The effect of biodiversity on nutrient cycling in an experimental grassland

实验草地群落的物种和/或功能多样性可能会影响土壤养分循环。我们建议的目标是：（1）量化养分保留（2）确定土壤溶液中有机氮、磷、硫对养分循环的贡献，（3）利用土壤无机氮同位素组成评价不同草地群落土壤氮素过程。我们将收集土壤固相样品，降水上方和下方的草冠，并在10，20，30和60厘米的土壤深度在耶拿生物多样性实验的四个区块之一，并在30上午深度在其他两个区块（66块）的多孔吸盘板土壤溶液。干沉降将采用氯化物示踪法进行估算。将与水文分项目密切合作，利用现有模型评估养分流失情况。我们期待答案的问题，无论是增加物种多样性本身或增加功能多样性的结果，增加养分的使用，以及是否更多样化的草地系统是更稳定的比少多样性的系统所示的营养投入和产出之间的平衡。

Species and/or functional diversity of experimental grassland communities may influence the soil nutrient cycle. The objectives of our proposal are (1) to quantify nutrient retention (N, P, K, Ca, Mg, S, Cu, Mn, Zn) by setting up an ecosystem budget including all inputs and outputs, (2) to determine the contribution of organic N, P, and S in soil solution to nutrient cycling, and (3) to assess soil N processes with the help of the N isotope composition in inorganic N species in differently diverse experimental grassland communities. We will collect soil solid phase samples, precipitation above and below the grass canopy, and soil solution with porous suction plates at 10, 20, 30, and 60 cm soil depth in one of the four blocks of the Jena biodiversity experiment and at 30 am depth in two other blocks (66 plots). Dry deposition will be estimated with a chloride tracer method. Nutrient leaching will be assessed with available models in close cooperation with the hydrological subproject. We expect answers to the questions whether increasing species diversity per se or increasing functional diversity result in increasing nutrient use and whether more diverse grassland systems are more stable than less diverse systems as indicated by the balance between nutrient inputs and outputs.