The aim of this study was to determine the quality of flour, dough and bread made from the grain of winter wheat grown in a continuous cropping system or after oil plants (winter rapeseed, spring rapeseed, white mustard, brown mustard) in production systems of different intensity. The above products, obtained from wheat grain harvested in three growing seasons (2006/2007, 2007/2008, 2008/2009), were analyzed to determine the whiteness, ash content and water absorption capacity of flour, the development time, stability, softening, resistance, extensibility and energy of dough, and the baking volume and yield of bread. The grain of winter wheat grown in a continuous cropping system produced whiter flour with a lower ash content than the grain of winter wheat plants grown after oil plants. The intensification of wheat grain production contributed to flour darkening and a decrease in flour ash content. Monoculture had no adverse effects on the water absorption capacity of flour, the development time, stability or softening of dough. Intensification of production improved water absorption of flour, the development time, stability and softening of dough. The extensibility and energy of dough made from flour obtained from wheat grown in a continuous cropping system were substantially lower, compared with wheat grown after winter rapeseed. Intensification of production also improved dough extensibility and energy. The resistance of dough made from wheat grain produced under medium-input technology was significantly lower, compared with grain produced under low-input technology. Intensification of wheat grain production contributed to a greater increase in the yield of bread made from winter wheat grown after oil plants (primarily winter rapeseed and brown mustard), compared with monoculture.

Three-factorial field experiment on agricultural practices in spring wheat cultivation in short-term monoculture was conducted in the years 2012-2013 in Chełmce (52^o61’ N; 18^o44’ E), on the soil of a good rye complex. The experimental factors included: A – tillage method connected with the application of organic matter (five variants with a post-harvest tillage with a grubber and pre-winter plough or without ploughing, and with the use of manure and stubble catch crop biomass – white mustard), B – method of application of post-harvest residues (four variants with the use of straw and effective microorganisms or without), C – application of a biostimulant Asahi SL (two levels). The aim of the study was determination of the effect of these factors on the yield components and grain yield in spring wheat cultivated in the 2^nd and 3^rd year of monoculture. Grain yield of spring wheat in the first year of research was by 25% higher than in the second year, which to some extent confirms low tolerance of this plant to being cultivated after itself. In the spring wheat monoculture, especially in the third year, grain yield was beneficially affected by the application of manure mixed with soil with a grubber and pre-winter plough, as well as manure and biomass of white mustard mulching the field through winter with tillage reduced to grubbing. The yield-producing effect of shredded straw with an inoculum of effective microorganisms applied into the soil manifested itself only in the initial period of monoculture, the second year, and with no manure application. In case of organic fertilization as well as in the subsequent year of monoculture, the use of straw and effective microorganisms did not affect beneficially the grain yield. Biostimulant Asahi SL, however, caused increase in the grain yield, especially in the third year of spring wheat monoculture and after using manure.

In a pot experiment, carried out in three series in years 2010-2012 at the greenhouse laboratory of the University of Warmia and Mazury in Olsztyn, the effect of Persian clover undersown and plant density on the morphological characteristics of spring wheat was evaluated. Experimental factors were as follows: I) spring wheat (Triticum aestivum ssp. vulgare L.) sowing method: pure sowing and with Persian clover (Trifolium resupinatum L.) undersown, II) density of both species in agreement with the recommendations of agrotechnics (called “higher” in the present work) and lowered by 20% (called “lower”). In the pots of 22 cm in diameter, the following plants were sown: in the pots with higher density, 19 spring wheat grains and 12 seeds of Persian clover, and in the pots with lower density, 12 wheat grains and nine clover seeds. Measurements were undertaken at the following developmental stages of wheat (the BBCH scale): leaf development (12-14), tillering (21-23), straw shooting (31-32), earing (54-56), and ripening (87-89). The studied factors were: plant height, root length, number of straws per plant, leaf parameters (area, length, and width), spike parameters (length, grain number, and mass), and grain yield per pot. The studies demonstrated that undersown diversified plant height and straw number in spring wheat. Its roots in the combination with clover were shorter than in pure sowing only during earing. In the presence of undersown, wheat developed fewer leaves (by nearly 10%), shorter spikes (by 10%) with fewer grains (by 15.7%) of lower mass (by 28.6%) and smaller yield (by 29.7%). Sowing method, depending on the developmental stage, differently affected leaf parameters. Plant density had no effect on the scope of the differences between pure and mixed sowings in the morphology of the vegetative above-ground parts and roots of spring wheat. In the pots with higher density, mixed sowing limited spike length and grain number and mass more than in the pots with lower density.

Cthe aim of this study was to determine the effect of the cultivar and mineral fertilization, taking into consideration the use of ash from wheat straw, on biomass production of winter oilseed rape. Also changes in pH value and the contents of forms of macroand microelements available for plants in typical lessive soil after three years of using different rates of ash from winter wheat straw was assessed. In 2010-2012 at the Research Station in Mochełek, belonging to the University of Technology and Life Sciences in Bydgoszcz made tripartite experience, which has been studied interdependent interaction of diverse nitrogen-phosphorus fertilization (90 kg N + 15,3 kg P·ha^-1; 90 kg N + 30,6 kg P·ha^-1; 180 kg N + 15,3 kg P·ha^-1; 180 kg N + 30,6 kg P·ha^-1) and the impact of ash from winter wheat straw (0; 0,25; 0,5; 0,75 i 1,0 Mg·ha^-1) of biomass production of two cultivars of winter oilseed rape (SW Gospel, Ekstend F1). The study found that the productivity of hybrid rape Extend F1 was higher than the population cultivar SW Gospel. Increased biomass production, especially post-harvest residues, such qualifies for cultivation in the conditions of straw management on non-agricultural purposes, as a potential source of soil organic matter. High biomass production of winter rape, including post-harvest residues, require high nitrogen fertilization. If the soil is rich, it is possible while limiting phosphorus fertilization. The ash from wheat straw, supplemented by nitrogen fertilization and phosphorus, used at a dose of 1.0 Mg·ha^-1 impacted favourably on seed yield and straw of winter oilseed rape, and also allowed after three years of application to keep without significant changes in soil pH and the content in it available plant macro-and micronutrients.

