THE ROLE OF PLANT DIVERSITY AND COMPOSITION FOR NITRATE LEACHING IN GRASSLANDS

作者：Michael Scherer‐Lorenzen, Cecilia Palmborg, Alexandra Prinz, Ernst‐Detlef Schulze · 发表于：Ecology · 年份：2003 · DOI：10.1890/0012-9658(2003)084[1539:tropda]2.0.co;2 · 被引用次数：314 · 研究领域：Soil and Water Nutrient Dynamics、Soil Carbon and Nitrogen Dynamics、Groundwater and Isotope Geochemistry

The relationship between plant diversity and nitrate leaching into groundwater was investigated in a mid-European semi-natural grassland ecosystem. An experimental approach was used to directly manipulate plant diversity in the field, while holding other environmental factors constant. Species loss was simulated by establishing grassland communities of 16, 8, 4, 2, 1, and 0 plant species, composed of 3, 2, or 1 functional groups (grasses, legumes, and non-legume herbs). Every diversity treatment was replicated with several different species mixtures. Nitrate leaching was determined by continuous extraction of soil solution below the rooting zone and modeling of seepage rates. The concentration of nitrate in the soil solution was highly variable within each level of diversity. In bare ground plots and several low-diversity mixtures containing legumes, nitrate concentrations were higher than the official European Union threshold value for drinking water of 50 mg/L, with maximum values of up to 350 mg/L measured in Trifolium pratense monocultures. Total annual loss of nitrate was unaffected by the number of plant species or functional groups, but it was highly dependent on the specific species composition of the communities, and plots with legumes lost significantly more nitrate than plots without them. Aboveground biomass had no influence on nitrate loss, whereas leaching was negatively correlated with increasing root biomass. The abundance of legumes within a community, litter...