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Noa K. Lincoln, Theodore Radovich, Kahealani Acosta, Eli Isele, and Alyssa Cho

breeding effort ( Sraffa, 2005 ; Willcox, 1954 ). Foliar nutrient analysis is a well-established method ( Munson and Nelson, 1990 ) to assist in the diagnosis of nutrient-related problems (deficiencies, toxicities, imbalances, etc.) of both annual and

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Holly L. Scoggins, Paul V. Nelson, and Douglas A. Bailey

Substrate solution testing is an essential management tool for greenhouse plug production. Current methods of plug solution extraction and testing can be confounded by subjective aspects of their techniques. The press extraction method (PEM) developed at North Carolina State University offers a convenient and timely method of solution extraction. The rooting substrate is brought to container capacity and after a period of one hour, pressing the plug surface with a finger or thumb is sufficient to expel the solution. This series of experiments serves to quantify possible variation that may occur in pH, Electrical conductivity (EC), and nutrient analysis from differing manual extraction forces. A modified press was designed to apply a range of force [53, 71, 89, 106, and 124 N (5.0, 6.7, 8.3, 10.0, and 11.6 lb/inch2)], and sampling protocol consistency was verified. For all three experiments, the range of extraction forces within a single fertilizer rate did not significantly affect solution pH or EC. When testing included a range of fertilizer rates, results were significantly different among the fertilizer rates, demonstrating the method's ability to detect changes in pH and EC resulting from increases in fertility levels. Nutrient analysis (NO3 -, NH4 +, P, K, Ca, Mg, Na, B, Cu, Fe, Mn, and Zn) of solution extracted from two different rooting substrates (peat-based and coir-based) showed no differences within substrates for the range of force treatments.

Open access

Uttara C. Samarakoon and James E. Faust

evaluations were performed to determine the treatment effects on plant tissues. The evaluations included leaf texture analysis, leaf nutrient analysis, and moisture loss. Sampling for each analysis method started 6 weeks following initiation of treatment

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Robert G. Anderson and Robert Hadad

A segment of the greenhouse crop market would like to obtain vegetables and herbs that are certified organic. The technology for the use of biological controls for insects and diseases is well-developed and a significant part of greenhouse vegetable production. Organic fertilizers, however, have not been well-utilized in organic greenhouse vegetable production. Common organic fertilizers were analyzed for the levels of nutrients when mixed with water for use in greenhouse fertigation. Products derived from algae-Algamin (liquid) and Ohrstrom's Garden Maxicrop (powder), Bat Guano, and products derived from fish waste-GreenAll Fish Emulsion (liquid) and Mermaid's Fish Powder, demonstrated nutrient levels comparable to typical water-soluble fertilizers used for greenhouse plant production. Although the organic fertilizers could not be used as a concentrate for injector systems, readings from a conductivity meter were directly related to nitrate nitrogen levels and could be used for fertilizer management in the capillary mat subirrigation system used for plant production.

Open access

Russell Galanti, Alyssa Cho, Amjad Ahmad, and Javier Mollinedo

site to corresponding N tissue analysis. Materials and methods Tissue sampling and nutrient analysis. The materials selected for this study were obtained from plants at two private farms on Hawai’i Island: Pahala (lat. 19°13′40.2″N, long. 155°28′7.8″W

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William R. Argo, Brian J. Weesies, Erica M. Bergman, Michelle Marshal, and John A. Biernbaum

The rhizon soil solution sampler (RSSS) currently is being used for in situ extraction of the soil solution for nutrient analysis of mineral soils used to produce field-grown crops. In this study, laboratory and greenhouse experiments were conducted to test the effectiveness of the RSSS for in situ solution extraction from soilless container root media and to compare an RSSS extraction method for measuring root-medium pH, electrical conductivity (EC), and NO3-N and K concentrations with that measured with the saturated media extract (SME) method. A near 1:1 correlation was found between the pH, EC, and NO3-N and K concentrations measured in the extracted solution of the RSSS and SME method in media without plants and in media from ten species grown using three water-soluble fertilizer concentrations applied by subirrigation. More testing is needed with the RSSS, perhaps using composite samples form several pots for analysis. The RSSS shows promise for nutrient extraction in container-grown crops because it is fast, nondestructive, simple, economical, and has minimal effect on the nutritional status of the medium in the pot.