The work presents data from nine Institute of Meteorology and Water Management (IMGW) stations collected from 1971 to 2005 in central-east Poland. The relative precipitation index (RPI) was applied to determine the frequency of individual drought classes during the growth period. Moreover, spatial distribution of precipitation amounts in the study area was presented. Also, the direction and significance of tendency for changes in precipitation were presented. In the study years, monthly precipitation amounts varied greatly during the growth period in central-east Poland. The lowest precipitation sums (335 mm) during the growth period (April-September) were recorded in the south-western part of the study area, whereas the highest precipitation sums (367 mm) were found in the north-eastern part of the area. The highest long-term (1971-2005) average precipitation amounts were recorded in July (74 mm) and June (72 mm), and the lowest ones in April (38 mm). Analysis of the frequency of individual drought classes according to the relative precipitation index showed that typical months were three and six times as frequent as extremely dry and wet months, respectively. Severe droughts occurred the most frequently in June and April; very dry and very wet spells were noted in April, and extremely wet periods in July. Analysis of the slopes of the regression line representing the rate of change in precipitation sums during the study period showed that the values of the slopes were close to zero and statistically insignificant. Statistically significant changes were recorded only in June in Białowieża, where the monthly precipitation amount decreased by 17.4 mm/10 years, and in August in Legionowo and Pułtusk, where the respective declines amounted to 13.5/10 years and 9.9 mm/10 years.

The most often used substrate in agricultural biogas plants is maize. Due to an increase in the area of maize acreage and the necessity of use proper crop rotation in the plant cultivation, alternative raw materials should be looked for. Apart from the high biomass yield, alternative plants for biogas production should be characterized by a favourable energy efficiency index. The favourable value of this index can be obtained by reduction of energy outlays incurred for biomass production and high energy efficiency in the yield. The aim of this study was to compare the yield and energy efficiency of biomass production of some species of plants grown under different conditions of energy outlays. The study was conducted in the years 2009-2011 at the Production and Experimental Station at Bałcyny near Ostróda (53°35’ N; 19°51’ E) of the University of Warmia and Mazury in Olsztyn. The study was based on the strict two-factorial experiment established in soil of 4. soil agricultural suitability complex, where three plant species were compared (maize cv. LG 2244, sorghum cv. Sucrosorgo 506, Virginia fanpetals) cultivated according to two technologies – high-input (intensive) and medium-input (with reduced outlays for means of production in relations to the intensive technology). Among the studied plants, the highest efficiency of biomass (21.4 Mg⋅ha^-1 d.m.) and energy in yield (390 GJ·ha^-1) and the most favourable index of energy consumption per unit (1.02 GJ·t^-1) and energy efficiency (18.4) were provided by maize. Sorghum and Virginia fanpetals gave significantly lower yields than maize (by 40 and 54%, respectively) and were not equal in respect of energy discriminants in yield, energy consumption per unit or energy efficiency. The high-input technology provided a significantly higher biomass yield on average for 3 studied species (15.8 Mg⋅ha^-1 d.m.) than medium-input (13.6 Mg⋅ha^-1 d.m.). In the medium-input technology, reduction in energy outlays by 27%, mainly of mineral fertilization, caused a significant decrease in biomass yield by 14%, but it provided a higher energy efficiency of its production (15.3). The most favourable energy efficiency index of biomass production was obtained by maize cultivated in the medium-input technology (19.7). Lower energy assessment value of sorghum and Virginia fanpetals does not eliminate possibility of using the biomass of these plants as supplementing substrates for biogas production.

Quick and uniform emergence is one of the factors determining height and stability of the yield of cereals, especially of their spring forms. Thus, it is relevant to learn about the effect of fractionation of the seed material of spring wheat and spring rye. Over the years 2004-2009 two series of microplot experiments were conducted, whose aim was to determine and compare the effect of seed grain fraction on growth and yield of spring rye cv. Bojko and spring wheat cv. Monsun, as well as evaluation of the response of spring rye to seed grain size depending on the sowing date. The experimental factors for spring rye included: A – sowing date (optimum and delayed), B – seed grain size (fractions: >2.8 mm, 2.5-2.8 mm, 2.2-2.5 mm). The factor for spring wheat was seed grain size with levels analogical as for spring rye. The value of the yield components and the yield of grain and straw of spring rye, as well as of spring wheat from the fraction >2.8 mm were generally higher than from the smallest grain 2.2-2.5 mm. Large plump seed grain had a greater significance for the yield of spring wheat than that of spring rye. The use of a grain smaller than 2,8 mm for sowing caused a greater reduction in its ear density and yields of grain and straw compared with spring rye. An unfavorable effect of using a small grain for sowing, fraction 2.2-2.5 mm, on 1000 grain weight of spring wheat manifested itself especially with the delayed sowing date. Delay in sowing rye resulted in a decrease in plant density after emergence, grain number per ear, grain weight per ear, 1000 grain weight, and in the yields of grain and straw.