Changes in thermal and precipitation conditions in Poland in 1971-2010. The article presents changes in thermal and precipitation conditions on Polish territory in the years 1971- -2010 based on data from six meteorological stations (Koszalin, Olsztyn, Poznań, Lublin, Opole and Kraków). These data concern the monthly average air temperature, precipitation and the number of days with precipitation per month. Based on the analysis of changing trends in the study of meteorological elements, authors observed an increase in the mean annual air temperature of about 0.9°C over 10 years in all localities. In contrast, trends in the average monthly air temperatures were characterised by temporal and spatial variation. As a result of the increase in temperature, there was a change in the dates signifying the beginning and the end of the thermal periods: farming (OG), vegetation (OW), intensive vegetation (OIW) and maturation or thermal summers (OD/L). A tendency for these periods to start earlier was noted. Statistically significant changes were found for the following periods: vegetation in Koszalin and Olsztyn, intensive vegetation at all stations and thermal summer only in Lublin. An increasingly later end to these periods was noted, and statistically significant trends were found for the dates of the end of the following periods: maturation (thermal summer) at all stations except Opole, intensive vegetation in Poznań and Lublin and vegetation in Lublin and Opole. Seasonal and monthly precipitation totals in the years 1971-2010 were characterised by cyclicality. Significant upward trends were found only in the case of monthly precipitation totals in August in Koszalin and the sum of precipitation in the cooler half of the year in Poznań. In contrast, there was more days with precipitation at all stations included in the study, but the statistical significance of trends varied by location. Changes in thermal and precipitation conditions were accompanied by, among other factors, an increase in temperature, changes in the length of thermal periods and an increase in the frequency of rainfall. All of this is important information for the agricultural sector regarding changing crop conditions

The aim of this study was to determine, by use PCA analysis, the impact of meteorological elements on the PM₁₀ concentration on the example of the mountain valley. Daily values of selected meteorological elements, measured during a ten-year period in the spring, summer, autumn and winter, obtained from the meteorological station in Nowy Sącz, were adopted as variables explaining PM₁₀ concentration. The level of PM₁₀ was significantly affected by the maximum, minimum and average temperature in autumn, winter and spring. In summer the average and maximum temperature was significant. In winter, the first principle component mainly consisted of the combination of the average and maximum wind speed. The second principal component in spring, summer and autumn was the combination of the wind speed (average and maximum), but in winter humidity and atmospheric pressure seemed to be significant. The third principal component, in terms of strength of impact, was humidity in spring, the combination of humidity and minimum temperature in summer, and precipitation in autumn. In winter, the highest PM₁₀ concentrations were observed during the non-directional, anticyclonic wedge conditions. Three principal components were distinguished in this situation: temperature (average, maximum and minimum); the combination of humidity and wind speed and precipitation.

The aim of the study was to evaluate the effect of biostimulants enhancing plant growth and development, i.e. organic stimulator based on metal sulphates, Bacillus subtilis, humic acids, on the chemical composition and level of bioactive compounds in garlic leaves, stems, and bulbs. The study was conducted in three growing seasons on the ‘Ornak’ winter garlic cultivar. The propagating material was treated in solutions of the biostimulants and after emergence the plants were sprayed with the products three times. The most valuable edible organ proved to be the leaves, which contained the most protein, fat, and mineral components expressed as ash, were the richest source of fibre, vitamin C, and polyphenols, and also had the highest antioxidant activity among the organs tested. The nutritional value of the stems was comparable to that of the bulbs, and the level of polyphenols and antioxidant activity were even higher. The use of the growth and development biostimulants influenced the chemical composition of the garlic, but the effect was modified by the course of weather in different years of the research and also depended on edible organ. On average for years and organs all biostimulants increased the level of protein, minerals expressed as ash and enhanced antioxidant activity, whereas decreased the level of total carbohydrates.

Recent years have seen a significant increase in weather anomalies in Central Europe (51°22′ N, 22°64′ E), which makes it more difficult to predict yields of winter wheat and to estimate prices on world exchanges. Eight-year (2007–2015) field observations of winter wheat cv. Turnia were carried out in order to determine the relationship between selected meteorological indicators (e.g., the values of average daily air temperature, daily sums of precipitation, and the number of days with precipitation) and the biometric traits and seed yield of winter wheat. In addition, an attempt was made to identify the meteorological parameters that determine an increase in stem elongation during the growing season. The relationship between yield parameters and biometric parameters was evaluated using Spearman’s non-parametric correlation coefficients. The regression models for analysis of the dependence of yield parameters and biometric parameters on meteorological elements (temperature, precipitation totals, and days with precipitation) in each development period was used. The study showed that from the beginning of vegetative growth to the flowering stage, growth and development were most advanced in plants for which the average temperature was about 8–9 °C, and the number of days with precipitation was about 41. During generative growth, spike length is 80% determined by the precipitation total. Grain weight is 68% negatively determined by the temperature during dormancy (the higher the temperature during dormancy, the lower the weight of the kernel). A positive relationship was shown between yield and the precipitation total during the period from sowing to the onset of dormancy (r = 0.37). Winter wheat yield was 69% dependent on the density at harvest (the greater the density, the higher the final yield). On the basis of the 8-year results of the study, we conclude that the weather is highly variable from year to year, and therefore breeders should direct their research towards creating variants with much greater plasticity and high tolerance for unfavourable weather patterns.

In this work, an attempt was made to use the WOFOST (WOrld FOod Studies) model to simulate the potential and water-limited yield of early potato cultivars Lord and Denar. Data from cultivar experiments carried out at the Polish Research Centre for Cultivar Testing in 2004–2013 were used in the study. The Lord cultivar yielded 22.4–67.8 t fresh tuber weight per ha and 3.8–11.5 t ha⁻¹ dry tuber weight during the study period. The highest tuber yields (over 10 t ha⁻¹ dry weight) were obtained in 2009, 2011 and 2012, and the lowest in 2005 (3.8 t ha⁻¹) and 2006 (2.65 t ha⁻¹). The water-limited tuber yield simulated by WOFOST ranged from 3.6 to 10.9 t ha⁻¹ dry weight and was about 0.45 t ha⁻¹ higher on average than the actual yield. The planting period each year was between days 104 and 120 of the year, and harvesting took place between days 216 and 232. Water availability was a factor limiting the yield. The yield limited by water deficiency was 38.7% lower (irrespective of the cultivar) than the potential yield. The WOFOST model was sensitive to water deficiency, and the simulated (water-limited) yields were close to the actual yield or showed a clear downward trend indicating evident rainfall shortages in 2005 and 2006.

Summary: Wheat is one of the modern world’s staple food sources. Its production requires good environmental conditions, which are not always available. However, agricultural practices may mitigate the effects of unfavorable weather or poor-quality soils. The influence of environmental and crop management variables on yield can be evaluated only based on representative long-term data collected on farms through well-prepared surveys.The authors of this work analyzed variation in winter wheat yield among 3868 fields in western and eastern Poland for 12 years, as dependent on both soil/weather and crop management factors, using the classification and regression tree (CART) method. The most important crop management deficiencies which may cause low wheat yields are insufficient use of fungicides, phosphorus deficiency, non-optimal date of sowing, poor quality of seeds, failure to apply herbicides, lack of crop rotation, and use of cultivars of unknown origin not suitable for the region. Environmental variables of great importance for the obtaining of high yields include large farm size (10 ha or larger) and good-quality soils with stable pH. This study makes it possible to propose strategies supporting more effective winter wheat production based on the identification of characteristics that are crucial for wheat cultivation in a given region.