Most quality characteristics of potato tubers are affected by an interplay of plant genetic traits and environmental factors, including weed control. As a result, detailed studies on plant responses to changing agrotechnological factors seem to be justified. It was attempted in the present work to determine the effect of weed control methods on total and true protein content in two kinds of table potato tubers. The field experiment was designed as a split-plot arrangement of the following two factors: potato cultivars: Irga and Balbina, and four weed control methods: 1 – mechanical weed control – control treatment, 2 – mechanical weed control + the herbicide Plateen 41.5 WG at the rate of 2.0 kg·ha^-1, 3 – mechanical weed control + the herbicide Racer 250 EC at the rate of 3.0 dm³·ha^-1, 4 – mechanical weed control + the herbicide Sencor 70 WG at the rate 1.0 kg·ha^-1. The weed control methods examined in the study increased the total and true protein contents by an average of 0.04-0.14 and 0.02-0.06%, respectively. Compared with the control treatment, a significantly higher total protein content was found in treatment 3, where a combination of mechanical and chemical control had been applied (one hilling + spraying with Racer 250 EC at the rate of 3.0 dm³·ha^-1 10 days after planting), and in treatment 4, where mechanical and chemical control had been applied, too (two hillings combined with harrowing before emergence of potato plants + Sencor 70 WG at the rate of 1.0 kg·ha^-1 applied just before emergence. The highest true protein content was determined when weeds were controlled mechanically and chemically using Sencor 70 WG. The study results demonstrated that Irga had a higher concentration of total protein and true protein, on average 9.89 and 6.70%, respectively, compared with Balbina (9.11 and 6.44%, respectively). The weather conditions in the study years significantly affected the total and true protein contents which were the highest in 2007 when the temperature was the most suitable for potato development.

Introducing cultivars of yellow lupine that tolerate delays in the sowing dates (thermoneutral) or ones that ripe faster (self-completing) into agricultural practice makes it possible to broaden the cultivation of this agriculturally valuable species. The aim of the study was therefore the determination of the effect of the sowing date on the size and quality of the seed yield of yellow lupine in the mountain-foot region. It was hypothesized that cultivars Mister (conventional) and Taper (self-completing) would react differently to the applied study factor. Strict experiment was carried out in years 2011-2013 at the Cultivar Assessment Experimental Station in Dukla on 5^th class soil of mountain oat-potato complex. Sowing date and diversified weather conditions in the study years had a significant effect on plant growth and development. The highest plant density before harvest was obtained on the second sowing date (second ten days of April), and the lowest on the first sowing date (first ten days of April), which was statistically significant. Sowing dates significantly modified such yield characteristics as the number of grains per pod and mass of 1000 grains, whereas the number of pods per plant was constant. On average in the study years, significantly higher yield was obtained after sowing the seeds in the first twenty days of April than in the last ten days of April. This relation was not, however, repeated in the study years. With the delay in the sowing date, total protein content in the seeds decreased. Cultivar Mister in comparison with cultivar Taper was characterized by a significantly higher pod number per plant, mass of 1000 grains, and seed yield. It was also proved that cultivar Mister contains significantly more crude fat in the seeds than cultivar Taper. Established percentage of total protein, ash, and fibre was not diversified between the studied cultivars.

The effects of legume-cereal mixtures are usually expressed in the yield of seeds and total protein, sometimes in the yield of straw and post-harvest residues. Species composition and proportion of components in the mixture are a factor that strongly varies it. The aim of the research was determining productivity (the yield of seeds and straw as well as of the biomass of post-harvest residues) of a mixture of field pea with spring barley on the plot after potato, spring barley and after itself. The studies were carried out based on a statistical field experiment set up on rusty-brown soil, developed from silty loamy sand, deposited on slightly loamy sand and sand. The legume-cereal mixture was cultivated in six 4-plot crop rotations with its 25and 50% proportion. In the growing season, no chemical protection was applied against diseases and weeds, however, zoocides were used against pests. It was indicated that yield of the seed mixture was similar compared to plots with crop rotation. Selection of the forecrop also did not have an effect on the straw yield, while it significantly varied the biomass of post-harvest mixture of barley with pea. The smallest quantity of residues was found after potato, while the largest in the crop rotation with field pea. In the structure of residual biomass, roots constituted lower proportion than the aboveground parts. The total production of the biomass of legume-cereal mixture, expressed in the total aboveground and underground biomass of mixture canopy was significantly higher in the crop rotation with field pea than after potato, where there occurred a significant reduction in biomass of the aboveground vegetative part of the plant.

The studies were carried out in the years 2009-2011 on medium heavy mixed rendzina soil. The aim of the study was comparison of the effect of tillage system and different types of catch crops on the weed infestation level in spring wheat canopy sown in monoculture. The experiment included plough tillage and conservation tillage with autumn and spring disking of catch crops. Four methods of plot regeneration were used in a form of various catch crops. With reference to the control without catch crops, effects of undersown red clover and Dutch ryegrass were compared, as well as of stubble crops of lacy phacelia and white mustard on the weed infestation of spring wheat canopy. Based on the conducted research it was indicated that plough tillage compared with conservation tillage decreased a number of dicotyledonous and monocotyledonous weeds, the total number of weeds and their air dry mass in the spring wheat canopy. Under conservation tillage, compared with plough tillage, there was a higher occurrence of Avena fatua and Cirsium arvense. Greater species diversity in weeds was observed on plots with conservation tillage. A lower number of monocotyledonous weeds was observed on the plot after stubble crop of white mustard, compared with the control plots where no catch crops were sown. Incorporation of both stubble crops and undersown red clover decreased dry weight of weeds in a spring wheat canopy, both compared with the control and with the plot after undersown grass. On plots after undersown red clover and Dutch ryegrass, a higher number of weed species was observed in the spring wheat canopy, compared with the control without catch crops. Conservation tillage promoted obtaining a higher biomass of catch crops than plough tillage. Undersown red clover produced a significantly lower biomass than stubble crops or undersown Dutch ryegrass.

