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Belleville, MI, United States

Fisher P.R.,University of Florida | Argo W.R.,Blackmore Company | Biernbaum J.A.,Michigan State University

Additional index words. basicity, growing media, impatiens, limestone, nitrogen CCE, peat, petunia, pelargonium, pH management, soilless media, water-soluble fertilizer Abstract. Two experiments were run to validate a "Nitrogen Calcium Carbonate Equivalence (CCE)" model that predicts potential fertilizer basicity or acidity based on nitrogen (N) form and concentration for floriculture crops grown with water-soluble fertilizer in containers with minimal leaching. In one experiment, nine bedding plant species were grown for 28 days in a peat-based substrate using one of three nutrient solutions (FS) composed of three commercially available water-soluble fertilizers that varied in ammonium to nitrate (NH4 +:NO3 -) ratio (40:60, 25:75, or 4:96) mixed with well water with 130 mg·L-1 calcium carbonate (CaCO3) alkalinity. Both the ammoniumnitrogen (NH4-N) content of the FS and plant species affected substrate pH. Predicted acidity or basicity of the FS for Impatiens walleriana Hook.f. (impatiens), Petunia 3hybrida E. Vilm. (petunia), and Pelargonium hortorum L.H. Bailey (pelargonium) from the Nitrogen CCE model was similar to observed pH change with an adjusted R2 of 0.849. In a second experiment, water alkalinity (0 or 135.5 mg·L-1 CaCO3), NH4 +:NO3 - ratio (75:25 or 3:97), and N concentration (50, 100, or 200 mg·LL1 N) in the FS were varied with impatiens. As predicted by the N CCE model, substrate pH decreased as NH4 + concentration increased and alkalinity decreased with an adjusted R2 of 0.763. Results provide confidence in the N CCE model as a tool for fertilizer selection to maintain stable substrate pH over time. The limited scope of these experiments emphasizes the need for more research on plant species effects on substrate pH and interactions with other factors such as residual limestone and substrate components to predict pH dynamics of containerized plants over time. Source

Huang J.,University of Florida | Fisher P.R.,University of Florida | Horner W.E.,University of Florida | Argo W.R.,Blackmore Company
Journal of Plant Nutrition

The objective was to quantify how the concentration and particle size of unreacted "residual" limestone affected pH buffering capacity for ten commercial and nine research container substrates that varied in residual calcium carbonate equivalents (CCE) from 0.3 to 4.9 g CCE·L-1. The nine research substrates contained 70% peat:30% perlite (by volume) with dolomitic hydrated lime at 2.1 g·L-1, followed by incorporation of one of four particle size fractions [850 to 2000 μm (10 to 20 US mesh), 250 to 850 μm (20 to 60 US mesh), 150 to 250 μm (60 to 100 US mesh), or 75 to 150 μm (100 to 200 US mesh)] of a dolomitic carbonate limestone at 0, 1.5 or 3.0 g·L-1. Substrate-pH buffering was quantified by measuring the pH change following either (a) mineral acid drenches without plants, or (b) a greenhouse experiment where an ammonium-based (acidic) or nitrate-based (basic) fertilizer was applied to Impatiens wallerana Hook. F. Increasing residual CCE in commercial substrates was correlated with greater pH buffering following either the hydrochloric acid (HCl) drench or impatiens growth with an ammonium-based fertilizer. Research substrates with high applied lime rate (3.0 kg·m-3) had greater pH buffering than at 0 or 1.5 g·L-1. At 3 g·L-1, the intermediate limestone particle size fractions of 250 to 850 μm and 150 to 250 (20 to 60 or 60 to 100 US mesh) provided the greatest pH-buffering with impatiens. Particle fractions finer than 150 μm reacted quickly over time, whereas buffering by particles coarser than 850 μm was limited because of the excessively slow reaction rate during the experimental periods. Addition of acid from either an ammonium-based fertilizer or HCl reduced residual CCE over time. Dosage with 40 meq acid from HCl per liter of substrate or titration with HCl acid to substrate-pH of 4.5 were well-correlated with pH buffering in the greenhouse trials and may be useful laboratory protocols to compare pH buffering of substrates. With nitrate fertilizer application, residual CCE did not affect buffering against increasing pH. Residual limestone is an important substrate property that should be considered for pH management in greenhouse crop production under acidic conditions. © Taylor & Francis Group, LLC. Source

Santos K.M.,University of Florida | Fisher P.R.,University of Florida | Yeager T.,University of Florida | Simonne E.H.,University of Florida | And 2 more authors.

