water applied for watermelon grown using a smartphone vegetable irrigation–scheduling application (VegApp), water balance (WB), and soil moisture sensor (SMS) methods at Tifton, GA, in 2016 and 2017. In 2017, the VegApp accounted more appropriately for
Luke Miller, George Vellidis, and Timothy Coolong
Luke Miller, George Vellidis, Osama Mohawesh, and Timothy Coolong
volume and daily water use for tomato irrigated using smartphone vegetable irrigation scheduling application (VegApp), water balance (WB), and soil moisture sensor (SMS) methods at Tifton, GA in 2016 and 2017. Table 3. Average mo.ly soil water tension at
Jong Suk Lee and Young A. Kim
Rose (Rosa hybrida) cvs. Red Velvet, First Red, Sonia, and Saphir stems harvested at bud stage were kept in deionized water or preservative solution (3% sucrose + 200 ppm HQS + 0.1 mM ethionine) at 21°C under continuous light (1200 lux). Vase life of `First Red' and `Saphir' was much longer than those of `Red Velvet' and `Sonia' held in deionized water. Severe bent-neck was observed in `Red Velvet' flowers held in deionized water in 8 days after harvest. Rose flowers held in preservative solution resulted in extended vase life and inhibited senescence and bent-neck in four cultivars. Neck strength of `First Red' and `Saphir' rose flowers having no bent-neck and long vase life was stronger than `Red Velvet' and `Sonia' having frequent bent-neck and short vase life. Neck strength was also increased by preservative solution. Faster changes of water balance to minus value were detected in the rose flowers held in deionized water than those held in preservative solution. `Red Velvet' flowers having much absorption of water but more transpiration caused a fast change to a minus value in water balance and early bent-neck. Cell sap pH gradually increased in petal and stem of rose cultivars during senescence. Cell sap pH of flowers held in distilled water were higher than those held in preservative solution. Increased cell sap pH of rose flowers caused rapid change to blueing and yellowing of petals.
Alberto Pardossi and Luca Incrocci
ensure that all irrigation water is used by the crop. A schedule to maximize net economic return, which depends also on water price, is less common. Conventional methods for IS rely on determination of soil water balance (weather-based method) or on the
Hongyan Sun, Kelly Kopp, and Roger Kjelgren
, and woody plants. Once established, minimum water-efficient landscape water needs under water-limiting conditions may then be more clearly defined. Objectives of this study were to develop water balances for water-efficient landscapes with no soil
Soo-Hyung Kim, Kenneth A. Shackel, and J. Heinrich Lieth
Shoot-bending has become a standard cultural practice in cut-flower rose (Rosa hybrida L.) production. Physiological effects of shoot-bending on leaf net photosynthesis (A), stomatal conductance (gs), transpiration rate (E), and stem water potential (ψ) were investigated for rose plants. With saturating light conditions, shoot-bending decreased rates of A, gs, and E in comparison with the rates prior to shoot-bending. A, gs, and E of bent shoots were significantly lower than those of the control shoots that were not bent. The differences in A between bent and control shoots decreased over time, disappearing within 3 weeks after bending. Bent shoots exhibited reduced ψ. Leaves projecting upward on a bent stem were found to have higher A, gs, and E than those projecting downward. This was probably due to the destruction of xylem vessels serving the leaves attached to the lower side (compression side) of the bent stem. Our results support the hypothesis that hydraulic conductivity is reduced in bent shoots probably due to disturbed xylem tissues, and that reduced photosynthetic rates of bent shoots are a function of water status.
Eric Simonne, Nadia Ouakrim, and Arnold Caylor
Potato (Solanum tuberosum L.) is often produced as a nonirrigated crop in the southeastern United States. This practice makes tuber yields dependent on rainfall pattern and amount. An irrigation scheduling method based on a water balance and daily class A pan evaporation (Ep) was evaluated during 1996 and 1998 on a Hartsells fine sandy loam soil for `Red LaSoda' potatoes. Planting dates were 9 and 7 Apr. in 1996 and 1998, respectively, and standard production practices were followed each year. The model tested was (13 DAH + 191) * 0.5 ASW = D DAH-1 + [Ep * (0.12 + 0.023 DAH - 0.00019 DAH2) - RDAH - IDAH], where DAH was days after hilling, ASW was available soil water (0.13 mm/mm), D was soil water deficit (mm), R was rainfall (mm), and I was irrigation (mm). Controlled levels of water application ranging between 0% and 200% of the model rate were created with drip tapes. Four and seven irrigations were scheduled in 1996 and 1998, respectively. For both years, no interaction between irrigation regime and nitrogen rate was observed. Irrigation rate significantly influenced total yield and marketable yield (R 2 > 0.88, P < 0.01). Highest total yields occurred at 99% and 86% of the model rate in 1996 and 1998, respectively. These results show that supplementing rainfall with irrigation and controlling the amount of water applied by adjusting irrigation to actual weather conditions increased potato marketable yield. Over the 2-year period of the study, an average additional profit of $563/ha/year was calculated from costs and returns due to irrigation, suggesting that drip-irrigation may be economical for potato production.
G.A. Picchioni, Wayne A. Mackay, and Mario Valenzuela-Vázquez
, each the average of eight individual racemes. Raceme water balance, fresh weight, and dry weight. Postharvest solution uptake and transpiration per eight racemes declined linearly from 2 d to 6 d of vase life ( Table 1 and Fig. 3
Lingfang Kong, Fan Li, Ronghui Du, Huaiting Geng, Shifeng Li, and Jihua Wang
postharvest quality and vase life of cut flowers mainly depend on the water balance and carbohydrate consumption of petals ( Arrom and Munné-Bosch, 2012 ; Bahremand et al., 2014 ; Fanourakis et al., 2012 ; van Doorn, 2012 ). The water balance is mostly
Dalong Zhang, Yuping Liu, Yang Li, Lijie Qin, Jun Li, and Fei Xu
is to be maintained, J must equal E , and then ∆ W = 0. Water balance is therefore of fundamental importance to maintain a physiologically favorable water content and to avoid desiccation. Disruptions in the water balance and plant water stress