title: [Nitrogen cycling in rice-duck mutual ecosystem during double cropping rice growth season].
abstract: Raising duck in paddy rice field is an evolution of Chinese traditional agriculture. In May-October 2010, a field experiment was conducted in a double cropping rice region of Hunan Province, South-central China to study the nitrogen (N) cycling in rice-duck mutual ecosystem during early rice and late rice growth periods, taking a conventional paddy rice field as the control. Input-output analysis method was adopted. The N output in the early rice-duck mutual ecosystem was 239.5 kg x hm(-2), in which, 12.77 kg x hm(-2) were from ducks, and the N output in the late rice-duck mutual ecosystem was 338.7 kg x hm(-2), in which, 23.35 kg x hm(-2) were from ducks. At the present N input level, there existed soil N deficit during the growth seasons of both early rice and late rice. The N input from duck sub-system was mainly from the feed N, and the cycling rate of the duck feces N recycled within the system was 2.5% during early rice growth season and 3.5% during late rice growth season. After late rice harvested, the soil N sequestration was 178.6 kg x hm(-2).
authors.affiliation: Circular Agriculture Research Center, China Agricultural University, Beijing, China. zhangfan898@sina.com
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.forename: Yuan-Quan
authors.initials: YQ
authors.lastname: Chen
authors.forename: Peng
authors.initials: P
authors.lastname: Sui
authors.forename: Wang-Sheng
authors.initials: WS
authors.lastname: Gao
mesh_terms: D000383:Agriculture / Q000379:methods*; D000818:Animals; D004372:Ducks / Q000254:growth & development*; D017753:Ecosystem; D009584:Nitrogen / Q000032:analysis; D058458:Nitrogen Cycle / Q000502:physiology*; D012275:Oryza / Q000254:growth & development*; D012621:Seasons; D012987:Soil / Q000032:analysis
chemical_list: D012987:Soil; D009584:Nitrogen