The aim of the conducted study was to assess the effect of two types of stubble catch crops (a mixture of legumes and white mustard) as well as varied nitrogen fertilization on weed infestation of a spring wheat stand depending on the adopted tillage system. Weed infestation assessed at the tillering phase of spring wheat showed the lowest number of weeds in direct sowing after the mixed legume catch crop. The next assessment of weed infestation performed at the flowering phase of spring wheat showed that the lowest number of weeds was found in direct sowing immediately after the catch crop of a mixture of legumes and white mustard for the complete nitrogen fertilization rate. The lowest weed dry weight was recorded in conventional tillage after a mixture of legumes for the complete nitrogen fertilization rate and after white mustard for a reduced nitrogen fertilization rate.

SUMMARYThe strategic goal to the solving problem of dietary and fodder protein and restoring fertility of Ukrainian soils is optimal expansion of sowing areas traditional and non-traditional legumes. Creation of materials which are easily assimilated by living creatures and not harmful to the environment is one of the important issues of modern nanotechnologies. The aim of our study was the comparative evaluation of pre-sowing treatment with nanomolybdenum and microbiological preparation for impact on the efficiency of symbiotic nitrogen fixation in pea and chickpea plants. Field studies were conducted in the separated subdivision of the National University of Life and Environmental Sciences of Ukraine «Agronomic Experiment Station» on the typical black soils in the northern part of Forest Steppe of Ukraine. It was study of the influence of biological preparations on the nitrogen fixation capacity of pea (var. Tsarevych, Deviz) and chickpea plants (var. Rozanna, Triumf). The nitrogenase activity of the nodules in the root system of legumes was determined by acetylene-ethylene method. The efficiency of legume-rhizobia symbiosis depends on the number and virulence of symbiotic bacteria, which makes fixation of atmospheric nitrogen. Pre-sowing seeds treatment by strain of microorganisms enhances the quantitative and qualitative increase in the efficiency of the legume-rhizobia symbiosis. Using colloidal solution of molybdenum without seed inoculation also influences the number and diversity of rhizobia in the soil. Number, weight and symbiotic activity of nodules of pea and chickpea plants varied depending on the weather conditions. In the flowering stage the effects from pre-sowing treatment by bacterial inoculants and molybdenum solutions was most notable -the number of nodules was greater at 50-150 % compared with control, using inoculation this figure was higher at 8-9 %.