Sorghum is a marginal plant in the sowing structure, therefore there is no chemical protection against its weed infestation. The usefulness of herbicides and their mixtures in weed control in maize, a plant related in origin to sorghum, provides the possibility of their use, if their selectivity is demonstrated in this crop. For this reason, before setting up field experiments, three series of biological tests were performed with several herbicides in a greenhouse. On the basis of evaluation of phytotoxic effects of herbicides and their mixtures, four most selective ones were selected for further field trials and applied in two different soil stands: phaeozem and lessive soil. Field experiments were conducted in the years 2009-2011 with randomized block design near Wroclaw. The obtained results indicated that on both soil stands, tritosulfuron + dicamba with an adjuvant was the most effective in selective control of weeds with high proportions of Chenopodium album, Solanum nigrum and Viola arvensis.

Using in substrates superabsorbents, also called hydrogels, contributes to considerable savings of water. Lawn turf quality depends largely on frequency of watering, having the effect on financial savings while incurring expenses connected with management of turf lawns. The aim of this study was to assess wintering of different turf lawns depending on the depth of placing hydrogel in the substrate and the type of soil cover. The study was conducted based on two field experiments established in three replications, carried out in the split-plot design. The experimental unit was a plot of an area of 1 m². The treatment of first experiment was a monoculture lawn, where four species of lawn grasses were studied in pure sowing. In the second experiment four designed mixtures of the same grass species were used. In each mixture one grass species was sown as dominant (40%), and the other three species accounted for 20% each: M1 – 40% of perennial ryegrass; M2 – 40% of red fescue; M3 –40% of Kentucky bluegrass; M4 – 40% of fine bent grass. The following experimental factors were used in each experiment: type of substrate: a) without hydrogel „0” –control; b) with addition of hydrogel placed at a depth of: 5, 10 and 15 cm; soil cover: a) arable soil (P), b) garden peat (T). Monoculture turf of perennial ryegrass and red fescue wintered best. Mixtures with domination of both grass species also were characterized by better wintering. Degree of turf wintering was determined by the type of soil cover; the best wintering, irrespective of the type of lawn, was provided by placing hydrogel in the substrate at a depth of 5 and 10 cm.

The response of two cultivars of blue lupine – Zeus and Kalif – to the bacterial inoculant Nitragina was estimated in this study. Field experiment was carried out in 2009-2011. It was located at the Experimental Station of the Faculty of Biology and Agriculture in Krasne, owned by the University of Rzeszów. In comparison to the control, application of Nitragina results in prolongation of the budding and flowering stages, as well as a delay in reaching the full maturity of plants. After inoculation of seeds with nodule bacteria the number of pods per plant and TSW increased significantly, whereas the number of seeds per pod did not change. The use of Nitragina resulted in a significant growth in seed yield by 0.3 t·ha^-1, i.e. 13%,as compared with the control. In 2009 cultivar Zeus gave significantly higher yield than cultivar Kalif. In following years of the study the studied cultivars yielded on a statistically similar level. Cultivar Kalif, in comparison with Zeus, was characterized by a longer growing period and significantly smaller number of pods per plant. Total protein content in seed dry matter increased significantly under the influence of bacterial inoculant in relation to seeds obtained from not inoculated plants.

In years 2009-2011, four strict field experiments were carried out whose aim was to evaluate herbicides registered for maize applied at lowered doses, against variable weather conditions. Herbicides were applied in the following system: preemergence treatment with s-metolachlor + terbuthylazine + mesotrione and foliage treatment at the 4-6-leaf stage of maize with nicosulfuron + rimsulfuron, nicosulfuron, rimsulfuron, and foramsulfuron + iodosulfuron. Adjuvant Atpolan Bio 80 SL was added to herbicides used in the foliage treatment. Regardless of the weather conditions in the particular growth seasons, the best maize weeding effects were obtained after the preemergence application of the mixture s-metolachlor + terbuthylazine + mesotrione, and subsequently the foliage application of nicosulfuron with adjuvant Atpolan Bio 80 SL. In the conditions of delayed and uneven weed emergence (especially the thermophilic weed species), the system of two treatments with lowered herbicide doses protected most effectively the maize plantation against secondary weed infestation.

Field experiment with winter oilseed rape cultivation was carried out in 2007-2009. The subject of this study was analysis of weed infestation of winter oilseed rape canopy and seed yield depending on the rate of soil NPK fertilization and foliar application (autumn spraying with solution): 100% and 75% NPK and urea + nickel chelate + MgSO4H2O; 100% and 75% NPK, as well as urea + Plonvit R + MgSO4H2O). The control was plots without foliar fertilization (only 100% NPK). Foliar sprayings were carried out as a single rate in autumn between 10^th and 20^th of October. The second experimental factor was seed sowing rate (2.5 kg·ha^-1 – row spacing 30 cm; 4 kg·ha^-1 – row spacing 18 cm). It was found that foliar fertilization of winter oilseed rape in the autumn period contributes to a reduction in quantitative indexes of weed infestation and an increase in seed yield. Application of foliar fertilizers allows for reduction in rates of the basic mineral fertilizers NPK by.¼ From the point of view of production it is justified to reduce the seed sowing rate (2.5 kg·ha^-1), since the weed infestation and yield of winter oilseed rape did not differ significantly from the parameters observed under conditions of larger sowing density.

The aim of this investigation was assessment of variability of winter wheat cultivars yield under variable stubble height conditions and different tillage systems. The study was carried out during 2009-2011 and it was localized on good rye complex. The first factor was stubble height: a) low stubble (10 cm), b) high stubble (40 cm). Within the second factor three systems of tillage were evaluated: a) conventional tillage, b) reduced tillage, c) notillage. The third experimental factor was winter wheat cultivar: a) Mewa, b) Rapsodia, c) Legenda. Plowless tillage contribute to decrease wheat yield in comparison with conventional tillage applied after cereals. In treatments with high and low stubble the yield of winter wheat cultivars Legenda and Rapsodia was the highest while Mewa gave the lowest yield. Yield stability under high stubble conditions in plough and simplified tillage was much lower than under low stubble conditions.