TP4-1: Tree/grassland interactions

Grassland tissue and litter production as affected by tree x grass sward interaction and grassland management

Summary

In grassland systems the turnover of matter and nutrients is controlled by a range of processes, which directly affect nutrient use efficiency and nutrient losses. In silvo-pastoral systems the nutrient turnover in grassland is further modified by the trees. Immediate sources for C and N in grasslands are excreta of grazing animals, microbial biomass and plant litter, i.e. the herbage that remains unused and contributes to the soil organic matter via senescence and decomposition. Litter makes up 50% or more of the total herbage production, even in intensively managed grasslands. The amount of litter is controlled by a range of factors such as the frequency and type of defoliation and the availability of nutrients, water and light. Litter formation in a grassland sward is also closely related to the phyllochron, which is the leaf appearance on a shoot, and the leaf life span. Our objective is to study the combined effects of competition between trees and grass sward and of grassland management on the herbage growth and tissue turnover in the grass part. We want to find out about processes that determine the sward development and productivity of grassland in agroforestry systems. Besides, leaf development and senescence form a direct link of N and C cycling between plant and soil. At two sites we will apply the rising plate meter technique to study matter production and turnover in established plots and along transects. At one site we will additionally focus on leaf development and senescence and how these processes depend on environmental factors, leaf life span and sward composition. To do so we consider three scales of observation from the single plant to the species and sward scale. Our research contributes to the elucidation of fundamental principles of yield and quality development of grassland in agroforestry in temperate climates. This knowledge is necessary to properly control and manage these systems.

 

 

Contact

Prof. Dr. Johannes Isselstein

University of Göttingen, Department of Crop Sciences, Grassland Science
von-Siebold-Str. 8, 37075 Göttingen, Germany

Phone: +49 (0)551 3922253
Fax: +49 (0)551 399355
Email: jissels(at)gwdg.de

Dr. Manfred Kayser

University of Göttingen, Department of Crop Sciences, Grassland Science
von-Siebold-Str. 8, 37075 Göttingen, Germany

Phone: ++49 (0) 4441 15508
Fax: ++49 (0) 4441 15469

Dr. Bettina Tonn

University of Göttingen, Department of Crop Sciences, Grassland Science
von-Siebold-Str. 8, 37075 Göttingen, Germany

Phone: ++49 (0)551 39 4358
Email: btonn(at)uni-goettingen.de

A. Schmiedgen (PhD student)

University of Göttingen, Department of Crop Sciences, Grassland Science
von-Siebold-Str. 8, 37075 Göttingen, Germany