In the years 2003-2005 the quantity and structure of grain yield of nine spring wheat cultivars were assessed. The wheat was cultivated on two agrotechnical levels under soil conditions of a very good wheat complex. The agrotechnical levels comprised medium intensive and intensive technology which differed in nitrogen dose and application or no application of a retardant and fungicides. The quantity of spring wheat grain yield was significantly dependent on the year of cultivation, intensity of the technology and the cultivar. Average grain yield of the analyzed spring wheat cultivars cultivated on the higher agrotechnical level was 9.34 t∙ha^-1 and was almost 11% larger that the yield obtained from medium intensive cultivation. In the group of the investigated cultivars, Żura produced the largest grain yield, on average 9.64 t∙ha^-1, whereas the other cultivars were yielding between 7 and 14% lower. The cultivar factor and the weather conditions significantly diversified the value of all elements of the grain yield structure, while the effect of technology intensity was apparent only for the number of ears per area unit.

Natural importance and economical and usefulness values (FVS) of meadows situated in the valley of the central Mogilnica River were assessed. The natural value was determined on the basis of: the number of species in a phytosociological relevés, phytosociological structure, floristic diversity expressed by the Shannon-Wiener index (H’) and the method of plant community valorization according to Oświt. Site conditions: moisture (F), soil reaction (R), soil nitrogen content (N) of the examined meadow communities were evaluated using the Ellenberg phyto-indication. Both natural and usefulness values of the examined communities depend on the place of occurrence in the valley. The communities situated closest to the river, which were assigned to the class of Phragmitetea, developed in their typical forms and presented significant and moderately significant natural values, although their sward was found to be characterized by low usefulness value. Communities growing further from the river, representing the Molinio-Arrhena-theretea class, are utilized at the present time. Grasses found in these communities are of moderate natural importance but the meadows provide high yields of good fodder value.

The study aim was the assessment of energy efficiency in the two-course rotation: fallow – winter wheat. The assessment was made on the grounds of a field experiment conducted at the Experimental Station Bałcyny of the University of Warmia and Mazury in 2003-2006. The forecrops for the winter wheat were the black fallow, the herbicide treated fallow and three variants of the green fallow with white mustard, Persian clover, and Italian ryegrass. It was determined that the highest energy outlays were incurred in maintaining the black fallow ad the lowest in case of herbicide fallow. Among the compared two-field segments of rotation the highest energy efficiency indicator (8.2) was characteristic for the system of Persian clover – wheat offering at the same time the lowest energy outlay for production of 1 cereal unit. The lowest energy efficiency indicator (5.4) was recorded in the rotation segment of Italian ryegrass – winter wheat.

The rate of photosynthesis and transpiration, intercellular CO₂ concentration, and stomatal conductance of two cultivars of winter wheat were determined in the study. The severity of fungal infection of the grain was also estimated. It was found that water deficit decreased the values of gas exchange parameters, biometric characters and grain weight. In the first year the number of fungal isolates in wheat grain of both cultivars was lower under water stress conditions. However, in the next year the findings were ambiguous.

The strict 2-factor field experiment was carried out over 2005-2007 at the Mochełek Experiment Station of Bydgoszcz University of Technology and Life Sciences. Three pea cultivars, namely ‘Kolia’, ‘Wenus’ and ‘Winerek’ were cultivated according to four technologies: extensive, low-input, moderately intensive and intensive differing in the use of industrial means of production. LAI, chlorophyll content in leaves and yields of total biomass and seeds were not affected by different input of industrial production means used in low-input and intensive technologies. In spite of quite different moisture conditions over growing periods, in generative phase especially, pea cultivars yielded similarly. Semi-leafless ‘Wenus’ cultivar showed lowest, while traditional ‘Kolia’ and ‘Winerek’, highest and similar LAI. Harvest index in extensive and low-input technologies as well as in low-input and intensive technologies was statistically similar. The technologies used differentiated neither the harvest index nor chlorophyll content and seed yield in cultivars tested.

