Effect of Solution Electrical Conductivity (Ec) and Pre-Plant Nutrient Form on the Ph of a Peat-Perlite Substrate

Fisher, Paul R.; Dickson, Ryan W.; Mohammad-Pour, Gavin S.; Huang, Jinhua

doi:10.17660/actahortic.2014.1034.30

Cited by 14 publications

(12 citation statements)

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“…The acidic biotic effect of fertilizer treatment AF100 enhanced the abiotic effect as seen in the rapid decline in substrate pH throughout the 56 d. Accumulation of fertilizer salts in substrate of the 200 mg · L -1 N series of fertilizer treatments, as seen in rising substrate EC levels, resulted in the biotic fertilizer effect being proportionately smaller than the abiotic effect on substrate pH. This relationship of declining substrate pH with rising fertilizer concentration has been reported by Fisher et al (2014b). Consequently, all substrate pH values were lower in this fertilizer series than in the 100 mg · L -1 N series.…”

Section: Resultssupporting

confidence: 65%

“…However, this does not explain all of the acidic effect since the solution pH of the high concentration acidic PABR fertilizer in this study (6.02) was higher than that of the NF (4.55) and BF (5.82). Influence of fertilizer cations on substrate cation exchange sites plays a major role (Fisher et al, 2014b). Alkaline PABR fertilizers typically have a higher Ca 2+ , and possibly Mg 2+ , but lower NH 4 + content than acidic PABR fertilizers.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Plant Species, Fertilizer Acidity/Basicity, and Fertilizer Concentration on pH of Soilless Root Substrate

Jeong¹,

Nelson²,

Niedziela³

et al. 2016

horts

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The objective of this study was to determine how plant species, fertilizer potential acidity/basicity rating (PABR), and fertilizer concentration affect root substrate pH. Three experiments were conducted. In the first experiment, 13 herbaceous species were grown in a root substrate of three sphagnum peatmoss: one perlite (v/v) with deionized water and a neutral fertilizer (NF) with a PABR of 0 for 78 days to determine species relationships to substrate pH. The decrease in substrate pH ranged from 0.14 to 2.45 units, depending on species. In the second experiment, four of the 13 species from the previous trial representing the range of pH suppression were grown under similar growth conditions as the first experiment for 70 days. Substrate pH was lowered in the range of 0.47 to 2.72 units. In the third experiment, three fertilizers with PABRs of 150 kg·t−1 CaCO3 equivalent alkalinity, 0 neutral, and 193 kg·t−1 CaCO3 equivalent acidity were applied in a factorial design at 100 and 200 mg·L−1 N at each irrigation to kalanchoe (the species with the greatest pH suppression from the previous experiments) for 56 days. When applied at the lower fertilizer rate (100 mg·L−1 N), the PABRs resulted in the final substrate pH levels of 4.68, 5.60, and 6.11 for the acidic fertilizer (AF), NF, and basic fertilizer (BF), respectively. At the high fertilizer rate (200 mg·L−1 N), substrate pH declined continuously to 3.97, 4.03, and 4.92 for the AF, NF, and BF, respectively. Expression of PABR depended on the balance between the abiotic (chemical) effect of the fertilizers vs. the biotic (physiological) effects of the fertilizers on microbes and plants. The PABR was best expressed when the fertilizer supply was just adequate or lower indicating a closer connection to the biotic effect.

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Section: Resultssupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Effect of Plant Species, Fertilizer Acidity/Basicity, and Fertilizer Concentration on pH of Soilless Root Substrate

Jeong¹,

Nelson²,

Niedziela³

et al. 2016

horts

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show abstract

“…The highest substrate-EC occurred with the high rate of OSM (treatment 6) and OSM + DCT (treatment 10). The observed trend whereby high pH treatments tended to have a low EC is consistent with cation exchange of fertilizer cations with protons on the peat substrate (Fisher et al, 2014). Most pH levels were slightly higher than recommended for petunia [5.4 to 6.2 (Fisher, 2003)] during the production phase, although there were no visual signs of iron deficiency ( Fig.…”

Section: Resultssupporting

confidence: 71%

Strategies to Provide Fertilizer for Both Production and Consumer Phases of Petunia

