The influence of grassing and harvest management on microbial parameters after arable land setting-aside

During the years 1998-2000 soil chemical (Corg, Nt, pH), textural (sand, silt clay) and microbiological (microbial biomass carbon - CMB, microbial extracellular carbon - CEX, respiration, ammonification, nitrification) characteristics were tested on grassed chernozem [mollisol] after arable land setting-aside. Different harvest management was also tested: black and green fallow, one or two mulching per year, three cuts with plant biomass removal. For the evaluation of the influence of management and plants we have used three main criteria: (1) µg CMB/g dry soil, (2) ratio CMB/Corg (%), (3) µg CEX/mg CMB or eight criteria respectively: (4) ratio of measured and model values of CMB, (5) ratio of measured and model values of CEX/CMB, (6) potential respiration with glucose, (7) potential ammonification with peptone and (8) potential nitrification with (NH4)2SO4. According to these criteria, the best harvest management after arable land setting-aside from 5 different systems, which were tested, could be based on one or two mulching per year. It could be stressed that the two mulching was evaluated as the best in sum of dry mass yield (27.5 for mixtures, 20.1 for legumes and 14.2 for grasses - in t/ha/3 years). The use of legumes (Trifolium repens L. - Medicago lupulina L. - Lotus corniculatus L. - Medicago media Pers.) or grasses [Bromus catharticus Vahl - Arrhenatherum elatius (L.) Presl - Festuca pratensis Huds - Dactylis aschersoniana Graebn.] as cover plants was more successful than the use of their mixtures.