羊草草地植被－土壤系统氮循环研究

	羊草草地植被－土壤系统氮循环研究
	李玉中; 王庆锁; 钟秀丽; 任娜
刊名	植物生态学报
	2003
卷号	27 期号:2 页码:177-182
关键词	羊草草地植被-土壤系统氮循环 N内部循环分室模型草地
ISSN号	1005-264X
其他题名	N internal cycling in leymus chinensis grassland vegetation-soil system
英文摘要	研究表明，0-30cm土层7月氮（N）总储量为479．2g.m^-2，其中主要为有机N，占总N量的98．5％，土壤中的无机N年度变化很大，在2．55-11．3g.m^-2之间，7月无机N储量为7．3g.m^-2，与其它类型草地不同。该类型草地土壤铵态N与硝态N含量有些季节相差不大，有些季节硝态N的含量超过铵态N的含量，铵态N的峰值出现的时间早于硝态N。植物根系吸收利用的无机N约为3.48g.m^-2.a^-1，植物根系向地上每年输送的N量为2．97g.m^-2.a^-1，地上活体向地下转移的N量为1.54g.m^-2.a^-1，植物地上部分每年转为立估凋落物的N量为1.43g.m^-2.a^-1，由立枯凋落物转为土壤有机N的量大于1.08g.m^-2.a^-1，植物根系每年转为土壤有机N的量为1.51g.m^-2.a^-1。; Objectives of the research were to determine the extent of internal cycling of Nitrogen (N) in Leymus chinensis grasslands using the compartment model method. The internal ecosystem was divided into five compartments: (i) Above-ground N, (ii) Standing dead and litter N, (iii) Living root N, (iv) Soil organic N, and (v) Soil mineral N.Above-ground biomass was harvested from five 1 m × 1 m quadrats in each plot while the underground biomass was collected from 25 cm × 25 cm sections at 30 cm soil depth. The soil samples were washed, and dead roots were separated from living roots. Soil N for total N and mineral N test was sampled at two depths (0-15 cm and 15-30 cm) . The above samples were collected at 4 weeks intervals between mid-April to mid-September with five replications. Standing dead and litter were collected from five 1 m × 1 m quadrats in mid-October, 1994, each 100 g of the samples was put into one nylon net bags, total 30 bags of the samples were randomly scattered on grassland soil surface, and 5 samples were collected every month from mid-April to mid-Sep, in 1995. The remaining samples were weighed and N content was tested for each sample.The total N of plant and soil was measured using Kjeldahl digestion method. The amounts of NH_4~+ -N and NO_3~--N measured by distillation method. The result indicated that the soil-plant system contained 479.2 g·m~(-2) of N, nearly all in the organic form. The plant available N, about 1.5% of total N in the forms of NH_4+ and N0_3~- , the seasonal changes of the two forms were great, the storage of soil mineral compartment was between 2.55-11.3 g·m~(-2), and the content of NQ_3~- -N was even higher than NH_4~+ -N, which is different from the other type grasslands, where the peak of NH_4~+ -N contents appeared earlier than that of NQ_3~- -N contents. Plant root uptook N 3.48 g·m~(-2)a~(-1), the above-ground took up N 2.97 g·m~(-2)·a(-1), the N re-transtocation was about 1.54 g·m~(-2)·a~(-1) from above-ground to root. The N of above-ground biomass that turned to litter N is 1. 43 g·m~(-2)·a~(-1). Approximately 1.08 g·m~(-2)·a~(-1) N in litter changed to soil organic N, and 1.52 g·m(-2)·a(_1) of N from the root changed into soil organic N.Comparison between Canadian mixed prairie and Northeast China L. chinensis grasslands indicates that the utilization efficiency of soil N for grasses is lower in L. chinensis grasslands than that in Canadian mixed prairie.
学科主题	植物学
语种	中文
内容类型	期刊论文
源URL	[http://111.203.20.206/handle/2HMLN22E/17660]
专题	农业环境与可持续发展研究所
作者单位	中国农业科学院农业气象研究所, 北京, 100081
推荐引用方式 GB/T 7714	李玉中,王庆锁,钟秀丽,等. 羊草草地植被－土壤系统氮循环研究[J]. 植物生态学报,2003,27(2):177-182.
APA	李玉中,王庆锁,钟秀丽,&任娜.(2003).羊草草地植被－土壤系统氮循环研究.植物生态学报,27(2),177-182.
MLA	李玉中,et al."羊草草地植被－土壤系统氮循环研究".植物生态学报 27.2(2003):177-182.