Oliveira

Fisher

Huang

et al. 2016

hortte

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The objective of this study was to compare strategies using water-soluble fertilizers (WSF) and controlled-release fertilizers (CRF) to provide adequate nutrition during both production and consumer phases of petunia (Petunia ×hybrida). Strategies included a CRF with a second prill coating (DCT) that delayed initial nutrient release, compared with a conventional single-coated CRF (OSM) and WSF. Rooted cuttings of petunia were grown for 42 days in trade 1-gal (2.84-L) containers (the “production phase”) with WSF only, a low rate of combined WSF and substrate-incorporated OSM, or low and high label rates of WSF and top-dressed (TD) OSM (WSF + OSM TD), WSF and substrate-incorporated DCT (WSF + DCT), OSM, or a commercial blend of substrate-incorporated OSM and DCT (OSM + DCT). By the end of production phase after 42 days, all fertilizer strategies tested produced horticulturally acceptable plants in terms of chlorophyll index and number of flowers. In a subsequent “consumer phase,” plants were maintained in containers or were transplanted into a landscape and irrigated with clear water for 98 days. Plant performance [number of flowers, SPAD chlorophyll index, dry weight, and tissue nitrogen (N) level] was greater during the consumer phase in treatments with high rates of CRF compared with WSF only or lower rates of CRF. On the basis of nutrient release in a sand substrate without plants at 10, 21, or 32 °C, the DCT had delayed nutrient release compared with single-coated CRF. The release rates of all CRF products and the duration of the delay in release from DCT were temperature dependent. A partial budget found that the lowest cost treatment was WSF only at $0.02/container. Comparing at high application rates, using WSF + DCT ($0.085/container) was more expensive than incorporated OSM ($0.05/container) and had a similar cost to WSF + OSM TD ($0.084/container). The greatly improved consumer performance for plants with residual fertilizer compared with WSF provides an opportunity to add value and profitability if a slightly higher sales price could be obtained. Several fertilizer strategies are available depending on material and labor cost and availability and preferred crop management style.

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“…Other factors such as the displacement of protons from substrate exchange sites by cations in the nutrient solution also buffered substrate-pH, and this acidic substrate cation exchange capacity process may have partially balanced the basic effect of net anion uptake by roots. Fisher et al (2014a) found that addition of Ca 2+ , more than Mg 2+ , NH 4 + , and K + , tended to decrease substrate-pH because of cation exchange with a peat/perlite substrate. Fisher et al (2014b) also found that increasing the concentration of a nitrate-based fertilizer applied to impatiens did not increase substrate-pH, presumably because of cation exchange with a peat/perlite substrate.…”

Section: 1johnson Et Al (2013) Study (Cation/anion Balance)mentioning

confidence: 95%

Solution Ammonium: Nitrate ratio and cation/anion uptake affect acidity or basicity with floriculture species in hydroponics

Dickson

Fisher

Argo³

et al. 2016

Scientia Horticulturae

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Floriculture crops affect substrate-pH and resulting solubility of micronutrients in the root zone during commercial production. Two hydroponic experiments and tissue data from a container study were analyzed to determine whether (1) cation or anion uptake was related to solution acidity and basicity in the root zone for three floriculture crops [geranium (Pelargonium x hortorum, Bailey. L.H.), petunia (Petunia x hybrid, Vilm.-Andr.), and impatiens (Impatiens wallerana, Hook. F.)] and whether (2) the proportion of NH 4 +-N versus NO 3-impatiens and 20% NH 4 +-N for petunia would be expected to result in a neutral pH response in a hydroponic solution with zero alkalinity. Evaluating cation/anion uptake ratio across a range of NH 4 + :NO 3 ratios could be used to predict the relative acidity or basicity of other plant species to assist in pH management.

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Effect of Solution Electrical Conductivity (Ec) and Pre-Plant Nutrient Form on the Ph of a Peat-Perlite Substrate

Cited by 14 publications

References 0 publications

Effect of Plant Species, Fertilizer Acidity/Basicity, and Fertilizer Concentration on pH of Soilless Root Substrate

Effect of Plant Species, Fertilizer Acidity/Basicity, and Fertilizer Concentration on pH of Soilless Root Substrate

Strategies to Provide Fertilizer for Both Production and Consumer Phases of Petunia

Solution Ammonium: Nitrate ratio and cation/anion uptake affect acidity or basicity with floriculture species in hydroponics

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