This work presents the evaluation of resources and quality of organic matter in arable luvisols of the Siedlce Upland. This was performed based on determination of organic carbon content and fraction composition of organic matter as well as of quantitative analyses of humic acids in humus horizons of twelve soil profiles. In the studied humus horizons a number of features were found indicating the lack of ability to accumulate considerable amount of humus. Organic matter resources amounted to 4.67-9.90 kg·m^-2 and correlated with the value of pHKCl and content of clay fraction. Even fraction composition of organic matter was found. Humic substances (extracted with 0.1M NaOH) constituted about the half of organic matter resources and were characterized by predominance of humic acids over fulvic acids. Proportion of humic acids, amounting to about 1/3 organic matter resources, significantly positively correlated with the value pHKCl and the clay fraction content. Based on the elemental composition and spectrophotometric properties, similar properties of humic acids were found, rather low degree of their aromatization and a high degree of internal oxidation of particles.

Determining a proper level of nitrogen fertilization for new cultivars of winter wheat is of great importance with regard to this component’s effect on the grain yield height and its quality. The aim of the study was determination of the effect of doses and methods of nitrogen fertilization (soil and foliar application) on the grain yield, yield components, total protein content and chosen macro- and microelements in winter wheat grain. The field experiment with winter wheat cv. Rywalka, was carried out in seasons 2008/2009, 2009/2010 and 2010/2011 on a farm located in the south-east Poland. The experiment was set up with the use of a randomized block design in four replications. The studied factor were diverse doses of nitrogen top-dressing from 40 to 120 kg·ha^-¹, soil and foliar application, compared to the control without nitrogen fertilization. The field experiment was set up on a brown soil, bonitation class IIIa. Within the years of research, the soil indicated a variable content of available mineral components. Soil reaction in KCL was from 5.9 to 6.7. Weather conditions during wheat’s growing season were variable in the years of research. The growing season 2009/2010 abounded in rainfall, of which the total amount was 950 mm from October to August. Growing seasons 2008/2009 and 2010/2011 were characterized by a favorable course of weather conditions. Winter wheat yield cv. Rywalka was diversified within the years of research, and depended on the top-dressing with nitrogen. The highest yield was obtained after an application of nitrogen at a dose of 120 kg·ha^-¹. Top-dressing with nitrogen affected some yield components of winter wheat. Plants fertilized with 120 N kg·ha^-¹ were characterized by a significantly higher spike density. Along with higher doses of nitrogen fertilization, also the total protein content increased in the grain. It was significantly higher after an application of 120 kg·ha^-¹ as well as 84 kg·ha^-¹, than in the grain of plants which were not fertilized. Top-dressing with nitrogen modified the content of magnesium and calcium, however, it had no significant effect on the accumulation of phosphorus and potassium in wheat grain. Under the effect of top-dressing with nitrogen, the content of manganese and zinc in the grain underwent oscillations, while the content of iron and copper was not significantly diversified.

This work presents the results of the study conducted in 2004-2006 at the Agricultural Experimental Station (RSD) in Zawady of the University of Natural Sciences and Humanities in Siedlce, concerning the effect of the ridge shape and harvest time, determined by the soil temperature, on the total and commercial tuber yield of potato. Analysis of results was carried out based on a three-year three-factorial (factor A – cultivar, factor B – soil temperature during harvest, factor C – ridge shape) field experiment established in split-split-plot design. Environmental conditions during the growing period played an important role in affecting the most of studied features of potato. The cultivar Sante gave the highest yields, whereas the cultivar Żagiel was characterized by the highest commercial yield. Ridge shape had a significant effect on the quantity of commercial yield. At growing potato in a typical ridge (20 cm in height) commercial yield was the highest. Another important factor was the time of harvest, which in parabolic way determined the total tuber yield.

This work presents the results of the study on the effect of ridge shape (the height of ridge) and harvest time, defined by the soil temperature, on the yield structure of three table potato cultivars. Analysis was performed based on three-year results (2004-2006) obtained from the experiment established in the split-split-plot design at the Agricultural Experimental Station in Zawady of the University of Natural Sciences and Humanities in Siedlce. Irrespective of the cultivar, tubers with a diameter from 50 to 60 mm constituted the largest proportion in the total yield, while the smallest tubers of the fraction below 30 mm. Harvest time had a significant effect on the weight of small tubers fraction with a diameter to 30 mm and from 30 to 40 mm. ridge shape significantly modified the yield of tubers with a diameter from 50 to 60 mm. Significantly higher tuber yield was obtained from the typical ridge (with a height of 20 cm), than from the high ridge (24 cm). The yield of large tuber fraction, above 60 mm, depended only on the weather conditions prevailing in the growing season.

Polish agricultural management is dominated by the ploughing system, which is characterized by a high labor- and energy consumption. Economical and ecological aspects make farmers search for alternative tillage systems. They consist in replacing ploughing with cultivating measures which do not overturn the soil or in total omission of tillage (direct sowing). The aim of the study was determination of the effect of tillage systems and level of mineral fertilization on the grain yield as well as on chosen structural components of the yield and winter wheat stand. Field experiments were carried out in the years 2003-2006 on lessive soil formed from loess. The experiment included various tillage systems: A – conventional tillage (control): skimming 8-10 cm + double harrowing, presow ploughing (18-20 cm) + harrowing; B – reduced tillage: single pre-sow ploughing (to 15 cm) + harrowing; C – reduced tillage: disking + harrowing, cultivating + harrowing. The second experimental factor were levels of mineral fertilization: a – 135.5 kg NPK per 1ha (N – 60; P – 17.4; K – 58.1), b – 203.4 kg NPK per 1 ha (N – 90; P – 26.2; K – 87.2). Winter wheat was cultivated in a four-field crop rotation: potato – spring wheat – field peawinter wheat. Research presented in this paper concerns the second cycle of crop rotation. Reduced tillage significantly decreased the grain yield in winter wheat, compared to the conventional ploughing system. Replacing ploughing with cultivating and harrowing affected a significant decrease in the plant height and spike density per 1 m² of winter wheat. Higher level of mineral fertilization increased the grain yield on average by 0.3 Mg·ha^-1. The study did not indicate any significant effect of tillage system and levels of mineral fertilization. In the second cycle of crop rotation, an increase in the grain yield was observed on all experimental plots, as well as in most structural components of the stand and winter wheat yield, compared to the one obtained in the first rotation.

