title: [Effects of nitrogen regulators on fertilizer nitrogen transformation in meadow cinnamon soil and on pakchoi growth].
abstract: Soil incubation test and pot experiment were conducted to investigate the effects of dicyandiamide (DCD) and its combination with nano-carbon on the transformation of fertilizers (urea and ammonium bicarbonate) nitrogen (N) in meadow cinnamon soil, a typical soil type in North China Plain, and on the growth of pakchoi (Brassica chinensis). In the first two weeks after applying urea and ammonium bicarbonate, the soil NH4+-N and NO3(-)-N contents varied greatly, but little variation was observed since then. The effects of the applied fertilizer N on the pakchoi growth and its N use efficiency differed significantly at early growth stages, but had little difference at harvesting stage. The DCD inhibited the transformation of the fertilizer N (especially ammonium bicarbonate N) into nitrate markedly, and this effect increased with increasing DCD dose. Under the conditions of our experiment, the optimal application rate of DCD was 1.0-1.5% of applied fertilize N, which could increase the pakchoi yield significantly, improve the leaf color, decrease the plant nitrate contents, and increase the fertilizer N use efficiency. The combination of DCD and nano-carbon exerted a synergistic effect on inhibiting soil ammonium oxidation, and also, promoted the pakchoi growth and N utilization at early growth stages significantly and decreased the plant nitrate level at harvesting stage.
authors.affiliation: College of Resource and Environmental Science, Hebei Agricultural University, Baoding 071001, Hebei, China. sunzhm2002@yahoo.com.cn
authors.forename: Zhi-Mei
authors.initials: ZM
authors.lastname: Sun
authors.forename: Kuo
authors.initials: K
authors.lastname: Zhang
authors.forename: Jian-Tao
authors.initials: JT
authors.lastname: Liu
authors.forename: Huan-Sen
authors.initials: HS
authors.lastname: Si
authors.forename: Yan-Qun
authors.initials: YQ
authors.lastname: Wang
mesh_terms: D029741:Brassica rapa / Q000254:growth & development* / Q000378:metabolism; D002244:Carbon / Q000494:pharmacology; D005308:Fertilizers; D006146:Guanidines / Q000494:pharmacology*; D053758:Nanoparticles; D009584:Nitrogen / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D014508:Urea
chemical_list: D005308:Fertilizers; D006146:Guanidines; D012987:Soil; D002244:Carbon; D014508:Urea; C004711:dicyandiamido; D009584:Nitrogen