Greater vigour of plants that border with unsown areas, known as border effect, compensates for the use of tramlines in the lowland meadow but also gives an error to the results of field experiments. This phenomenon is well-known for certain cultivated plant species. However, there is a lack of publications which would make it possible to analyze and compare the border effect of several plant species in similar habitat conditions and evaluated in the same way. The aim of the study was to recognize and compare the border effect in the cultivation of spring cereals: wheat, triticale, barley, oat, pea, and yellow lupine, as well as to determine the effect of this phenomenon on yield overestimation in plot experiments. In years 2004-2010 at the University of Technology and Life Sciences Research Station at Mochełek (53^o13' N; 17^o51' E), a series of plot experiments was carried our, each according to the same methodology. Experimental factor was the situation of plant rows on the plot; four rows into the plots from the unsown path 50 cm wide were evaluated. It was found that the border effect resulted in greater values of nearly all the evaluated plant characteristics. Oat was the most susceptible to the effect. Border effect in cereals, in relation to most characteristics, was limited only to the row of plants directly adjacent to the path, while in the subsequent two rows the values of the particular characteristics were usually close to the evaluation of the fourth row. In the case of legumes, the effect was visible also in the subsequent two rows into the lowland meadow. Yields of plants harvested from the whole plot were greater by 18.3%-28.0% than in the mid area of the plot, depending on the plot area and plant species. It was also found that in order to avoid the border effect influencing yield size estimation, it is recommended to omit during harvest one border row of oat plants from both sides of the experimental plots and two rows of triticale and barley. In the case of wheat, lupine and pea, three rows of plants from each side of the plot should be excluded from harvest.

Cost reduction in plant production, as well as ecological aspects, force farmers to apply numerous modifications in tillage. Usually, they consist in shallowing ploughing and replacing it with cultivating measures not overturning the soil. The aim of the study was determination of the effect of conventional and reduced tillage systems as well as of two levels of mineral fertilization on the yield of spring wheat in the second cycle of crop rotation: potato spring wheat field pea (edible form) winter wheat. The research was carried out in the years 2003-2006 on lessive soil formed from loess included in the good wheat complex. Autumn tillage under spring wheat, cultivar Helia, included the following cultivation measures: A pre-winter ploughing (18-22 cm), B cultivatoring (10-15 cm), C heavy harrowing (8-10 cm). In spring, harrowing was conducted on all plots as well as cultivatoring, harrowing, seeding and harrowing. The second experimental factor was mineral fertilization on two levels: 117.3 kg NPK (50 kg N, 17.5 kg P, 49.8 kg K) and 175.9 kg NPK (75 kg N, 26.2 kg P, 74.7 kg K). The conducted research indicated that replacing pre-winter ploughing with cultivatoring (B) or heavy harrowing (C) resulted in a statistically insignificant yield decrease, by 4.3% and 7.1% respectively, as well as in a deterioration of its structural components. On lessive soil formed from loess, an increase in fertilization with nitrogen, potassium and phosphorus by 50% did not vary significantly the spring wheat yield or its components. Under conditions of a higher fertilization level, the yield increased by 4.1%. Spring wheat yield was significantly modified only by weather conditions in particular years of research. An increase in the yield and its structural components was indicated in the second cycle of crop rotation in all experiment variants, compared to the research from the years 1999-2002. Therefore, it may be concluded that reduced tillage, consisting in conducting shallow cultivating measures not overturning the soil, is well tolerated by spring wheat.

The aim of the study was to evaluate the effect of diversified nitrogen fertilization doses and application of various doses of herbicide Starane 250 EC on the total protein efficiency and carbohydrate:protein ratio of meadow sward. Two-factor field experiment was established on permanent meadow in the spring of 2007 in Żelków near Siedlce in a randomized subblock design in three repetitions. First experimental factor was diversified nitrogen fertilization in the amounts of: A1 0 kg N ha^-1, A2 90 kg N ha^-1, A3 180 kg N ha^-1, and A4 270 kg N ha^-1. The second experimental factor was herbicide Starane 250 EC applied at the doses of: B1 control group, B2 half a dose (150 g basic active substance ha^-1), B3 one dose (300 g basic active substance ha^-1), and B4 1.5 dose (450 g basic active substance ha^-1), according to the recommended instruction, namely 1.2 dm³ ha^-1. Plot size was 9 m². In every growth season, three cuts were harvested. In the study, total protein content (%) and soluble sugar content (%) in the meadow sward were determined. The obtained results were evaluated statistically with the analysis of variance for two-factor experiments. Mean differentiation was verified with the Tukey's test at the significance level of P ≤ 0.05. Significant effect of subsequent nitrogen fertilization doses on the protein efficiency of the meadow sward was demonstrated. With the increase in the nitrogen dose, the carbohydrate:protein ratio decreased and reached minimal, border nutritional values with the highest fertilization level. Diversified herbicide Starane 250 EC doses did not cause significant differences in protein efficiency or in the carbohydrate:protein ratio.

