Ute Petersen, Tatiana From, Dr. Nicole Wrage, Prof. Dr. Johannes Isselstein


Productivity and yield formation of grass swards of different plant species diversity in relation to management system

Our project within the GrassMan experiment deals with the above-ground productivity of the grass sward in terms of quality and quantity. We will analyze the effects of different management intensity as well as different species diversity within the swards on their productivity. The main focus will be put on the amount of dry biomass produced under each management type at the different sward diversity levels and its quality in terms of nitrogen, phosphorus and potassium contents. Further on, the vertical structure, light utilisation and leaf area index (LAI) of the different swards will be analyzed as a whole and with respect to different functional groups - grasses, herbs and legumes. In addition, the state of the sward will be characterised by the constant monitoring of tiller numbers and vegetative buds. The nitrogen allocation within the different swards is also of particular interest to us.

The second phase of the project is an on-going study of the above-ground productivity of the grass sward in terms of quality and quantity. Analysis of effects of different management intensities and species diversity within the swards on their productivity will be continued. Dry biomass production and its quality in terms of nitrogen, phosphorous, and potassium will stay the main focus of research in order to receive a long-term data series. Another focal point of research will be calculation of functional diversity indices for the GrassMan experimental ecosystem using the multi-functional approach of plant functional traits as suggested by Petchey and Gaston (2002). Further on, we will try to proceed with dry biomass estimation on a smaller scale to test the possible variability in the plots and its influence on the data-set.