title: Effects of nitrogen and water addition on trace element stoichiometry in five grassland species.
abstract: A 9-year manipulative experiment with nitrogen (N) and water addition, simulating increasing N deposition and changing precipitation regime, was conducted to investigate the bioavailability of trace elements, iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in soil, and their uptake by plants under the two environmental change factors in a semi-arid grassland of Inner Mongolia. We measured concentrations of trace elements in soil and in foliage of five common herbaceous species including 3 forbs and 2 grasses. In addition, bioaccumulation factors (BAF, the ratio of the chemical concentration in the organism and the chemical concentration in the growth substrate) and foliar Fe:Mn ratio in each plant was calculated. Our results showed that soil available Fe, Mn and Cu concentrations increased under N addition and were negatively correlated with both soil pH and cation exchange capacity. Water addition partly counteracted the positive effects of N addition on available trace element concentrations in the soil. Foliar Mn, Cu and Zn concentrations increased but Fe concentration decreased with N addition, resulting in foliar elemental imbalances among Fe and other selected trace elements. Water addition alleviated the effect of N addition. Forbs are more likely to suffer from Mn toxicity and Fe deficiency than grass species, indicating more sensitivity to changing elemental bioavailability in soil. Our results suggested that soil acidification due to N deposition may accelerate trace element cycling and lead to elemental imbalance in soil-plant systems of semi-arid grasslands and these impacts of N deposition on semi-arid grasslands were affected by water addition. These findings indicate an important role for soil trace elements in maintaining ecosystem functions associated with atmospheric N deposition and changing precipitation regimes in the future.
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Jiangping
authors.initials: J
authors.lastname: Cai
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Weiner
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
authors.forename: Ruzhen
authors.initials: R
authors.lastname: Wang
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Luo
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
authors.forename: Yongyong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
authors.forename: Heyong
authors.initials: H
authors.lastname: Liu
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
authors.forename: Zhuwen
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: College of Environmental Science, Shenyang University, Shenyang, 110044, China.
authors.forename: Yuge
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China. jiangyong@iae.ac.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D002681:China; D003300:Copper / Q000378:metabolism; D065948:Grassland; D007501:Iron / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D006109:Poaceae / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D014131:Trace Elements / Q000378:metabolism*; D014867:Water / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
chemical_list: D012987:Soil; D014131:Trace Elements; D014867:Water; D008345:Manganese; D003300:Copper; D007501:Iron; D015032:Zinc; D009584:Nitrogen
keywords: Elemental uptake; Fe deficiency; Mn toxicity; Nitrogen deposition; Nutrient bioavailability; Precipitation regimes