Polyamines are widely involved in biological processes in plants including growth and development, as well as in the response to stress. However, the interpretation of polyamine participations in the induction of flowering of winter plants, and, hence, the possibility of their exogenous application to accelerate flowering, is ambiguous. Winter plants require prolonged exposure to low temperatures (vernalization) to induce the generative development, thus the changes in the levels of these substances may also result in low-temperature-stress symptoms. The aim of this work was to check, whether the increase of polyamines is actually connected with flowering of winter rape plants (cv. Górczański). To exclude the vernalization effect, vegetative apexes of winter rape were grafted onto generative plants. The content of polyamines: putrescine, spermidine and spermine was measured, using high- performance liquid chromatography, in the apical parts and the youngest leaves of grafted apexes during 1-4 weeks after grafting. For comparison of the changes in the levels of polyamines occurring during vernalization, apexes and the youngest leaves were collected from winter rape after 1-8 weeks of culture at 5°/2° C. In apexes, content of all polyamines increased at 2 week (putrescine) or 2-3 weeks (spermine and spermidine) and in the period of 5-8 weeks of vernalization. For putrescine, the maximum increase was detected during at the 6^th week and for spermidine and spermine during the 7^th week of cold treatment, i.e when approximately 60-90% of plants were in the generative phase. In leaves, the changes of polyamines composition occurred almost during the same periods as in the apexes. Confirmation of the involvement of polyamines to flowering induction was the increase of these substances observed during generative development of grafted non-vernalized apexes. The registered increase of polyamines concentrations in the first weeks after veranlization (2-3 weeks) was probably connected with the cold-stress response of rape plants.

The content and profile distribution of lead in exchangeable (F1), reducible (F2), oxidizable (F3) and residual (F4) fractions, separated according the BCR sequential procedure in cultivated Stagnic Luvisols of Siedlce Upland was examined. Natural total content of lead was found in the soils, and its profile distribution resulted mostly from the abundance of parent material and advancement of the soil formation of lessivage process. Mean percentage of lead in green fractions with the BCR method presents the following series of decreasing values: F4 > F2 > F3 > F1. The most lead in fractions F1 and F3 was recorded in surface horizons (Ap, EB); F2 – in the enrichment horizon (Bt); F4 – in the parent material horizon (C, Ck). Significant effect of soil properties (pH, Corg, clay fraction, KPW, Pbt) was indicated on the lead content in separated fractions. Accumulation of lead in humus horizons, including its percentage in readily soluble bioavailable fraction F1, is a result of a small but long lasting anthropopressure, which does not limit agricultural use of the studied soils to production of high quality agricultural products.

The use of semi-dwarfing genes resulted in a significant improvement in wheat breeding. Of the 21 genes that condition straw shortening described in literature, Rht8 is one of the most widely used in wheat breeding programmes. This gene is located on the short arm of chromosome 2D within 0.6 cM from locus 261 Xgwm. Its presence can be identified only with the use of molecular methods, which include, among others, the SSR technique (Single Sequence Repeat). This technique makes it possible to generate products with the length of 165 bp, 174 bp, and 192 bp. Their presence indicates the occurrence of the gene Rht8 in the analyzed genotypes. The product of 192 bp in length is the most strongly associated with the reduction of wheat plant height and decreases height by about 7-8 cm. The aim of the work was to identify the semi-dwarfing genes for the presence of marker WMS 261, 192 bp in length, linked with Rht8, of wheat of different origin. Plant material consisted of 27 cultivars and nine lines of wheat. The study included Polish, Russian, Czech, Austrian, French, and English cultivars and Polish lines from Smolice Plant Breeding and from The Department of Genetics and Plant Breeding of The University of Life Sciences in Poznan. As a result of the conducted analysis, the presence of the specific product was found in 17 out of the 36 tested genotypes. They were Polish cultivars Grana, Kompana, Luna, Małgorzatka Udycka, Ostka Strzelecka, and Turnia and foreign cultivars Alcazar, Besostaja 4, and Ludwig. The presence of marker WMS 261 with the length of 192 bp was also found in three lines from Smolice Plant Breeding and in two lines from The Department of Genetics and Plant Breeding of The University of Life Sciences in Poznan.

The aim of the study was the evaluation of the economic and energy efficiency of spring barley cultivation depending on the applied pesticides. The incurred costs of plant protection treatments affected the obtainment of higher grain yield, the value of which increased by over 660 PLN·ha^-1. Every chemical treatment generated additional yield increase, which resulted in the improvement of the profitability index. It was demonstrated that the possibilities of cost reduction apply mostly to tractor and machine expenditures. As far as energy consumption is concerned, in spring barley production, costs of fertilizers had the highest share (on average 50.1%), followed by diesel fuel (23.9%), whereas energy expenditure for plant protection made up a small part of energy purchase (0.6%). It was also demonstrated that the application of complex protection resulted in the highest production effect. Expenditure increase by 140 PLN·ha^-1 (10.26%) resulted in yield value increase by 965 PLN·ha^-1 (19.36%).