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Yields and Bioactive Substances of Selected European Asparagus Cultivars Grown for Green Spear Production as Influenced by of Post-Harvest Drip Irrigation on Sandy Soil in Central Poland
Water Needs of Willow (Salix L.) in Western Poland
Willows are one of the plants which can be used to produce biomass for energy purposes. Biomass production is classified as a renewable energy source. Increasing the share of renewable sources is one of the priority actions for European Union countries due to the need to reduce greenhouse gas emissions. To achieve the best possible growth of the willow and increase its biomass for fuel, it is crucial to provide optimal water conditions for its growth. The aim of the study was to determine the water requirements of willows under the conditions of the western Polish climate and to verify whether this area is potentially favourable for willow cultivation. The novelty of this paper lies in its multi-year climatic analysis in the context of willow water needs for the area of three voivodships: Lubusz, Lower Silesian, and West Pomeranian. This is one of the few willow water-needs analyses for this region which considers the potential for widespread willow cultivation and biomass production in western Poland. Reference evapotranspiration (ETo) was determined by the Blaney-Criddle equation and then, using plant coefficients, water needs for willow were determined. Calculations were carried out for the growing season lasting from 21 May to 31 October. The estimated water needs during the vegetation season amounted on average to 408 mm for the West Pomeranian Voivodeship, 405 mm for the Lubusz Voivodeship, and 402 mm for the Lower Silesian Voivodeship. The conducted analysis of variance (ANOVA) showed that these needs do not differ significantly between the voivodeships. Therefore, it can be concluded that the water requirements of willows in western Poland do not differ significantly, and the whole region shows similar water conditions for willow cultivation. Furthermore, it was found that water needs are increasing from decade to decade, making rational water management necessary. This is particularly important in countries with limited water resources, such as Poland. Correctly determining the water requirements of willow and applying them to the cultivation of this plant should increase the biomass obtained. With appropriate management, willow cultivation in Poland can provide an alternative energy source to coal.
The effects of high temperature and low humidity on crop water stress index of seed pumpkin plants (Cucurbita pepo L.) in semi-arid climate conditions
This study aimed to evaluate the effects of high temperature and low humidity on the crop water stress index (CWSI) of seed pumpkin plants grown under semi-arid climate conditions to determine the optimum irrigation time. This research unveils the critical impact of high temperature and low humidity on seed pumpkin growth, emphasizing the vital role of the CWSI in optimizing irrigation strategies and seed yield. Moreover, the relationship between CWSI, physiological parameters, and seed yield of the pumpkin was investigated. The mean CWSI values in the I70 (0.40) and I35 (0.56) treatments were 42% and 100% higher, respectively than those in the full irrigation (I100) treatment (0.28). While the I70 treatment showed manageable water stress with minimal impact, the I35 treatment experienced severe stress, significantly reducing crop growth and yield. The mean seed yield (SY) in the I70 treatment increased to 1245.2 kg ha–1 compared to I35 (903.3 kg ha–1) but remained lower than I100 (1339.3 kg ha–1). The CWSI had negative correlations (p ≤ 0.01) with seed yield, chlorophyll content, and leaf area index, while it had positive correlations with water use efficiency and irrigation water use efficiency (p ≤ 0.01). This study showed that pumpkins could be grown successfully at 30% water deficit conditions, and a water deficit higher than 30% may cause a significant seed yield loss in semi-arid climate conditions. In addition, the results highlight the importance of optimal irrigation and CWSI monitoring for informed irrigation decisions and sustainable agricultural practices. Therefore, moderate water deficit (I70) can be adopted in pumpkin cultivation as an alternative to full irrigation.
Derinkuyu dry bean irrigation planning in semi-arid climate by utilising crop water stress index values
This study was conducted to determine crop water stress index (CWSI) values and irrigation timing in the case of Derinkuyu dry bean ( Phaseolus vulgaris L.). In 2017, dry beans were grown as the main crop according to the field design consisting of plots divided into randomised blocks. Irrigation treatment comprised full irrigation (I100) and irrigation issues with three different levels of water stress (I66, I33, I0). This study applied 602 mm of water under the I100 irrigation. The yield of Derinkuyu dry beans was equal to 3576.6 kg∙ha –1 in I100 irrigation. The lower limit (LL) value, which is not necessary for the determination of CWSI, was obtained as the canopy–air temperature difference ( Tc – Ta) versus the air vapour pressure deficit ( VPD). The upper limit (UL) value, at which the dry beans were wholly exposed to water stress, was obtained at a constant temperature. The threshold CWSI value at which the grain yield of dry beans started to decrease was determined as 0.33 from the measurements made with an infrared thermometer before irrigation in I66 irrigation treatment. As a result, it can be suggested that irrigation should be applied when the CWSI value is 0.33 in dry beans. Furthermore, the correlation analysis revealed a negative correlation between grain yield and crop water stress index and a positive correlation between yield and chlorophyll content. According to variance analysis, significant relationships were found between the analysed parameters at p ≤ 0.01 and p ≤ 0.05.
Evaluation of Crop Water Stress Index (CWSI) for High Tunnel Greenhouse Tomatoes under Different Irrigation Levels
An experiment was conducted to determine the effect of water stress on yield and various physiological parameters, including the crop water stress index for tomatoes in the Central Anatolian region of Turkey. For this purpose, the irrigation schedule used in this study includes 120%, 100%, 80%, and 60% (I120, I100, I80, I60) of evaporation from the gravimetrically. Water deficit was found to cause a stress effect in tomato plants, which was reflected in changes in plants’ morphological and pomological function (such as stem diameter, fruit weight, pH, titratable acidity, and total soluble solids). Irrigation levels had a significant effect on the total yield of tomatoes. The lowest water use efficiency (WUE) was obtained from the I60, while the highest WUE was found in the I100 irrigation level. The CWSI was calculated using an empirical approach from measurements of infrared canopy temperatures, ambient air temperatures, and vapor pressure deficit values for four irrigation levels. The crop water stress index (CWSI) values ranged from −0.63 to a maximum value of 0.53 in I120, from −0.27 to 0.63 in I100, from 0.06 to 0.80 in I80, and from 0.37 to 0.97 in I60. There was a significant relation between yield and CWSI. The yield was correlated with mean CWSI values, and the linear equation Total yield = −2398.9CWSI + 1240.4 can be used for yield prediction. The results revealed that the CWSI value was useful for evaluating crop water stress in tomatoes and predicting yield.
Water Needs of Sweet Cherry Trees in the Light of Predicted Climate Warming in the Bydgoszcz Region, Poland
The Bydgoszcz region (Poland) is located in an area with a very high demand for supplementary irrigation during the vegetation period of plants. The projected global warming will bring a rise in the water needs of crops, and thus a further increase in irrigation needs. The goal of the study was an attempt to estimate the water needs of sweet cherry trees in 2021–2050 (forecast period) in the region of Bydgoszcz. The years 1981–2010 were adopted as the reference period. The water needs of sweet cherry trees were calculated on the basis of air temperature using the Treder method, in which water needs are equated with the potential evapotranspiration of a given fruit tree species. It was found that in the growing season of the forecast period, the relative diversity of sweet cherries’ water needs was relatively small (7%). The highest variability of monthly water needs was in April, May, and June. The seasonal water needs amounted to 573 mm, with very high monthly water needs noted in July (139 mm) and August (134 mm). A significant trend of the time variability of water needs was calculated only in August. During this month, it is predicted that the water needs will rise by 5 mm in each subsequent decade. These results will be helpful in the design of sweet cherry irrigation treatments.