The current paper reports about the influence of different levels of fertilization and agricultural practices (i.e. shallow and deep ploughing) on the total content of potassium (K_tot) and its forms in a soil formed from post-mining lands after twenty seven years of land reclamation processes. The total content of potassium ranged from 11630 to 15890 mg K·kg^-1. It was found that the content of all potassium forms increased in soils along with the level of fertilization and varied within the range between 16.45 and 82.53 mg K·kg^-1 for water-soluble K; between 75.51 and 210.93 mg K·kg^-1 for active K extracted by 0.01 mol·dm^-3 CaCl₂; between 83.56 and 233.42 mg K·kg^-1 for available K determined by the Egner-Riehm method; between 177.24 and 403.86 mg K·kg^-1 for retrograded K extracted by 2 mol·dm^-3 HCl; between 1001,2 and 1765,0 mg K·kg^-1 for the reserve pool of K assayed by 1 mol·dm^-3 HNO₃; and between 1801 and 2817 mg K·kg^-1 for residual K dissolved in a 20% HCl solution. No significant differences occurred for the same fertilization treatments under shallow and deep ploughing practices.

A field experiment with perennial ryegrass (Lolium perenne L.) grown for seed was conducted in Mochełek, at the Research Station of Agriculture Faculty of University of Technology and Life Sciences in Bydgoszcz. The aim of the study was to analyse the effect of nitrogen fertilization doses and the length of use of perennial ryegrass lawn cultivar grown for seed on biological characters, their variation and interrelationship. Forming numerous and relatively long tillers and ears, as well as well-formed flag leaves, resulted in increasing seed mass per ear and seed yield. Every additional 30 kg N·ha^-1 within the range from 0 to 90 kg·ha^-1 stimulated production of seed mass per ear. Increasing the dose from 30 to 60 kg N·ha^-1 affected the growth of tiller number and ear length, and the next 30 kg N·ha^-1 increased the length and width of flag leaf blade. Plant ageing was accompanied by decreasing tiller length, seed mass per ear, the length of tillers and ears. Of biological characters tested, the number of tillers showed the highest variation, and the length of use had three times more influence on the variety of this character than nitrogen fertilization level.

The aim of the present research was to determine the survival rate and the rate of inactivation of indicator bacteria Salmonella Senftenberg W₇₇₅ in soil, depending on the cultivation of selected agricultural crops. The research was carried out over 2005-2006 at the UTP Experimental Station at Mochełek. In the experiment the role of the carrier of Salmonella Senftenberg W₇₇₅ bacilli was played by communal waste compost introduced into the soil environment, on experimental plots with agricultural plantation of oat, mixture of oat with yellow lupine, spring rye and a mixture of spring rye with yellow lupine. The present research demonstrated that the weekly elimination rate of Salmonella Senftenberg W₇₇₅ in soil, depending on respective field crops, ranged from 0.33 to 0.46 log, while the maximum survival time of detectable microorganisms – from 18 to 24 weeks.

Assessment of weed infestation in winter wheat, winter triticale and spring barley cultivated since year 1998 in cereal crop rotation under three technologies varying in production intensity was conducted in years 2005, 2006 and 2007 at the Experimental Station Osiny (Institute of Soil Science and Plant Cultivation in Puławy). The degree of potential weed infestation (weed total dry matter per 1 m²) collected from areas protected against applied herbicides was evaluated, as well as herbicide efficacy. Generally, herbicide efficacy was very good or good. Potential weed infestation increased significantly as the intensity degree of production technology decreased. In 2006, the degree of potential weed infestation was generally much lower compared to 2005 and 2007 in particular under economical technology. In 2005 spring barley was the most infested by weeds and winter triticale was the least infested. In 2006, herbicide efficacy also was very good but generally all crops were less infested compared to 2005 and 2007. In 2007, winter wheat was the most infested by weeds, while spring barley was the least infested. The analysis of precipitation and monthly average temperature in spring does not give a logic answer why in 2006 weed infestation was so different compared to 2005 and 2007. Due to remarkable differences in potential weed infestation of tested crops grown under different technologies in 3-year period of study, it is impossible to give the final answer whether the changes in weed population and their total dry matter production depend on grain species grown under different cultivation technologies. It looks like the seed bank in soil is many times higher under economical production technology compared to intensive and integrated technologies.

The study was conducted on the basis of a multiannual static field experiment established in 1979. It was conducted in the 3-year simplified rotation system: potato – winter rye – winter rye. The study refers to an early, edible variety of Bila potato growing in the first year of 10^th rotation (2006). Experimental factors were the following: organic fertilisation (without manure and with manure 30 t·ha^-1), and nitrate fertilisation – four doses (0, 60, 120, 180 kg∙ha^-1). The aim of this study was to define the influence of organic and mineral fertilisation on selected qualitative properties of potato tubers. The results obtained from the study show a positive effect of manure and nitrate fertilisation on dry matter and starch content and a negative effect on sugar content. Increasing nitrogen doses lowered a content of vitamin C in potato tubers. However, potatoes growing on manure had a higher content of this ingredient.