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

valued. These values are used in an equation to form an empirical relationship by the meter’s microprocessor. The reading output (SPAD) is in an arbitrary unit between 0 and 100 that is proportional to the amount of chlorophyll. The chlorophyll meter

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S.B. Wilson, P.J. Stoffella, and D.A. Graetz

Three perennial species, wine sage (Salvia spp. Sell x roenen Schultes `Van Houttei'), blue anise sage (Salvia gauranitica St.-Hil. Ex Benth. `Black and Blue'), and indigo spires salvia (S. longispicata Martius Galeotti × S. farinacea Benth. `Indigo Spires') were transplanted in containers filled with a biosolid-yard waste compost, a commercial peat-based mix, or a mixture of 1 compost: 1 peat-based mix by volume) and grown under ebb-and-flow, drip, or manual irrigation systems. Initial physical, chemical, and elemental analyses of the media indicated that compost alone had higher pH, electrical conductivity (EC), total porosity (TP), bulk density (BD), particle density (PD), N, C, P, Ca, Zn, Cu, Fe, and B; lower initial moisture, Mg and Al; and similar Mn contents than did the 100% peat-based medium. Heavy metal (Cd and Pb) contents of compost did not exceed EPA 503 Rule limits for biosolid usage. After 6 weeks, plants were measured for leaf nutrient content, growth (leaf and stem dry weights, stem lengths), and quality (number of flowers, leaf greenness, and subjective quality ratings). At 6 weeks, plants grown in 50% or 100% compost generally had higher leaf K, P, and Mn; similar N and Ca; and lower Mg, Fe, and Al content than plants grown in the 100% peat-based medium. Plants grown in media amended with compost generally produced similar or slightly smaller plants (stem weight, leaf weight, and stem length) than when grown in peat-based media. Plants irrigated by ebb and flow resulted in higher (`Van Houttei') or similar (`Indigo Spires') dry stem weights than plants irrigated manually or with drip irrigation. Plants grown in compost had leaf SPAD readings (leaf greenness), number of flowers, and visual quality ratings that were generally similar (`Indigo Spires') or slightly reduced (`Van Houttei') than plants grown in peat-based media. However, for each species (except for `Van Houttei' grown in 50% compost using drip irrigation), plants were of marketable quality, regardless of irrigation system or medium. This study suggests that compost may serve as a viable alternative substrate for peat in the production of containerized perennials using ebb-and-flow, manual, or drip irrigation systems.

Open access

Hardeep Singh, Bruce Dunn, Mark Payton, and Lynn Brandenberger

vegetables can be considered an indicator of antioxidant properties. Colonna et al. (2016) used chlorophyll meter readings [soil–plant analyses development (SPAD); Spectrum Technologies, Plainfield, IL] as an indicator of greenness for 10 different green

Open access

Ji-Jhong Chen, Shuyang Zhen, and Youping Sun

intensity transmitted through leaves of plants treated with zero N was greater than that from plants treated with ample N or medium N ( Table 3 ). Negative correlations were found between transmitted red light and readings using the SPAD-502 chlorophyll

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James E. Altland and Charles Krause

Scientific, Waltham, MA). Foliar chlorophyll content was measured with a chlorophyll meter (SPAD-502; Minolta, Ramsey, NJ) 6 WAP, by averaging five readings per single plant replication. Shoot dry weight (SDW) was measured 6 WAP by harvesting all shoot tissue

Free access

Genhua Niu, Denise Rodriguez, and Mengmeng Gu

leachate. At the end of the experiment, leaf greenness or relative chlorophyll concentration (measured as the optical density, SPAD reading, an acronym of Soil and Plant Analyzer Development) was recorded on two fully expanded young leaves per plant for all

Open access

Sara Andrea Moran-Duran, Robert Paul Flynn, Richard Heerema, and Dawn VanLeeuwen

data and SPAD readings were recorded, and the leaflet had to be located in the middle canopy of the tree. The same leaflet was used for both P n and SPAD. Leaf P n was measured using the LI-COR 6400XT portable photosynthesis system (LI-COR Inc

Free access

Sergio Jiménez, Jorge Pinochet, Anunciación Abadía, María Ángeles Moreno, and Yolanda Gogorcena

-Ractivity in 17 commercial and experimental Prunus rootstocks. The results obtained with the screening protocol were compared with leaf SPAD readings obtained under field conditions that induced iron chlorosis. Materials and Methods Plant material

Free access

Soo-Hyung Kim, Jig Han Jeong, and Lloyd L. Nackley

from fully expanded young leaves that covered the cuvette leaf area (2 cm 2 ) with little or no sign of senescence (chlorophyll meter readings: 46 to 66 SPAD units) were used for parameterization and testing of a coupled leaf physiology model for garlic

Free access

Shengrui Yao, Steve Guldan, Robert Flynn, and Carlos Ochoa

temperatures were taken from a nearby weather station that was 80 m from the test plot. Statistical analyses. Leaf color (SPAD) reading, winter survival, and fruit yield data were analyzed using analysis of variance at P ≤ 0.05 with Fisher’s protected least