The objective was to quantify the effect of the timing of macronutrient applications on nutrient uptake, growth, and development of Petunia ×hybrida Hort. Vilm. -Andr. 'Supertunia Royal Velvet' during vegetative propagation. Starting with unrooted cuttings (Day 0), fertigation was applied continuously at three time intervals (Day 0 to 7, Day 8 to 14, or Day 15 to 21) using either a "complete" (C) water-soluble fertilizer containing (inmg.L -1) 75 NO 3--N, 25 NH 4-N, 12 phosphorus (P), 83 potassium (K), 20 calcium (Ca), 10 magnesium (Mg), 1.4 sulfur (S), 2 iron (Fe), 1 manganese (Mn), 1 zinc (Zn), 0.5 copper (Cu), 0.5 boron (B), and 0.2 molybdenum(Mo) or a micronutrient fertilizer (M) containing (inmg.L -1) 1.4 S, 2 Fe, 1 Mn, 1 Zn, 0.5 Cu, 0.5 B, and 0.2 Mo in a complete factorial arrangement. With constant fertigation using the C fertilizer, plant dry weight (DW) doubled from Day 0 (sticking of unrooted cuttings) to Day 7 (0.020 g to 0.047 g), root emergence was observed by Day 4, and by Day 7, the average length of primary roots was 2.6 cm. During any week that the M fertilizer was substituted for the C fertilizer, tissue N-P-K concentrations decreased compared with plants receiving the C fertilizer. For example, plants receiving the M fertilizer between Day 0 and 7 had 20% lower tissue-N concentration at Day 7 compared with those receiving the C fertilizer. Although both shoot DW and leaf count increased once macronutrient fertilization was resumed after Day 7, final shoot DW and leaf count were lower than plants receiving C fertilizer from Day 0 to 21. Time to first root emergence was unaffected by fertigation. Constant application ofCresulted in a higher shoot-to-root ratio at Day 21 than all other treatments. Results emphasize the importance of early fertigation on petunia, a fast-rooting species, tomaintain tissue nutrient levelswithin recommended ranges. Source

Blackmore Co. | Date: 2012-11-05

Containers, not of metal for commercial or industrial use; packaging containers of plastic material; containers of plastic material for commercial or industrial use for seeding, growing, transplanting and propagating plants, seedlings and horticultural specimens; containers, not of metal for use in commercial or industrial horticulture applications. Trays for horticulture, namely, plant cultivation trays; plant and seedling growing trays; plant growing pots; plant growing trays; propagation trays for plants, seeds and seedlings.

Johnson C.N.,University of Florida | Fisher P.R.,University of Florida | Huang J.,University of Florida | Yeager T.H.,University of Florida | And 4 more authors.
Scientia Horticulturae

The potential of a water soluble fertilizer (WSF) to raise or lower substrate-pH is estimated in calcium carbonate equivalents (CCE) of acidity or basicity per unit mass of fertilizer. The CCE is currently estimated using Pierre's Method, PM, which is based on assumptions as to the effects of nitrogen and other ions in field soils that may not apply in container substrates. In a greenhouse experiment, the substrate-pH change was measured with 18 WSFs that varied in the concentration of NH4-N, NO3-N, urea-N and other nutrients. 'Ringo Deep Red' Pelargonium×hortorum (Bailey. L.H.), 'Super Elfin Bright Orange' Impatiens wallerana (Hook. F.), and 'Ultra Red' Petunia×hybrida seedling plugs were grown in 70%:30% (v:v) peat:perlite substrate amended with dolomitic hydrated limestone. Plants in 900mL, 6-celled containers were top-irrigated with a total of 3.07L over 4 weeks at 100mgL-1 N without leaching. Plant species varied in their pH effect, in the order from acidic to basic of Pelargonium, Impatiens, and Petunia. Fertilizer CCE was positively correlated with substrate-pH, with r2 between 0.54 and 0.80 depending on the species. Multivariate regression also quantified NH4-N, NO3-N, and urea-N concentration effects on substrate-pH and CCE of applied fertilizer. Estimated mequiv. of acid (negative values) or base (positive values) per mmol of each nitrogen form applied were NH4-N -0.6678, -0.6143, -0.8123; NO3-N 0.0713, 0.2746, -0.1296; and urea-N -0.2038, -0.1445, -0.2711 for Impatiens, Petunia, and Pelargonium, respectively. Ammonium-N therefore had a strong acid effect, nitrate-N was a weak base or acid, and urea-N was a weak acid. Calculation of CCE based on PM or nitrogen alone provided a similar R2 with observed pH, despite a wide range in concentrations of macronutrients other than N in the fertilizer blends. Pierre's Method and nitrogen estimates of CCE for fertilizer blends were similar to each other (R2=0.97). However, PM estimates were biased compared with experimental results, over-predicting acidity of high-ammonium fertilizers, and over-predicting basicity of high-nitrate fertilizers. Results indicate that nitrogen form and concentration may provide a simple estimation of the acidity or basicity of blended fertilizers, although research under other growing conditions would be required. Accurate estimation of CCE is important to help growers formulate appropriate fertilizers to balance other factors such as water alkalinity and plant species. © 2013 Elsevier B.V. Source

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