The relation between earthworm populations and site properties was studied in a gleyic and in a calcaric cambisol. In the wet gleyic cambisol the earthworm biomass was 54 % higher than in the drier calcaric cambisol. By increasing the aeration of the soil and a more intense mixing of organic and mineral soil constituents, earthworms generally enhance the activity of soil micro-organisms. On the other hand both groups of organisms are feeding on dead soil organic matter, thereby competing with each other. A strong reproductive and intensive nutrient mineralizing activity of earthworm populations may therefore – depending on the site conditions – reduce the development of microbial biomass in soil. In order to understand nutrient cycling in soil, population dynamics and metabolic activity of earthworms have to be considered.
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.