title: [Effects of nitrogen application rate and its basal-/top-dressing ratio on spatio-temporal variations of soil NO3- -N and NH4+ -N contents].
abstract: Under high-yielding cultivation condition, this paper studied the spatiotemporal variations of soil NO3 -N and NH4+ -N contents as affected by different nitrogen application rate and its basal-/top-dressing ratio, and calculated the apparent budget of soil nitrogen at different growth stages of wheat. The results indicated that compared with split application, applying all fertilizer nitrogen at jointing stage decreased the soil NO3- -N content and apparent surplus of soil nitrogen before jointing stage, and decreased the nitrogen leaching to deeper soil layers. Applying fertilizer nitrogen at flagging stage had no significant difference with split application in soil NO3- -N content, but increased soil NH4+ -N content. Applying fertilizer nitrogen at maturing stage increased the soil NO3- -N content in 0-60 cm and 0-20 cm layers. In comparing with applying 240 kg x hm(-2) of fertilizer nitrogen at jointing stage, applying 168 kg x hm(-2) of fertilizer nitrogen at the same stage decreased the soil NO3- -N and NH4+ -N contents at flagging stage, soil nitrogen deficit from flagging to maturing stage, and soil NO3- -N content at maturing stage. The grain yield and its protein content had no significant difference among different treatments, but applying all 168 kg x hm(-2) fertilizer nitrogen at jointing stage induced the highest grain protein content.
authors.affiliation: Key Laboratory of Wheat Physiology and Genetics Improvement of Agriculture Ministry, Shandong Agricultural University, Taian 271018, China. sdaun041@sdau.edu.cn
authors.forename: Xinghua
authors.initials: X
authors.lastname: Ma
authors.forename: Zhenwen
authors.initials: Z
authors.lastname: Yu
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Liang
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
authors.forename: Guiping
authors.initials: G
authors.lastname: Shi
mesh_terms: D005308:Fertilizers; D009566:Nitrates / Q000032:analysis*; D009584:Nitrogen / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000032:analysis*; D012987:Soil / Q000032:analysis*; D014908:Triticum / Q000254:growth & development
chemical_list: D005308:Fertilizers; D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D012987:Soil; D009584:Nitrogen