Two soil profiles at Kruszyn Krajeński near Bydgoszcz were studied at the paper. Characteristic of soils and their water properties were determined. Air temperature (t) values and rainfall amounts (P) in particular months of vegetation period (April–September) in 1997–2006 for the investigated area were given. The vegetation period was characterized by mean air temperature 14,4 °C, ranging in particular years from 13,4 to 15,2 °C. Rainfall total during the vegetation period amounted on average 283,4 mm, ranging from 177,5 to 377 mm. Potential evapotranspiration (Etp) amounts were also determined using Grabarczyk’s formula. Irrigation requirements under the considered soil-climatic conditions were determined according to the following Drupka’s proposal: rainfall total (P) in the vegetation period as well as potential evapotranspiration (Etp) and difference Etp – P. Irrigation is needed when rainfall is lower than 370 mm, Etp is higher than 515 mm, and difference Etp – P is higher than 150 mm. On the base of rainfall amounts in vegetation period it can be stated that in years 1997-2006 irrigation requirements have been occurred in 8 seasons, and in two remaining years irrigation also could be needed because rainfall amounts were slightly higher from 370 mm (only by 4 and 7 ...
Reduction of evapotranspiration due to soil water deficit is quantified by CDI (Crop Drought Index). It is an agricultural drought index. The relationship was examined between precipitation P and CDI for sugar beet in Kujawy region for different soils. Evapotranspiration reduction was estimated on the basis of model research conducted for the growing season of sugar beet (21.04–30.09) in the years 1954–2003 and for 4 soils, with different total available soil water (103, 137, 165, 203 mm) in the 1-m profile. Relations between P and CDI were studied in 5 time periods, created by adding another subsequent phenological phases of sugar beet. The significance of the relationships was evaluated by using statistical analysis. The correlation coefficients showed the share of precipitation in the reduction of evapotranspiration of sugar beet in relation to potential evapotranspiration. The determined monograms can be useful in determining CDI on the basis of current measurements of precipitation. ...
The data on sugar beet yield were taken from Stations of Cultivar Assess-ment situated in south-west Poland. Using the method of multiple regression with interactions, models of root and leaf yield and sugar content percentage were con-structed, where the independent variables were precipitation total in the periods April-June and July-September or the number of days with rainfall in the stated periods. The optimum for obtaining highest yields of beetroots proved to be the set of factors: rainfall April-June 222 mm (the highest studied) and rainfall July-September 260 mm (a bit higher than average). As regards the number of days with rainfall, the optimum values were 35 days in the period IV-VI (values lower than average) and 50 days in VII-IX (value close to the maximal studied). The yield of roots was lowest with the lowest precipitation totals in both the periods (122 and 152 mm), and also when the highest number of days with rainfall in the spring season (46) was accompanied by low number of days with rainfall in the summer period (33). For the yield of leaves the best set of factors proved to be the maximum precipitation totals studied, both those of the spring and summer period ...
The paper presents the production effects of irrigation of sugar beet, winter rape, spring barley, soybean and faba bean, obtained in long-term (2005-2020) field experiments. The experiments were carried out on light soil with compact subsoil in the Bydgoszcz area. Significant, rectilinear relationships were found between increases in plant yields under the influence of sprinkler irrigation and precipitation totals in the vegetation periods of these plants, especially in the phases of increased water demand. The average long-term production effects of irrigation of the surveyed crops, which are presented in the work and their variability over the long-term period, may be the basis for assessing the desirability of irrigation of plants in areas of comparable soil and precipitation conditions. ...
