THE EFFECT OF GREEN MANURE ON THE DISTRIBUTION OF COLLEMBOLA IN A PERMANENT ROW CROP

Biomass, abundance, species composition of collembola, soil water cont ent, and bulk density were investigated in four hop fields in Southern Bavaria. For each soil type, one field was supplied only with mineral fertilizers, and the second was additionally cultivated with undersee d (oil-seed rape) to provide a green manure. Soils within and between rows were sampled separately over 2 years. The highest biomass of coll embola was found in the sandy soil with underseed, whereas the individ ual numbers were highest in the loamy soil with underseed. In many cas es total individual numbers and abundances of single species differed between soil types, green manure/mineral fertilization, and the sampli ng points (plant rows/rows between the plants). There were significant but low negative correlations between individual numbers of single sp ecies and water content (except for Isotomurus palustris) or bulk dens ity. All results of this study were based on very common, widespread s pecies. It is concluded that species abundances of collembola, even if they are euryoecious, are good indicators of soil type and different environmental conditions within the same soil type. The investigation of abundance and biomass showed that none of these parameters on its o wn was appropriate to compare populations either between or within the habitats investigated. Since both individual numbers and the standing crop of a population are important for nutrient turnover, in studies dealing with element fluxes their comparative analysis is indispensabl e.