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 ...
The response of three raspberry cultivars (‘Beskid', ‘Laszka', ‘Latham') to water deficiency was examined by evaluating selected physiological parameters. Plants were subjected to two different water regimes: optimal irrigation (control), and reduced irrigation. Leaf water potential in all cultivars was decreased as a result of limited water availability. Genotypes differed in their response to water deficiency. Under water shortage conditions, the rate of CO2 assimilation was the highest in ‘Latham' and ‘Laszka'. On the other hand, the severe inhibition of photosynthesis was observed in ‘Beskid'. Taking all data into consideration it was concluded that cultivar ‘Latham' and ‘Laszka' appeared to be more drought resistant which was reflected by enhanced physiological parameters. ...
The aim of the study was to estimate water requirements of strawberry nursery grown under protected conditions. Strawberry mother plants were cultivated in pots filled with a mixture of peat and coconut substrate. The plants were irrigated by a drip system. Watering frequency was controlled by a developed prototypical weight-based irrigation scheduling system. This system enabled automatic control of irrigation depending on actual plant water requirements. The results showed usefulness of the developed system for scheduling the irrigation of strawberry. The obtained data on irrigation frequency and water application rates provided information on actual evapotranspiration of strawberry nursery (ETr). Reference evapotranspiration (ETo) was calculated using Grabarczyk equation on a basis of temperature and air humidity data. Having both ETo and ETr values made it possible to calculate crop coefficient (Kc) for strawberry nursery. Kc varied from 0.05 in February (just after planting the mother plants) to 0.62 at the end of cultivation period (before harvesting the plantlets). ...
The increasing role of perennials in ornamental nurseries requires the elaboration of efficient and accurate irrigation control of this specific group of plants. The experiment was conducted in 2015 in Research Institute of Horticulture, in Skierniewice. The aim of the study was to determine the water requirements and designate the specific evapotranspiration crop coefficient Kc of several perennials, commonly grown in Polish ornamental nurseries. Water requirements of perennials were evaluated using weighing lysimeters. At the same time the recorded climate parameters allowed to calculate the potential evapotranspiration (ET0). Lysimeter measurements and meteorological data allowed determine specific to each species crop coefficient (Kc). The Kc values were determined by dividing ETc by ET0. The obtained results showed that irrespectively of plant growth phase there is strong correlation between climate parameters and real crop evapotranspiration (ETc) of six evaluated perennials: Anemone hupehensis 'Prinz Heinrich', Echinacea purpurea ‘Guava Ice', Hemerocallis, ‘Sandra Elisabeth', Salvia nemorosa ‘Mainacht' and Veronica spicata ‘Royal Candles Glory'. The Kc coefficients of all species were changed during the growth season and increased according to plant development and percentage of ground coverage of soil in the lysimeter by leaves. The strong, positive correlation was shown for daily and hourly ...
The experiment was conducted to evaluate the effect of different irrgation managements during poinsettia cultivation. The existing systems of calculationg evaporative demand and thus irrigation frequency are usually based on growing media moisture sensors or climatic sensors (temperature, relative humidity and solar radiation). Poinsettia ‘Primero Red' was grown in pots (1,2 dm3) in greenhouse and irrigated using drippers, according to three different levels: I - irrigation at 40% ±2, (v/v) of water content in growing medium, II - automatically controlled irrigation according to continuous readings of plant weight (all plants placed on special balance connected with irrigation controller) III - irrigation at 72% ±2, (v/v) of water content. The water content in growng media in each treatments was controlled using capacitance probes ECH2O-10 (Decagon Devices, USA). The obtained results showed that irrigation control system based on continuous readings of specially designed balance connected to the computer gave very good results in poinsettia cultivation. Plant in this treatment had the best plant shape and the highest bract area. Moderate water deficit (irrigation at 40% of water content in growing medium) resulted in significant reduction in transpiration and stomatal conductance and thus reduced plant growth and quality. ...
The aim of the study (2011-2013) was assessment of growth and yielding of apple trees (‘BeniShogun'/M.9) grown in replanted orchard. Undersowing the trees with white mustard and irrigation (performed on the basis of soil moisture measurements) were the experimental factors. Irrigation significantly affected plant growth, whereas no positive effect of white mustard application on performance of apple tree was observed. The trees started to yield in the third year after planting and yielding was different in the subsequent years of the study. A positive influence of irrigation on yield and fruit quality was observed. Undersowing the trees with white mustard reduced fruit yield and worsened its quality. It was especially visible on the non-irrigated plots. The results confirmed high effectiveness of irrigation of apple trees grown in replanted apple orchards ...
Poland has one of the smallest fresh water resources in Europe. Due to variability of Polish climate, irrigation became an indispensable element of intensive horticultural production. Recent study has shown that Polish farmers do not use any criteria to estimate plant water requirements for controlling irrigation, which leads to waste of water and energy. This is because userfriendly technologies enabling rational use of water resources are not easily available. The objective of the project is to develop an effective system for control of irrigation in ornamental nurseries, based on measurements of plant parameters, soil conditions and climatic data. To realize this approache the crop coefficient (k) for several important nursery species should be determined. Also the method of restricted irrigation (Regulated Deficit Irrigation - RDI) to control plant shape and plant quality will be tested on several important nursery cultivars. Additionally quantitative and qualitative evaluation of drainage water originated from container ornamental nurseries will be performed. The technology developed within the project will become the key element of the strategy of rational plant irrigation in ornamental nurseries. This is novel, hitherto not implemented approach to the problem of rational irrigation water use in plant production ...
