Establishment of Calibration Curves for Comparing Pour-through and Saturated Media Extract Nutrient Values

Cavins, Todd J.; Whipker, Brian E.; Fonteno, William C.

doi:10.21273/hortsci.39.7.1635

Cited by 26 publications

(20 citation statements)

References 17 publications

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“…The lowest pH range in WSF (4.5 to 3.8) occurred between 95 and 145 DAT, and CRFs registered pH values between 5.3 and 7.5. The decreased pH with WSF was due to the N soluble fertilizer applications as ammonium nitrate because the roots when absorbing ammonium simultaneously exude H + as a way of maintaining the electrochemical equilibrium of the rhizosphere and the constancy of the intracellular pH (Cavins et al, 2004). In addition, NH 4 + not absorbed by the roots can suffer a nitrification process that acidifies the rhizosphere (Borgognone et al, 2013).…”

Section: Resultsmentioning

confidence: 99%

Controlled-release Fertilizers Improved Croton Growth and Reduced Nitrogen Leaching

Braghin¹,

Mello²,

Angelotti-Mendonça³

et al. 2019

horts

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Fertilizer management is an essential step in the production process, as it allows the plant to use its productive capacity to the fullest extent possible. Researchers have tested maximum nutrient use with reduced losses to the environment aiming to increase productivity with fewer environmental impacts. This study compared the effects of controlled-release fertilizers (CRFs) with water-soluble fertilizer (WSF) and clear water (control) on the growth and nutrient uptake of croton (Codiaeum variegatum L.) and nitrogen leaching. The experiment was conducted with three replications and six treatments: two rates (1.5 g and 3.0 g per liter of substrate) of two CRFs [Osmocote Plus (15% N, 3.93% P, and 9.96% K) and Basacote (15% N, 3.49% P, and 9.96% K)], WSF, and clean water as control. All CRFs were applied before planting and WSF was supplied as nutrient solution through automated moisture sensor activated irrigation system. Plant growth (number of leaves, leaf area, stem height, root volume, and shoot and root dry weights) and total nutrient contents in the leaf tissue were evaluated every 30 days. Electrical conductivity (EC), pH, nitrate, ammonium, and total nitrogen contents were measured in the leached solution. Indeed, results showed that CRFs at a low rate provided similar development and quality of croton plants compared with WSF. Plant growth indicators were similar until 90 days after transplanting (DAT). After that, at 150 DAT, the highest values to number of leaves and leaf area occurred with WSF and with the lowest CRF rate as compared with the other treatments and control. The highest root volume was found with the WSF, which resulted in larger roots compared with the other treatments. These results showed WSF can be replaced by CRFs at low rates on croton growth. Moreover, according to the visual scale, the best treatments were WSF and Basacote at the low rate, where plants were bright, with multicolored leaves with prominent orange shades. However, CRFs maintained pH and EC within the recommended range for the growth of croton and reduced the nitrogen leaching from the pots.

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Section: Resultsmentioning

confidence: 99%

Controlled-release Fertilizers Improved Croton Growth and Reduced Nitrogen Leaching

Braghin¹,

Mello²,

Angelotti-Mendonça³

et al. 2019

horts

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“…'Limelight', Ilex crenata 'Helleri', Rhododendron L. 'Karen' (Shreckhise et al, 2018), Tagetes erecta L. 'Inca Gold' (Tolman et al, 1990) and Euphorbia pulcherrima Willd. Ex Klotzch 'Freedom Red' (Cavins et al, 2004). Thus, relatively high PWP concentrations at 16 DAI of plants in the 0.1 g P treatment may be attributed to a relatively low P uptake rate by roots since roots were not likely yet established.…”

Section: Middle Atlantic Coastal Plainmentioning

confidence: 95%

Growth response of Hydrangea macrophylla and Ilex crenata cultivars to low-phosphorus controlled-release fertilizers

