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Martin P.N. Gent and Richard J. McAvoy

an ebb and flow cycle in as short as 4 min. This short cycle restricts water uptake. From here on we refer to this short cycle irrigation process as the partial saturation ebb and flow watering (PSEFW). There are numerous benefits that could derive

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Martin P.N. Gent, Wade H. Elmer, Kranti Macherla, and Richard J. McAvoy

), developed an irrigation system for potted ornamental plants that can complete an ebb and flow cycle in 4 min. This short cycle restricts water uptake and achieves partial saturation of the root medium, which we refer to as partial-saturation ebb and flow

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James A. Poss, Christy T. Carter, Catherine M. Grieve, and Peter J. Shouse

Common stock flower production can be achieved under moderate levels of salinity and relatively low levels of nitrogen with no significant decrease in quality in a closed-recirculating irrigation system. A 4 × 4 factorial design with partial replication was used to assess the effects of salinity and nitrogen on the production of Matthiolaincana (L.). Seeds were sown in outdoor volumetric lysimeters at the George E. Brown, Jr., Salinity Laboratory in Riverside, Calif., with target electrical conductivity (EC) levels of 2, 5, 8, and 11 dS·m–1 combined with four nitrogen treatments of 35, 50, 75, and 100 ppm N. An empirical model was implemented to evaluate the growth response of each combination of salinity and nitrogen treatments over the course of plant development. The three-phase model is represented by an initial size parameter (alpha), an estimation of the intrinsic growth rate of the exponential phase (beta), a transitional phase between the first two phases (tl), the length of the linear phase (epsilon), and the final intrinsic saturation rate (gamma), The model successfully fitted the plant height data over time for all 16 nitrogen and salinity treatment combinations. Effects of salinity on epsilon and t2 (epsilon + t1) were nonsignificant. Nitrogen treatments had no significant effect on any of the model parameters and the effect of salinity was greatest when irrigation water EC was 11 dS·m–1. The length of the flower-bearing stems exceeded the standards recommended for commercial acceptability in all treatments (>41 cm). If 60 cm is the minimum length acceptable, then 50 ppm N or more where the EC was 8 dS·m–1 or less is required. Nitrogen uptake per unit evapotranspiration increased with salinity and nitrogen.

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Erin J. Yafuso and Paul R. Fisher

·L −1 at 1 atm and 25 °C. Within the root zone, Van Iersel and Dove (2014) pointed out that in a well-irrigated substrate, the relative humidity is likely to be close to 100%, resulting in reduced partial pressure of oxygen because of water vapor (19

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Roger Kjelgren, Lixue Wang, and Daryl Joyce

potentials through partial stomatal closure during drought to avoid cavitation ( West et al., 2007 ) but at the cost of reduced photosynthesis ( West et al., 2008 ). Isohydric species may be a more conservative and hence appropriate choice for low-water

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Erin J. Yafuso, Paul R. Fisher, Ana C. Bohórquez, and James E. Altland

and water as moisture level changes during crop production ( Caron and Nkongolo, 1999 ). Water potential of a substrate, and the relationship between VWC and plant available water, are usually measured as a substrate dries from saturation over time by

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Guifang Qi, Jean-Charles Michel, Pascal Boivin, and Sylvain Charpentier

approach ( Durner, 1994 ; Van Genuchten, 1980 ). The water retention expression thus assumes the following form: where υ is the water ratio (m 3 ·m −3 ); υ min and υ max are the minimal water ratio and the water ratio at saturation (m 3 ·m −3 ); ψ

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Kranti Macherla and Richard J. McAvoy

the duration of subirrigation to a short-cycle ( Gent and McAvoy, 2011 ), and thus, limit the degree of medium saturation. This method of watering has been referred to as short-cycle subirrigation management or partial-saturation irrigation ( Gent and

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Esmaeil Fallahi, Denise Neilsen, Gerry H. Neilsen, Bahar Fallahi, and Bahman Shafii

irrigated by one of these drip lines, and in the next cycle, they were irrigated by the other line. In this way, partial root-zone drying was created in the trees. The amount of water applied through this system was 65% of FD. Calculation of water

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Christopher Vincent, Diane Rowland, and Bruce Schaffer

after transplanting; Not primed: watered daily to saturation. Table 2. Priming treatment means of destructive harvest variables of ‘Red Lady’ papaya plants sampled at end of study (173 d after transplanting). Primed: maintained at −20 kPa for 3 weeks 1