The effect of growing practice on the floristic composition and structure of weed synuzia in double cropped soybean

The paper deals with the floristic composition of weed synuzia in double cropped soybean, depending on the applied growing practices determined by different tillage systems, row spacing, and herbicide application. Weed synuzia on slightly calcareous chernozem soil type in Zemun Polje have consisted of relatively small number of species, predominantly of the summer aspect: Amaranthus retroflexus, Chenopodium hyhridum, Sorghum halepense, Convolvulus arvensis and only on the plots with wide interrow distance Datura stramonium. On the plots with No-tillage practice higher weediness have occurred comparing among examined variants under conventional tillage practice, both in presence of different weed species and its numbers, as well as weed biomass. Narrow-row soybean crop comparing to standard one with interrow distance of 76 cm was more competitive regarding weeds, fallowing decrease both in number and biomass. Combined application of herbicides that included pre-emergence treatment followed by post-emergence treatment considerably has affected total weediness reduction, showing high efficiency in control both of total weed abundance and biomass of weeds. An effective integrated weed management should include precise application of different cultural and chemical control tools and measures, especially under No-tillage practice which is very favorable regarding energy requirements and total inputs, helping us to create an innovative strategy for profitable production of soybean in double cropping system.