The suitability of capacitance probes for measuring the actual variations in substrate water content in container-grown ornamental species (Lawson cypress) was examined. The probes were installed in the plant containers. Weighing measurement data on water loss was used to assess the actual changes in substrate water content (plant water use). In an additional test, an evaluation of temperature sensitivity of the capacitance probe was performed under laboratory conditions. The probe was placed in a container containing the growing medium (peat substrate) with a defined (stable) moisture content. The substrate temperature was modified and the changes in probe output were recorded. The experiment demonstrated the existence of the effect of temperature on the quality of soil moisture measurements conducted with the capacitance method. The accuracy of the results obtained from measurements with dielectric sensors in relation to the data obtained by means of weighing platforms depended largely on the temperature profile of the measured medium. It was demonstrated that temperature variations explained 99% of the observed differences in the results of moisture content measured with the capacitance method. Due to the fact that there is no possibility of developing universal factors (for different sensors and substrates) for correcting the influence of ...
In temperate zone, early freeze, particularly if preceded by a period of warm and wet weather, can severely injure many woody plants. The young plants are particularly sensitive to frost, especially those grown in containers. The timing and capacity of cold acclimation are modified by environmental cues. We examined whether regulated deficit irrigation (RDI) imposed in the fall affects cold acclimation of containerized Lawson cypress (Chamaecyparis lawsoniana)‘Columnaris' and Knaphill-Exbury azalea (Rhododendron) ‘Oxydol'. Three-year-old plants were grown in containers placed in the open field and were cultivated according to standard nursery practice. In the end of growing season (from 5th October to 2nd November 2015, half of the plants were expose to moderated water stress by ceasing irrigation and protecting them from the rain (RDI treatment). The volumetric water content of the growing medium gradually decreases in this time from 0.45 to 0.2 m3/m3. Irrigation of the second part of the plants were continued in October and water content was maintained at 0.45 m3/m3 (control treatment). Cold hardiness of stem tissues was assessed two times (2nd November and 7th December) in the laboratory using the ion-leakage test. Stem tissue were exposed to 6 test temperatures, ranging from +4 to -26˚C. Additionally, ...
This paper presents data on daily precipitation totals from six meteorological stations and the climatic water balance for the stations located throughout Poland in 2011-2015. The following sequences of days without precipitation were distinguished: from 11 to 15 days, from 16 to 20 days, and of more than 20 days. The number of precipitation-free sequences during the growing season in 2011-2015 was highly variable. Over the studied period, there were from 1.0 rainless sequence in Wtelno to 2.4 such sequences in Gołębiów per one growing season. The most frequently occurring were sequences of 11-15 days, while those of 16-20 days were less frequent. In the years under analysis, all of the different sequences occurred most frequently in July, and the least frequently in April. The highest numbers of sequences without precipitation were recorded in the south-east of Poland (Zakalniki, Gołębiów). ...
The purpose of that article was to show the significance of water as the source of plant pathogens, and need of it effective disinfection methods in modern agriculture and horticulture. The increase in the cost of agricultural water use for crop irrigation and the necessity of using the same water several times, as well as the changing climatic conditions, including prolonged shortage of atmospheric precipitation and often extreme temperatures during the summer, necessitate the selection of an effective, easy to apply and economical method of disinfecting recirculated water to eliminate or minimize the occurrence of the most serious plant pathogens inhabiting various water sources. Among them, microorganisms of the genera Phytophthora, Pythium and Fusarium, and the species Rhizoctonia solani, Verticillium dahliae and some pathogenic bacteria pose the most serious threat. Some of them can be found in rivers, streams, ponds and water reservoirs, others are soil-borne pathogens that cause root and stem base rot of many plant species. The available literature describes at least a dozen methods of water disinfection, among them slow filtration through sand or lava filters, chlorination and heating. The literature data indicates that the use of sand filters is the most effective, safe and cheapest ...
The effects of bacterial and fungal inocula on the growth, yielding, and nutritional status of apple trees was evaluated in 3-years experiment (2018 - 2020). The experiment included the following treatments: (i) control (unfertilized soil), (ii) no fertilization + soil application of fungi, (iii) no fertilization + soil application of bacteria. The mixture of beneficial fungi contained two species: Aspergillus niger and Purpureocillium lilacinum. The mixture of beneficial bacteria contained three strains of Bacillus (Bacillus sp., Bacillus amyloliquefaciens and Paenibacillus polymyxa). The application of beneficial microorganisms (especially bacterial strains) to the soil (without additional mineral fertilization) enhanced the growth of the apple trees. In the third year of the study (2020), the trees grown in the plots inoculated with bacteria bloomed the most intensively. Plant nutritional status (expressed as concentrations of elements in leaves) was not affected by the application of the bacterial strains or filamentous fungi. The stronger growth of trees in the plots where the bacteria were used was likely related not so much to the nutritional status of the trees, but to the mitigation of the influence of the negative factors that cause the replant disease. ...
