In this studies, a plant water needs index was defined as an amount of rainfall, in the period of plant increasing water demands, which didn't increase a yield of an irrigated plants. Such defined optimal rainfall was calculated on the basis of results of long-term field experiments carried out on two kinds of soil in a region of Bydgoszcz. Irrigation needs understood as rainfall insufficiency in the period of plant increasing water demands, were calculated as a difference be-tween optimal and actual rainfall. Homogeneous rainfall data from years 1971-2005 in Mochełek (placed near Bydgoszcz) were used. Calculations of irrigation needs were made in the period of increasing water demands of the followed plants: spring cereals, medium-early potato and maize cultivated for grain. All of them were grown on two kinds of soil: a very light soil of permeable subsoil and a light soil of compact subsoil. Obtained results enabled to classify the evaluated irrigation needs. The criterions were: a number of essential individual water doses and a quantity of forecasted productive effects of the irrigated plants. Re-sults of the studies show that the irrigation needs calculated on a very light soil in the region of Bydgoszcz occurred in 87,7-97,1% (it ...
The research was performed to assess the direction, scope and significance of changes of thermal indices in agricultural seasons in the region of Bydgoszcz. Measurements of air temperature were carried out in a standard way, at the' Mo-chełek' Research Centre of the Faculty of Agriculture and Biotechnology UTP Bydgoszcz, located about 20 km from Bydgoszcz. The study included the normal period of years 1981-2010. The following agricultural seasons were taken into consideration: farming, growing, intensive plant growth, plant maturity and plant dormancy. The results of the research showed no significant trends among all 15 indicators characterizing the thermal agricultural seasons in the vicinity of Bydgoszcz over the years 1981- 2010. In some cases (5 of the 15) was confirmed a broadening of their temporal variability in the years 1996-2010, compared to the previous 15-year period 1981-1995. This may possibly be regarded as a symptom of the observed climate change. Long-term average values of the thermal indices in agricultural seasons examined during the period 1981-2010 were consistent with normative values for the region of Bydgoszcz quoted in publications, which characterize the Polish climate and agroclimate. It confirms the representativeness of the measurement point in Mochełek. The research confirmed a very high ...
