Hydroponics is an increasingly important field for counterseason vegetable production because of its efficiency in fertilization, water, and space use. Furthermore, it can overcome the disadvantages of soil culture, such as continuous cropping
., 1988 ). Several studies evaluated the effect of fertilization regime (mainly regarding N) of stock plants on propagation rate. Henry et al. (1992) studied the Eastern Redcedar, Raymer et al. (2008) studied the Seacoast Marshelder, and Rowe et al
; Weibel et al., 2000 ; Zhao et al., 2007 ). The feasibility of container production of SHB cultivars, fertilized conventionally or organically, using a high tunnel requires investigation. Therefore, the objectives of this study were as follows: 1) to
6-m-long subplots separated by a 1.5-m alley. Production systems (LT and open field) were allocated randomly to each subplot. Soil test and fertilization. Four soil samples (one from each block) were collected from the top 15 cm before fertilizer
Methods for Zn fertilization of `Hass' avocado (Persea americana Mill.) trees were evaluated in a 2-year field experiment on a commercial orchard located on a calcareous soil (pH 7.8) in Ventura County, Calif. The fertilization methods included soil- or irrigation-applied ZnSO4; irrigation-applied Zn chelate (Zn-EDTA); trunk injection of Zn(NO3)2, and foliar applications of ZnSO4, ZnO, or Zn metalosate. Other experiments evaluated the influence of various surfactants on the Zn contents of leaves treated with foliar-applied materials and on the retention and translocation of radiolabeled 65ZnSO4 and 65Zn metalosate after application to the leaf surface. In the field experiment, tree responses to fertilization with soil-applied materials were affected significantly by their initial status, such that only trees having <50 μg·g–1 had significant increases in foliar Zn contents after fertilization. Among the three soil and irrigation treatments, ZnSO4 applied at 3.2 kg ZnSO4 per tree either as a quarterly irrigation or annually as a soil application was the most effective and increased leaf tissue Zn concentrations to 75 and 90 μg·g–1, respectively. Foliar-applied ZnSO4, ZnO, and Zn metalosate with Zn at 5.4, 0.8, and 0.9 g·liter–1, respectively, also resulted in increased leaf Zn concentrations. However, experiments with 65Zn applied to leaves of greenhouse seedlings showed that <1% of Zn applied as ZnSO4 or Zn metalosate was actually taken up by the leaf tissue and that there was little translocation of Zn into leaf parenchyma tissue adjacent to the application spots or into the leaves above or below the treated leaves. Given these problems with foliar Zn, fertilization using soil- or irrigation-applied ZnSO4 may provide the most reliable method for correction of Zn deficiency in avocado on calcareous soils.
., 1975 ), whereas other authors label it as only partially SI, not expressing complete rejection of self-pollen but preferring cross-pollen for fertilization and hence increasing fruit set and yield under cross pollination ( Dimassi et al., 1999 ; Lavee
Leaf concentrations of N, P, K, Fe, and Mn in `Sterling' muscadine grapes (Vitis rotundifolia Michaux) grown for 2 years in sand culture were not influenced by different N fertilizer sources. Leaf Zn and Cu were higher in plants receiving N as NH4NO3 rather than as (NH4)2SO4. Growth was greatest in plants fertilized with NH4NO3 compared to those with either (NH4)2SO4 or NaNO3 fertilization. Leaf Ca, Mg, Mn, and Cu content decreased linearly and leaf N increased linearly as N fertilizer rates were raised from 1.8 to 16.1 mM. Plant growth was a positively correlated with leaf N but was negatively correlated with leaf Ca, Mg, and Mn content. Percent Mg in the leaves was reduced when N levels, regardless of N source, were raised from the low (1.8 mM) to middle (5.4 mM) rate. High leaf N levels were correlated with lower Ca and Mg in the leaves, indicating a possible relationship between N fertilization and the late-season Mg deficiency often observed in muscadine grapes.
improve sustainability and profitability. Three of those challenges are: 1) accessing premium cultivars with enhanced fruit quality and human nutritional properties; 2) determining appropriate fertilization practices to reduce nutrient leaching to
. The few N fertilizer recommendations for vines and groundcovers reported in the literature are often very general and variable. For example, Park-Brown and Knox (2010) noted that most vine species can benefit from N fertilization during establishment
et al., 2011b ). Supplemental nutrition through fertilization is essential in these soilless media nursery systems ( Landis et al., 1989 ). When not optimized for a given species and cultural conditions, however, fertilization can result in