism; D011188:Potassium / Q000737:chemistry / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D003313:Zea mays / Q000254:growth & development / Q000378:metabolism*
chemical_list: D008372:Manure; D012987:Soil; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen; D011188:Potassium