Free access

Samuel Salazar-García, Isidro J.L. González-Durán, and Martha E. Ibarra-Estrada

This research was carried out from 2004 to 2005 in two commercial ‘Hass’ avocado orchards cultivated under rainfed conditions in a hot subhumid climate of the state of Nayarit, Mexico. The objectives of this study were to: 1) establish the patterns in nutrient concentrations during the lifespan of winter and summer vegetative flush leaves; and 2) validate a methodology based on mathematical functions to identify the appropriate period for leaf sampling to diagnose plant nutrition in avocado considering its two major vegetative flushes. Leaf samples were taken monthly for each vegetative flush, starting when leaf length was 5 cm or greater and concluding at leaf abscission. Starting at vegetative budbreak, winter and summer leaves lived 12.5 and 7.8 months, respectively. Summer flush leaves grew faster and attained greater length than winter leaves. A mathematical model based on the concentration of macro- and micronutrients through the lifespan of avocado leaves was evaluated. This model was used to determine the period when nutrient concentrations became stable and, consequently, to identify the proper leaf sampling period. For the ‘Hass’ avocado in Nayarit, the period for sampling winter flush leaves corresponded to 6.6- to 7.9-month-old leaves (4 Sept. to 13 Oct.). For summer leaves the optimum period was shorter and occurred when leaves were 3.9 to 4.9 months old (5 Dec. to 5 Jan.). The procedure and sampling time obtained here should be tested in other regions.

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Bernadine C. Strik, Amanda Vance, David R. Bryla, and Dan M. Sullivan

rate because the nutrient analysis did not match the percent of N as stated on the product label. Feather meal was applied in two equal split-applications in March and May. In weed mat plots, the feather meal was concentrated in the openings in 2007

Open access

Wendy L. Zellner

fractions of total Si compared with roots and shoots. Because sap analyses using petiole tissue are becoming more frequent for nutrient analysis, the quantification technique needs to be sensitive enough to detect Si in these ranges. Interestingly, Si

Free access

Warren E. Copes, Andrew Ristvey, Patricia A. Richardson, Bruk E. Belayneh, Haibo Zhang, John Lea-Cox, and Chuanxue Hong

Triplicate water samples were collected monthly from nine waterways [eight runoff containment basins (RCBs) and one stream] on four commercial ornamental plant nurseries from February to July, and from one RCB and nursery from April to October. Four RCBs, one per nursery, were actively used as an irrigation water source. Analysis was done for 18 water quality variables, including ammonium–nitrogen (NH4 +–N), nitrate–nitrogen (NO3 –N), ortho phosphate–phosphorus (PO4–P), total-phosphorus (T-P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), aluminum (Al), boron (B), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), pH, total alkalinity (T-Alk), electrical conductivity (EC), and sodium (Na). The degree and rate of monthly change varied considerably between RCBs. Macronutrients generally increased at most nurseries in 1–2 months after fertilizer application particularly in three RCBs (MD21, VA11, and VA12), with levels of N- and P forms exceeding preferred criteria for irrigation water by June and July in VA11 and VA12. Micronutrients fluctuated less but did vary per RCB with the most monthly change occurring in MD21. Even though pH fluctuated, pH tended to remain alkaline or neutral to acidic respective of the RCB during the entire sample period. T-Alk tended to increase over the summer. EC primarily fluctuated in RCBs with high macronutrient levels. Although levels of N- and P forms were mostly suitable by irrigation water criteria, they were frequently above U.S. Environmental Protection Agency (USEPA) nutrient criteria for promoting healthy water environments of lakes and reservoirs, and are discussed.