Crop and soil factors of importance for the distribution of plant species on arable fields in Denmark

Analyses of spatial variation in multi-species weed communities together with environmental factors may be useful as a tool for developing sustainable long-term weed control and to better understand the ecology of weed species. We present an analysis of species recorded in 491 Danish fields surveyed in 2001–2004 distributed in 11 common agricultural crops. By using cluster analysis and canonical correspondence analysis (CCA) we identify crops that resemble each other with respect to their associated flora. By CCA, correlation and regression analyses we illustrate how the incidences of 40 common species relate to each other and can be related to important soil factors measured in the uppermost 20 cm. Clay content, pH, phosphorous, exchangeable potassium and magnesium, total nitrogen and carbon content in the soil were estimated.