The experiment was carried out to determine the effects of different irrigation water levels on yield and some quality parameters of lettuce (Lactuca sativa L. Var. Longifolia cv.) under greenhouse conditions. Irrigation water was applied through drip irrigation method with 7 days interval during the total growing season. Irrigation treatments consisted of six different water levels (I1: non-irrigation, I2: 25 %, I3: 50 %, I4: 75 %, I5: 100 % and I6: 125 % of cumulative evaporation measured from Class A pan). The amount of irrigation water ranged between 0 and 106.3 mm among the treatments. Evapotranspiration (ET) values varied from 69.1 to 158.5 mm for the treatments. The highest yield was obtained from the I5 followed by I4. A significant polynomial relation (R2=0.77) was obtained between the yield and irrigation water, and linear relation (R2=0.99) was obtained between the yield and ET. This indicated that when irrigation water increased, yield also increased to a certain point. However, when the amount of irrigation water exceeded the plant water requirement, lettuce yield decreased. Yield response factor (Ky) was determined as 1.97. Since Ky ˃ 1, lettuce was very sensitive to water deficiency. In addition, the highest water use efficiency (WUE) and ...
The effect of deficit irrigation imposed in July-August period on shoot growth and flower formation in container grown rhododendron in commercial nursery were assessed. Plants were exposed to three irrigation regimes based on potential evapotranspiration rates (100% ET0 - well-watered control plants, 75% ET0 - moderate drought and 50% ET0 - severe drought). The values of evapotranspiration were calculated using the Penman-Monteith model. The degree of drought had significant effect on the plant growth and water status of plants. Severe drought inhibited secondary shoot elongation compared to less stressful regime but did not affect flower formation. ‘Catawbiense Boursault', ‘Nova Zembla' and ‘Pearce's American Beauty' plants exposed to severe drought were shorter, respectively by 39, 45 and 86% than well-irrigated plants and two of the three cultivars ‘Catawbiense Boursault' and ‘Pearce's American Beauty' produced fewer secondary branches (5.9 and 0.3) compared to control plants (9.2 and 1.7, respectively). Moderate drought did not affect plant growth but resulted in flower bud formation in ‘Nova Zembla' and ‘Pearce's American Beauty's cultivars. Estimated water consumption by rhododendrons throughout the whole growing season was reduced by 15% for moderate and 25% for severe drought compared to control, well-watered plants. The results have significant implications ...
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). ...
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 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 aim of the study was to compare the water requirements and the precipitation deficiencies during cultivation of asparagus in the period from June to August in the regions of Bydgoszcz and Wroclaw. The water needs were calculated using the plant coefficient. The reference evapotranspiration was measured by Grabarczyk's method (1976). The coefficients kc, determined for the Polish conditions by Rolbiecki (2013), were used to estimate the water requirements considered as the crop evapotranspiration. In the studied period (from June to August, 1996-2015), higher water requirements of asparagus were noted in the Wroclaw region (366.1 mm) than in the Bydgoszcz region (288.5 mm). The monthly water needs in June, July and August were 69.8 mm, 128.8 mm and 167.5 mm, respectively, in the Wroclaw region, and 55.5 mm, 98.5 mm and 134.5 mm, respectively, in the Bydgoszcz region. In July, the tendency to increase the water requirements in both observed regions was noted. The monthly crop evapotranspiration in July rose in each decade by 12.3 mm in the Bydgoszcz region and by 21.2 mm in the Wroclaw region. In the 20-year study, the rainfall deficit in June and July during 11-13 years was noted. In August, the precipitation deficiencies were ...
