Institut für Epidemiologie und Pathogendiagnostik
Due to their ability to fix nitrogen, legumes are a prerequisite for soil fertility in organic crop rotations. However, legumes, which can account for up to 50% of all crops in organic crop rotations, are susceptible to a range of aggressive pathogens. These pathogens include plant-parasitic nematodes, in particular endoparasitic species of the genera Meloidogyne and Pratylenchus, which multiply rapidly on legume roots and can thus lead to yield losses in subsequent crops. Here we ask to what extent plant-parasitic nematodes and other trophic nematode groups are influenced by three different organic crop rotation strategies with different legume cultivation intensity. In particular, we investigate the impact of the diversity of crop rotations, including different fertilization strategies, on nematode communities seeking for the most promising cultivation strategy that yields in the best trophic connectivity (high quantity + high diversity) of the nematode community. Additional quations that should be dealed with:1. Does crop rotation diversity affect soil nematode diversity? 2. Are the bacterivorous and fungivorous nematodes promoted by different fertilization treatments and thus also the natural nitrogen mineralization potential of the soil? 3. Which plant-parasitic nematodes play a role and under which types of farms do they particularly occur? 4. Which bioindicators derived from nematodes (see du Preez et. al. 2022) are suitable for differentiating farm types? Research object: At the beginning of each vegetation period (March/April), soil samples are taken from the long-term field experiment of the experimental farm of the Univerity of Kassel to extract and identify the entire nematode fauna. The first sampling took place 5 years after the start of the long-term experiment (2017). At the beginning (2022) 2 farm types with different focuses (market fruit vs. animal nutrition) and 2 fertilization treatments (control without differentiated fertilization vs. biogas manure (market crop farm) / manure compost and slurry from animal production (1.4 LU/ha)) were compared. In the following year, 2023, the "soil fertility-oriented" farm type was also tested with a focus on soil health and including the fertilization treatments "control" vs. "yard waste compost" (5 t/ha*year). For the following years (2024-2028), we planextend the nematode investigations to the fourth farm type "Human nutrition" with a focus on bio-vegan crop production.
Federal Ministry of Food and Agriculture
