Prof. Han Dolman
Vrije Universiteit Amsterdam
Faculty of Earth and Life Sciences, Department of Hydrology and Geo-environmental Sciences
Professor Dolman works in the field of carbon cycling from global to local systems. His lecture will enlighten the global context of the research work on livestock-environment interaction as conducted at the Animal Production Systems Group (see abstract below).
Abstract
Zodiac, Marijkeweg, Wageningen, Gelderland, The Netherlands, Europe, Earth, Solar system, Universe. Many children have playfully listed this hierarchy of systems. The first mentioned is part of the second and so on. When describing the interaction between animal production and environment we consider a similar kind of system hierarchy: the issue of nitrogen can be regarded at the level of animal, plot, farm, production sector, region and planet. It is noteworthy that indicators differ between system levels: at animal level we assess efficiency of Nitrogen (N) utilisation, at farm level we assess N-surplus by the Mineral Accounting System MINAS and at the regional level we measure the nitrate concentration in sub-soil water or the forest health as an indicator of ammonia emission. Forest health and sub-soil water quality are the eventual objectives at the highest system level for which measures are taken at the lower system levels. Understanding of the processes and interactions at the higher system level are essential to identify relevant measures at lower system levels.
The environmental interaction of nitrogen and phosphate is relatively regional; the effects of livestock production and agriculture on the carbon cycle act at the global level. Livestock production, for example, releases fixed carbon by fuel use, by methane excretion from rumen fermentation, and by forest clearing to increase the area for feed crops. However, livestock in mixed farming systems in the tropics enhance carbon fixation in crop biomass through their manure. Understanding the system earth and the changes and behaviour of this system will eventually be essential to define the relevant measures at lower system levels to be taken to minimise unwanted environmental interactions of human activities, including livestock production.