As part of the project ’Optimisation of Grassland-Based Milk Production Systems based on Fresh-Grass Harvesting (Hohenrain II)’, we used the SALCA life-cycle assessment method to compare the environmental impacts of three systems, viz. full-grazing with seasonal calving and two variants of fresh-grass harvesting with differing use of concentrates (< 500 kg/cow/ year and 800–1200 kg/cow/year). Systems using higher amounts of concentrates had higher, and hence less favourable, scores in the ’potassium resource demand’ and ’ecotoxicity’ categories, as well as in the ’phosphorus resource demand’ and ’deforestation’ categories in some instances, than systems using lower amounts of concentrates. By contrast, for ’global warming potential’, ’ozone formation’ and ’landscape aesthetics’, the system using higher amounts of concentrates in some cases had more favourable scores than the full-grazing system. In several additional impact categories there were no obvious differences between the systems, owing to the high variability between the farms and years investigated. The main factors influencing the environmental impact of milk were feed conversion (kg feed/kg energy-corrected milk [ECM]), composition of the feed ration, concentrate intake, cattle restocking, and fertiliser application.
Symbiotic nitrogen fixation by bacteria in the soil coexisting with legumes leads to reduced fertiliser requirement. It is not easy to measure this variable on farms, however. Now researchers from Agroscope have developed a method for estimating nitrogen input via symbiotic fixation at farm level.
With increasing global and regional temperatures, even in Switzerland the growing season has lengthened considerably. Using data from the Federal Office of Meteorology and Climatology, Agroscope has traced the development of the growing season since the start of the previous century.
The phosphate mineral reserves required for fertiliser production could be exhausted on a global scale in just a few decades. This study presents a method for recycling a Swiss industrial by-product into a phosphate fertiliser.