Einfluss des ökologischen Landbaus auf unterschiedliche Humuspools im Boden und Schlussfolgerungen zur Humusbilanzierung

Due to the results of organic matter balancing which showed a very high potential of soil organic matter accumulation in organic farming, a research project was started in spring 2005 with the objective to ascertain this hypothesis. Soil sampling was carried out on different organic and adjacent conventional farms in distinct regions of Ger-many. A comparison of the samples regarding Corg showed only minor differences between organic and conventional farms whereas the more sensitive indicators like Cmic and enzyme activities were more affected. However the main influencing factor of all these indicators in this investigation is soil texture. The cultivation system (inten-sive, extensive, stocking, crop rotation, tillage) is more important than the differentia-tion organic or conventional farming

Wirkungen differenzierter Bodenbearbeitungssysteme im Dauerversuch Scheyern

After a 12-year differing tillage in a 7-phase crop rotation with lay, potatoes, wheat, sunflowers, lay, wheat and rye it was found, that mouldboard-ploughing (P) resulted in less weed. Crop yields were as high as in the treatment with ploughing after lay and chiselling after potatoes and sunflowers (B). Lowest yields were obtained without ploughing but using the chisel (G). Weeds, esp. grasses, resulted in a huge competition for crops esp. after lay. Profit margins were highest in B due to lower expenditures for tillage and lowest in G. Soil organic carbon amounts differed by 1,5 t/ha and earthworm biomass by 0,25 t/ha between P and G after 12 years. It can be summed up for this experiment that G was not sustainable due to weeds and declining yields, and that B resulted in best economic profit, increasing SOM content and seems to be a sustainable compromise