Rapid Determination of Nitrogen Status in Pansy

Abstract

<jats:p>Two experiments were conducted with pansy (<jats:italic>Viola</jats:italic> ×<jats:italic>wittrockiana</jats:italic> Gams `Bingo Yello') to determine the relationship between foliar nitrogen (% of dry weight) (FN) and either sap nitrate concentration (SN) in petioles or SPAD readings of foliage. FN was highly correlated to SN throughout both experiments (<jats:italic>r</jats:italic> = 0.80 to 0.91). FN was poorly correlated to SPAD readings early in both experiments (<jats:italic>r</jats:italic> = 0.54 to 0.65), but more highly correlated later when visual symptoms of N deficiency were apparent (<jats:italic>r</jats:italic> = 0.84 to 0.90). SN determined with the Cardy sap nitrate meter was a reliable predictor of FN in pansy, while SPAD readings were only reliable after symptoms of N deficiency were visually evident. FN can be predicted with SN using the following equation: log(SN) = 0.47<jats:sup>*</jats:sup>FN + 1.6 [<jats:italic>r</jats:italic><jats:sup>2</jats:sup> = 0.80, n = 132]. Growers and landscape professionals can use SN readings to predict FN levels in pansy, and thus rapidly and accurately diagnose the N status of their crop.</jats:p>

Use of nondestructive sensors to assess nitrogen status in potted poinsettia (Euphorbia pulcherrima L. (Willd. ex Klotzsch)) production

“…All sensor readings increased as N rates increased over time, which corresponds with similar findings in other ornamental crops like begonia, dianthus, geranium, marigold, poinsettia, and zinnia (Altland et al, 2002;Khan et al, 2004;Schuch et al, 1996;Smith et al, 2004;Wang et al, 2012a,b). All sensors showed quadratic responses across treatments over time due to experiment length primarily (Fig.…”

Spent Mushroom Waste as a Media Replacement for Peat Moss in Kai‐Lan (Brassica oleracea var. Alboglabra) Production

“…The plants grown in 100% SMW or in media without NPK amendment suffered from nitrogen deficiency resulting in leaf chlorosis and low SPAD values. Altland et al [40] also confirmed that leaf chlorophyll content is often correlated with the nitrogen content of growth media. Our findings are also supported by a study performed by Altland and Krause [41] in which they observed the differences in SPAD values among growth media.…”

A Comparison of Rapid Potentiometric and Colorimetric Methods for Measuring Tissue Nitrate Concentrations in Leafy Green Vegetables

“…Several authors found that Cardy meter analysis of fresh plant sap was well correlated with several methods of dry tissue extract and analysis for NO 3 -N and suggested the Cardy could provide rapid, precise NO 3 -N measurements for a variety of crops (Altland et al, 2002(Altland et al, , 2003Hartz et al, 1993;Kubota et al, 1996;Rosen et al, 1996;Westcott et al, 1993Westcott et al, , 1998. Authors note that it may be necessary to dilute samples that are beyond the calibration range of the meter (Hochmuth, 1994;Rosen et al, 1996;Westcott et al, 1993), although Rosen et al (1996) found a linear relationship between methods of analysis up to 2000 mgÁL -1 NO 3 -N, suggesting that the linear range of the Cardy meter extends well beyond the high standard concentration.…”

“…Relatively inexpensive and portable ISE nutrient monitoring devices such as the Cardy NO 3 -N meter (Horiba Insruments, Irvine, CA, and Spectrum Technologies, Plainfield, IL) are capable of measuring fresh plant sap NO 3 -N levels directly. Several authors have shown that measurements made with the Cardy meter using nondiluted plant sap were well correlated to conventional methods of NO 3 -N analysis (Altland et al, 2002(Altland et al, , 2003Hartz et al, 1993;Westcott et al, 1998). However, others found Cardy meter NO 3 -N values were consistently higher than values derived from conventional analysis methods unless sap was diluted to account for ionic strength effects and specific ion interferences (Davenport and Jabro, 2001;Errebhi et al, 1998;Hochmuth, 1994;Kubota et al, 1996;Rosen et al, 1996;Westcott et al, 1993).…”