I. MANOLOV, M. DIMITROVA and H. CHALAKOV
Agricultural University, BG-4000 Plovdiv, Bulgaria
MANOLOV, I., M. DIMITROVA and H. CHALAKOV, 2003. Effect of fertilizing system to weed infestation of winter cereal crops. Bulg. J. Agric. Sci., 9: 1–4
The effect of the fertilizing system on weed infestation in conditions of field crop rotation, as well as uptake of macronutrients from Cirsium arvense and Sinapis arvensis were studied. Four variants were included in field experiment – organic, organic-mineral, mineral fertilizing systems and unfertilized control. The weed infestation was the highest at the organic system (about 80 numbers of weed per m2), followed from the organic-mineral (about 65 numbers of weed per m2) and the mineral (about 60 numbers of weed per m2).
The weeds blocked considerable amounts of nutritional elements, which could be take up from the cultivated crops. One kilogram dry mass Cirsium arvense collected at the beginning of the vegetation contained about 36 g N, 5.3 g P2O5 and 33 g K2O. The Sinapis arvensis take up 30–50 g nitrogen, from 1.1 – 6.3 g phosphorus and 45–53 g potassium per kilogram dry mass, depending on the level of fertilization.