title: Effects of biochar and maize straw on the short-term carbon and nitrogen dynamics in a cultivated silty loam in China.
abstract: Application of maize straw and biochar can potentially improve soil fertility and sequester carbon (C) in the soil, but little information is available about the effects of maize straw and biochar on the mineralization of soil C and nitrogen (N). We conducted a laboratory incubation experiment with five treatments of a cultivated silty loam, biochar produced from maize straw and/or maize straw: soil only (control), soil + 1 % maize straw (S), soil + 4 % biochar (B1), soil + 4 % biochar + 1 % maize straw (B1S), and soil + 8 % biochar + 1 % maize straw (B2S). CO2emissions, soil organic C, dissolved organic C, easily oxidized C, total N, mineral N, net N mineralization, and microbial biomass C and N of three replicates were measured periodically during the 60-day incubation using destructive sampling method. C mineralization was highest in treatment S, followed by B2S, B1S, the control, and B1. Total net CO2emissions suggested that negative or positive priming effect may occur between the biochar and straw according to the biochar addition rate, and biochar mineralization was minimal. By day 35, maize straw, irrespective of the rate of biochar addition, significantly increased microbial biomass C and N but decreased dissolved organic N. Biochar alone, however, had no significant effect on either microbial biomass C or N but decreased dissolved organic N. Mixing the soil with biochar and/or straw significantly increased soil organic C, easily oxidized C and total N contents, and decreased dissolved organic N content. Dissolved organic C contents showed mixed results. Notably, N was immobilized in soil mixed with straw and/or biochar, but the effect was stronger for soil mixed with straw, which may cause N deficiency for plant growth. The application of biochar and maize straw can thus affect soil C and N cycles, and the appropriate proportion of biochar and maize straw need further studies to increase C sequestration.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, 712100, China.|College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China.
authors.forename: Li-Xia
authors.initials: LX
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, 712100, China.|College of Forestry, Northwest A&F University, Yangling, 712100, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, 712100, China. shenyufang@nwsuaf.edu.cn.|College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China. shenyufang@nwsuaf.edu.cn.
authors.forename: Yu-Fang
authors.initials: YF
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, 712100, China. sqli@ms.iswc.ac.cn.|College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China. sqli@ms.iswc.ac.cn.
authors.forename: Shi-Qing
authors.initials: SQ
authors.lastname: Li
mesh_terms: D018533:Biomass; D002244:Carbon / Q000032:analysis*; D057965:Carbon Sequestration; D002606:Charcoal / Q000737:chemistry*; D002681:China; D009584:Nitrogen / Q000032:analysis*; D058458:Nitrogen Cycle; D010084:Oxidation-Reduction; D018547:Plant Stems / Q000737:chemistry* / Q000254:growth & development; D012987:Soil / Q000737:chemistry* / Q000592:standards; D012988:Soil Microbiology; D003313:Zea mays / Q000737:chemistry* / Q000254:growth & development
chemical_list: D012987:Soil; C540010:biochar; D002606:Charcoal; D002244:Carbon; D009584:Nitrogen
keywords: Biochar; Carbon fraction; Maize straw; Mineralization; Nitrogen fraction; Priming effect