Economic, organizational and natural determinants of modern plant field production enforce far-reaching limitations of classical components of cultivation regime. In 2010-2012, a study was carried out at the Agricultural Production Farm in Kowróz (Kuyavian-Pomeranian voivodeship) in soil of the very well rye complex. This study aimed at determining the effect of plowing tillage, reduced tillage and minimal tillage on the grain yield and quality of winter wheat sown after winter oilseed rape, winter wheat and maize for grain. Plowing tillage involved performing: skimming, harrowing, pre-sow plowing and cultivation with a passive pre-sow unit after harvesting oilseed rape and wheat or single plowing and cultivation with a cultivation unit after maize for grain. Reduced tillage was performed using a stubble unit, grubber and pre-sow unit after oilseed rape and wheat, and a grubber and passive pre-sowing unit after maize. Minimal tillage consisted only of disking the stubble in each position. Yield components, grain yield and its quality were usually more dependent on the previous crop than on the tillage system. The highest yield of winter wheat 5.57 Mg·ha^-1 with favorable traits of grain quality was observed in the position after winter oilseed rape, and the lowest 4.92 Mg·ha^-1 after maize. Abandoning plowing tillage did not have a negative effect on spike density, grain yield and grain quality. Nevertheless, tillage simplification only to disking the stubble negatively affected the yield. However, in the position after winter wheat, and particularly after winter oilseed rape, this cultivation system did not have a negative effect on grain yield, grain bulk density and protein content. After harvesting maize for grain, each simplification of plowing tillage caused a reduction in winter wheat grain yield.

The effect of water extracts from common buckwheat (Fagopyrum esculentum Moench) tissues on seed germination and seedling growth of winter wheat and lettuce was examined. Two kinds of extracts were evaluated: from the aboveground parts and roots of common buckwheat (cv. Hruszowska). The effect of extracts was dependent on their kind, the time of action and the species of studied plants. Lettuce seeds were more sensitive to treating with extracts from buckwheat tissues than wheat seeds. Extract from the aboveground parts of buckwheat more clearly inhibited germination of wheat seeds than extract from roots. In lettuce the reverse phenomenon occurred: two times less seeds germinated in the presence of extract from aboveground parts of buckwheat than under the influence of extract from roots. Extracts from buckwheat tissues also inhibited the growth of roots of the studied species and the coleoptiles of wheat and hypocotyls of lettuce. Extract obtained from the aboveground parts of common buckwheat showed stronger inhibiting effect.

Municipal sewage sludge has a lot of organic matter and is a rich source of nutrients, thus generating interest as a cheap fertilizer. The amount of the sewage sludge dose used in agriculture to fertilize crops is determined by law and its application should be in accordance with the rules of the EU. The problem is to determine the rate of release of nutrients from sewage sludge and intake speed of these components by the plants. The aim of this study was to evaluate the agricultural use of sewage sludge in the year of application and its residual effect in maize grown for silage. Maize variety 'PR39G12' was grown in the field after 5-year monoculture. Experiments were carried out according to the scheme: the control without sewage sludge (mineral fertilizers); sewage sludge the year of application, sewage sludge the first year after application; sewage sludge the second year after application. Sewage sludge was applied in the spring at a dose of 10 tonnes D.M.· ha^-1, which was tested both in terms of microbial and heavy metal content. The amount of sewage sludge applied dose was in line with the regulations of Minister of Environment at that time [Directive... 2002] which allows the use of sludge in applied amount once every 5 years. Years in which the study was conducted were characterized by high volatility of weather conditions. There were significant differences in the amount and distribution of rainfall and the considerable volatility in the course of temperature in different periods of plant development. In the two years of the study (2006 and 2008) on the treatments where sewage sludge was applied in the first year, a trend of fewer plant losses was noted compared with plants with mineral fertilizer applied. Below-cob leaf greenness index showed no difference between the plants grown on mineral fertilizers and municipal sewage sludge, but the use of municipal sewage sludge contributed to cob set up. On the treatments fertilized with sewage sludge, plant productivity as fresh and dry matter yield of total maize plants was higher than on treatments with mineral fertilization.