Effectiveness of insecticide protection of very early edible potato cultivars against potato beetle was assessed in the years 2005-2006. The research used Prestige 290 FS, Regent 200 SC and Spruzit 04 preparations, as well as Beauveria bassiana entomopathogenic fungus spore suspension. The selection of preparations for potato beetle control significantly diversified the amount and structure of potato tuber yield. Average total tuber yield on the control, without insecticide protection, was 30.3 t∙ha^-1, whereas on the treatments where Spruzit 04E C and B. bassiana spore suspension were applied the yield was on the level of 36 t∙ha^-1, whereas potatoes protected by chemical preparations Regent 200 SC and Prestige 290 FS produced the largest yields, respectively on the level 41.0 and 41.8 t∙ha^-1. Potato beetle control in potato cultivation contributed to an increase in average tuber weight and the share of big tuber fractions in the yield. A significant rise in the marketable tuber fraction was registered only on treatments protected with B. bassiana spore suspension and by Prestige 290 FS preparation.

On the basis of the field experiment carried out at the Experimental Station at Jadwisin (52^o29’ N; 21^o03’ E), Polish mid-early potato cultivar Triada was grown on sandy loam in years 2004 and 2005 in 6 treatments, which included the application of water and nitrogen: organic (cattle manure) and mineral. Water drip irrigation and nitrogen fertigation were scheduled by the Decision Support System (DSS). Diverse water supplies and organic or mineral nitrogen did not change harvest index (HI) values, which varied between 0.7 and 0.8 at the end of the growing period. Average tuber dry matter yield, about 11.0 t∙ha^-1, in both years of the investigation was reached with different HI values: 0.78 for 2004, and 0.73 for 2005. Higher percentage of biomass distributed to tubers was found in 2004, which was characterized by lower cumulative thermal time and global radiation, as well as better water balance in comparison with the growing period of 2005.

Basis of the study was made up of the results of automatic, hourly measurements of air temperature and bare soil temperature originating from the agrometeorological station in Lipnik (53^o21’ N; 14^o58’ E, 30 m AMSL) from the period of 2001-2005. Basing on the results of the linear regression analysis, relationships for particular months were determined between daily soil temperature at four depths and air temperature set in seven different combinations. It was stated that the highest possibilities of daily soil temperature prediction in profile to 50 cm are characteristic for the air temperature that is the average from 24 hourly measurements. Average absolute differences between the actual soil temperature and the one calculated from equations for this relation oscillate in the particular months between 1.3^oC at the depth of 5 cm and 0.5^oC at the depth of 50 cm. On average, the smallest differences apply to the warm half of the year and the depth of 50 cm. It was shown that significantly smaller possibilities of the estimation of daily soil temperature values are characteristic for daily air temperature amplitude.

The aim of this study was to estimate the susceptibility of a tuft (ssp. commutata – cultivar Mirena) and creeping (ssp. rubra – cultivar Nista) forms of Festuca rubra to infestation by pathogenic fungi and the effect of chemical protection on the health of plants grown for seeds. The study was conducted in 2004-2006 (first series) and in 2005-2007 (second series) at the Experimental Variety Testing Station in Chrząstowo (53°09’ N; 17°35’ E). Fungicides containing azoxystrobin, prochloraz and propiconazole were applied for protection against fungal pathogens. The assessment of disease symptom intensity was conducted in the summer and autumn periods based on modified scales by Birckenstaedt et al. [1994]. In the establisment and production years we found a moderate infestation of red fescue of the cultivars Mirena and Nista by pathogenic fungi. Highest values of leaf disease index at a level of DI = 16.9% were registered in the case of leaf spots. Occurrence of rust and powdery mildew stayed at a lower level. Presence of Microdochium nivale was registered sporadically. Higher susceptibility of the creeping cultivar Nista to infestation by fungi causing leaf spots and powdery mildew was observed. In the vast majority of cases applying chemical protection significantly decreased a degree of plant infestation in the summer period.

In 2005-2007, in the field experiment, the yield and quality of summer savory herb of Polish cultivar Saturn in organic farming were tested. The experiment was established on six organic farms and one conventional farm in different localities in Poland. The following features were evaluated: fresh and dried herb yield, stem fraction in herb, seed yield, weight of 1000 seeds, essential oil content, macro- and microelement content, nitrate content and microbiological purity. Only from Słońsk savory herb yield was higher compared with the yield from conventional cultivation though it contained high amount of stems. Organic savory herb was characterized by high content of essential oil and increased content of macro- and microelements. Evaluation of microbiological purity showed that herb contamination from both types of cultivation did not exceed standard for raw materials treated with hot water.

In 2005-2007, in the field experiment, the yield and quality of sweet marjoram herb of Polish cultivar ‘Miraż’ in organic cultivation were tested. The experiment was established on six organic farms and one conventional farm in different localities in Poland. The following features were evaluated: fresh and dried herb yield, stem fraction in herb, seed yield, essential oil content, macro- and microelements content, nitrate content and microbiological purity. Organic marjoram herb yield only from one farm (Słońsk) was higher compared with the yield from conventional cultivation, though this herb contained high amount of stems. There were no seeds collected or the seed yield was very low in both organic and conventional farming. Both marjoram herbs, organic and conventional from Plewiska had similar quality (essential oil, macro- and microelements and nitrate content). Evaluation of microbiological purity showed that herb contamination from both types of cultivation did not exceed standard for raw materials treated with hot water.

Field experiments were conducted in two localities: Prusy (50°07’ N; 20°04’ E – one experiment) and Wierzbica (50°29’ N; 19°45’ E – two experiments) in 2003. The objective of this study was to analyse the influence of agronomic factors on the grain yield and on the content of macroelements in grain of different forms of naked oat. In Wierzbica the grain yield was determined statistically by the genotype, the phosphorus and potassium fertilization and the application of the plants growth regulator Moddus. In Prusy grain yield was determined only by the genotype (cultivars, strains). A concentration of macroelements in forms of oat was statistically different. In both localities the phosphorus and potassium fertilization and foliar application of urea, in general, had not the statistical influence on the content of the macroelements. An exception is the influence of the foliar application of urea on the content of potassium. Plant growth regulator Moddus caused changes in the content of macroelements. These changes were not always statistically significant, but always increased the concentration of macroelements. The second plant growth regulator Promalin did not cause changes in the concentration of macroelements.