Shreckhise

Owen

Niemiera

2019

Scientia Horticulturae

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In containerized nursery-crop production, conventional phosphorus (P) fertilization amounts are reported to be in excess of plant needs which has resulted in poor P use efficiency (PUE) and subsequent P leaching from containers. Phosphorus leaching can be reduced and PUE improved without affecting plant growth by reducing P fertilization. The objective of this study was to identify the lowest controlled-release fertilizer (CRF)-P content and subsequent pour-through-extracted substrate pore-water P (PWP) concentration that produces maximal shoot growth of two common container-grown nursery crop species, Hydrangea macrophylla 'PIIHM-II' (hydrangea) and Ilex crenata 'Helleri' (holly), in a pine bark substrate. Hydrangea and holly liners were potted into 3.8-L containers containing a pine bark substrate and grown simultaneously in two different Virginia ecoregions, Middle Atlantic Coastal Plain (MACP) and Ridge and Valley (RV). Plants were fertilized with one of five CRF formulations, each containing equal nitrogen (N) and potassium (K) and 0.4%, 0.9%, 1.3%, 1.7% or 2.6% (control) P to supply containers with 0.1, 0.2, 0.3, 0.4 or 0.6 g P, respectively. In both ecoregions, hydrangea shoot dry weight (SDW) and growth index [i.e., (widest width + perpendicular width + height) ÷ 3, GI] values were maximal in plants fertilized with 0.3 to 0.4 g P or the control. The lowest CRF-P rate needed for maximal SDW and GI of holly was 0.2 g P at the RV site and 0.4 g P at the MACP site. Mean PWP concentrations that corresponded with highest SDW were as low as 0.8 and 1.2 mg L −1 for hydrangea and holly, respectively. Results from this research suggest hydrangea requires approximately half the P rate supplied by recommended rates of conventional CRFs. Since the growth response of holly to CRF-P rate at the MACP site was inconsistent with results observed at the RV site and findings in scientific literature, further research is needed to determine the minimum required CRF-P rate for this taxon.

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“…For many fl oriculture and greenhouse crops, current substrate pH and electrical conductivity (EC) interpretation ranges are based on three substrate solution extraction methods: 1) 1 substrate : 2 water (by volume) suspension (1:2 dilution) (Sonneveld, 1990); 2) the saturated media extract (SME) method (Warncke, 1986); or 3) the pour-through extraction method (Cavins et al, 2004;Wright, 1986). The fi rst two methods are generally used by analytical labs, while the pour-through method was developed as a quick and inexpensive test that can be performed in the greenhouse or nursery.…”

mentioning

confidence: 99%

In Situ Probes for Measurement of Electrical Conductivity of Soilless Substrates: Effects of Temperature and Substrate Moisture Content

Scoggins¹,

Iersel²

2006

HortSci

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Growing medium electrical conductivity (EC) is used in laboratory analysis and greenhouse production as a measure of the nutrient content of the growing medium. Fast, accurate ways to measure growing medium EC will make it easier to determine EC and maintain it within a suitable range for a particular crop. Several probes have been developed that can be inserted directly into the growing medium of container-grown crops for measurement of EC. We tested the sensitivity of four in situ EC probes (Field Scout, HI 76305, WET sensor, and SigmaProbe) at a range of temperatures, substrate volumetric water contents (VWC), and fertilizer concentrations. The HI 76305 probe was highly sensitive to temperature, while the WET sensor was temperature-sensitive at high ECs above its normal operating range. The probes responded differently to increasing VWC. The SigmaProbe and WET sensor measure the EC of the pore water specifically and show a decrease in EC with increasing water content, as the fertilizer ions in the pore water become more diluted as VWC increases. EC readings of the HI 76305 and Field Scout probes, which measure the EC of the bulk substrate (growing medium, water, and air combined) increased with increasing water content as the added water helps conduct the current of these meters. At a VWC above 35%, there was little effect of VWC on EC readings of all probes. The EC measured with the various in situ probes differed slightly among the probes but was highly and positively correlated with all three of the standard solution extraction methods [pour-through, 1:2 dilution, and saturated media extract (SME)] over the range of fertilizer concentrations at a given temperature and VWC. These results make it possible to convert substrate EC guidelines that have been established for any of the three standard methods for use with the in situ probes, though our results indicate the substrate VWC must be above 35% for the interpretation to be valid. The in situ probes are a viable alternative for measurements of substrate EC and eliminate the step of substrate solution extraction, thus simplifying data collection.

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Establishment of Calibration Curves for Comparing Pour-through and Saturated Media Extract Nutrient Values

Cited by 26 publications

References 17 publications

Controlled-release Fertilizers Improved Croton Growth and Reduced Nitrogen Leaching

Controlled-release Fertilizers Improved Croton Growth and Reduced Nitrogen Leaching

Growth response of Hydrangea macrophylla and Ilex crenata cultivars to low-phosphorus controlled-release fertilizers

In Situ Probes for Measurement of Electrical Conductivity of Soilless Substrates: Effects of Temperature and Substrate Moisture Content

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