Oil in Echium plantagineum (purple viper’s bugloss) seeds is rich in polyunsaturated fatty acids including the rarely occurring γ-linolenic acid and stearidonic acid. Therefore, the oil is used in pharmacy and food industry. Boron, magnesium and sulphur play an important role in physiological processes of plants. Polish soils, however, in majority are deficient in these elements. The aim of the experiment was to compare the effects of two methods of fertilization (into soil and foliar one) with boron, magnesium and sulphur on growth and seed yields of purple viper’s bugloss. The study was carried out on silt loam soil characterized by the mean content of magnesium and sulphur and a low content of boron. Afore-named elements, irrespectively of the application method, brought about a significant increase in the height of plants, their vegetative mass, and induced better development of seeds. As a result, yields of seeds on plots with boron, magnesium and sulphur fertilization were significantly higher in comparison with the control (it should be stressed that impact of boron was the greatest). Fertilization had a positive effect on the fat content in seeds too, resulting in an increase by 0.2%-1.6% (boron was the most effective in this respect too). Results of the present study showed that application of fertilization with boron, magnesium and sulphur had a significant effect on the yield and oil content in purple viper’s bugloss seeds.

Right selection of hybrid for cultivation is an especially important issue because maize belongs to a group of plants undergoing considerable breeding development. It is manifested not only in a higher number of new hybrids but also in changes in selection of various breeding types. The field experiments were carried out at the Department of Agronomy of the University of Life Sciences in Poznań, on the fields of the Agricultural-Experimental Station Swadzim in the years 2009-2011. The occurrence of frit fly (Oscinella frit L.) on various maize hybrids (ES Palazzo and ES Paroli – type stay-green) was evaluated, depending on the nitrogen content in the soil, and on the form of a nitrogen fertilizer. It was indicated that the course of weather conditions in the period from sowing until the 5-6 leaf stage (BBCH 15/16) significantly affected the extent of damage caused by frit fly. In the years with a cool spring, percentage of damaged plants was higher. Damage caused by frit fly larvae was directly proportional to the size of the applied dose of a nitrogen fertilizer. The type of a nitrogen fertilizer was not the factor determining the extent of damage caused by this agrophage. Cultivation of stay-green hybrids should be considered as an element of an integrated maize protection against frit fly.

This study estimated the amount of nitrogen taken up by spring triticale from different sources depending on varied nitrogen fertilization and the development phase when the previous crop – yellow lupine was harvested. Lupine was cultivated in three fertilization variants: without nitrogen fertilization and after the application of rates 30 kg·ha^-1 N and 150 kg·ha^-1 N. Lupine harvest was performed in full flowering and full maturity phases. At the first harvest time, the whole biomass was introduced into soil. At the second time, seeds were collected and the other parts of lupine were introduced into soil. Spring triticale as a successive crop was cultivated without additional fertilization with nitrogen and harvested in the full maturity phase. Ammonium sulfite enriched in nitrogen ¹⁵N isotope was used in the study as well as the method of isotopic dilution. The highest yield of grain and the whole biomass as well as the total amount of nitrogen taken up by triticale were obtained after the application under lupine of 150 kg·ha^-1 N. Yields and nitrogen uptake by triticale were higher when the previous crop was harvested in flowering than in full maturity. Nitrogen content in triticale grain and biomass was not dependent on the harvest phase and nitrogen fertilization of the previous crop. Proportion of nitrogen taken up by triticale from soil resources, from parts of lupine introduced into soil and from mineral fertilizer applied under lupine amounted to 71,0; 17,2 i 11,8%, respectively, of the total amount of this macroelement accumulated in the biomass. Triticale took up on average 20.9% of biologically reduced nitrogen introduced into soil with the lupine biomass.

The purpose of this study was to determine the effect of the soil conditioner UGmax on nitrogen, phosphorus and magnesium contents in potato tubers. A field experiment was carried out at the Zawady Experimental Farm in 2008-2010. The trial was set up as a split-plot design with three replications; the soil was classified as the very good rye complex of soil quality. The following factors were examined: factor I: table potato cultivars (Satina and Tajfun), and factor II: timing and method of UGmax application: 1 – control – no UGmax, 2 – 1.0 dm³·ha^-1 – applied once before planting of potato tubers, 3 – 1.0 dm³·ha^-1 – split application: ½pre-plant and ½ foliar application, 2.0 dm³·ha^-1 – split application: ½ pre-plant and ½ foliar application, 4 – 1.0 dm³·ha^-1 – split foliar applications at two dates. UGmax significantly increased nitrogen content in potato tubers compared with the control. Split application of UGmax at the rate of 2.0 dm³·ha^-1 (pre-plant spraying followed by two foliar applications) was the best method of application. Moreover, the weather conditions in the study years and potato cultivars had a significant effect on nitrogen content in tubers. Satina accumulated more nitrogen than Tajfun. By contrast, neither UGmax application, cultivars nor weather conditions influenced phosphorus or magnesium contents in potato tubers.