Factors affecting potato petiole sap nitrate tests

Vitosh, M. L.; Silva, George H.

doi:10.1080/00103629609369622

Cited by 33 publications

(29 citation statements)

References 13 publications

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“…Given the effects of sampling procedure of petioles, diurnal variation of PSNC (Williams and Maier 1990a;MacKerron et al 1995;Vitosh and Silva, 1996;Zhang et al 1996;Errebhi et al 1998b) and the effect of the sampled leaf on PSNC values (Jones and Painter 1974;Millard and MacKerron 1986;MacKerron et al 1995) can be overcome by a rigorous and well described sampling procedure as described by Goffart et al (2000).…”

Section: Petiole Sap Nitrate Concentration (Psnc)mentioning

confidence: 99%

Potato Crop Nitrogen Status Assessment to Improve N Fertilization Management and Efficiency: Past–Present–Future

2008

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Improving nitrogen use efficiency is important for the potato crop, because of its relatively low ability to take up available soil mineral nitrogen (N). Splitting of N fertilizer application is a suitable approach to better match N need and supply. In-season crop N monitoring methods are therefore required to support such strategies. This paper deals with the state of the art and potential development of characteristics, use and implementation of well known and more recent methods aimed to assess in-season potato Crop Nitrogen Status (CNS). A short overview of this concept is given for the potato crop. The most important and available methods for CNS assessment are evaluated for their accuracy, precision, sensitivity, sensibility and feasibility. These are: the petiole sap nitrate concentration test; the leaf chlorophyll concentration measurement using a handheld chlorophyll meter; the measurement of crop light reflectance through a hand-held radiometer using passive sensors. More recent methods still under investigation based on near, ground-based, air-borne or space-borne remote sensing are discussed for their scientific and practical interest in the near future. The current and potential use and implementation of these methods into decision support systems for potato N fertilization management aimed at improving the potato crop nitrogen use efficiency are analysed by: comparing relative and raw data; establishing threshold values of CNS; and combining or integrating the CNS values into models dedicated to N recommendation or to crop growth simulation.

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Section: Petiole Sap Nitrate Concentration (Psnc)mentioning

confidence: 99%

Potato Crop Nitrogen Status Assessment to Improve N Fertilization Management and Efficiency: Past–Present–Future

2008

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“…Solving the equations for a random value of DAE reaches the critical level for this DAE. To enable an easier result interpretation, Table 4 also includes critical values obtained by solving the equations for regular intervals of the growth season (15,25,35, and 45 DAE). The analytical method provided critical levels higher than the graphical one.…”

Section: Rodriguesmentioning

confidence: 99%

“…Critical concentrations of petiole NO 3 -N (laboratory analysis), determined by Cate-Nelson graphical method, varied from 25.7 to The four right columns are the critical levels estimated for dates of sampling defined at regular intervals (15,25,35,and 45 DAE) and are included for exemplification.…”

Section: Rodriguesmentioning

confidence: 99%

Establishment of Continuous Critical Levels for Indices of Plant and Presidedress Soil Nitrogen Status in the Potato Crop

Rodrigues¹

2005

Communications in Soil Science and Plant Analysis

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Critical levels for six plant and pre-sidedress soil nitrogen indices were established for the growing season and their relative accuracy to diagnose the need for supplemental sidedress N was also compared. Field trials were conducted from 1996 to 1998 with irrigated potato in North-eastern Portugal. Fertilizer treatments included several pre-plant and sidedress N rates. Petiole nitrate concentrations (determined by a standard laboratory method and with the portable RQflex reflectometer), leaf N content, leaf greenness (SPAD-502 chlorophyll meter), pre-sidedress soil NO 3 -N and pre-sidedress soil inorganic-N (NO 3 -N + NH 4 -N) were selected as N indicators. The Cate-Nelson graphical method and an analytical procedure using Mitscherlich type curves were used to determine critical levels. In both cases, a yield reduction of 10 % was accepted. The accuracy of the diagnostics was estimated from the Cate-Nelson graphical method, quantifying the point percentage that appears in negative quadrants (the error rate). The graphical method yielded lower critical levels, appearing as the The N indicators with lower error rate were the pre-sidedress soil NO 3 -N and pre-sidedress soil inorganic-N (both showing an error rate of 8.3 %), followed by petiole nitrate concentration (determined in laboratory, 12.0 %, and with RQflex reflectometer,12.5 %), leaf N content (13.0 %) and leaf greenness (14.6 %). Error rates were similar throughout the growing season, meaning that is possible to get information about the need for supplementary N in the very early growth stages.

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“…The petioles proved to be the most suitable plant structure for tissue analyses of potatoes (MacKerron, et at., 1995). The usefulness of tissue analyses is, however, often limited as a result of the long time lapse from sampling to when the results are available (Vitosh & Silva 1996). Producers and consultants would prefer a quick test to determine the NO; -N in fresh sap, enabling immediate recommendations on N-fertilisation.…”

Section: Introductionmentioning

confidence: 98%

Evaluation of petiole nitrate measurement as an aid for N fertilization of potatoes (Solanum tuberosum L.) on sandy soils

Brink

Combrink

Knight³

2002

South African Journal of Plant and Soil

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Potatoes are produced in the Sandveld of the Western Cape on soils with extremely low clay and organic material contents. A low nitrogen mineralisation potential and high leaching hazard complicate the management of the nitrogen supply to the plant. This study investigated the viability of a rapid field measurement of plant nitrate content as a decision support tool in three field trials. In the first two trials the standard practice of weekly Nand K fertigation was used at four different N-Ievels on two cultivars. The nitrate levels were monitored in petioles during two seasons, using two different techniques. The procedure in which dried petioles were used for nitrate extraction and laboratory readings taken with an auto-analyser was less accurate than that where petiole sap was squeezed from petioles and indicator paper strips used for nitrate determination. The highest petiole nitrate levels in these trials corresponded with the highest tuber yields for both cultivars and were found at an application of 400 kg N ha-'. Increasing N levels (100 -400 kg N ha-') significantly reduced the specific gravity (SG) of Hertha but had no effect on the SG of Up-to-Date. With three irrigation treatments and three fertigation frequencies In another trial, the petiole nitrate concentrations were the highest when no leaching occured. The highest petiole nitrate concentration was obtained with two fertigations per week. The petiole nitrate levels differed between cultivars and peaked at five to six weeks after planting. These factors should be kept in mind when petiole nitrate readings are used as an aid for fertiliser programs. The Merck reflectoquant proved to be a viable decision support tool in the N management of potatoes under these conditions. Aartappels word in die Sandveld (Wes-Kaap) geproduseer op gronde met 'n uiters lae klei-en organiesemateriaalinhoud. Verdere kompliserende faktore by die beheer oor die stikstofvoorsiening aan die plant is 'n lae mineralisasiepotensiaal en 'n groot logingsrisiko. Hierdie studie het die lewensvatbaarheid van 'n vinnige veldbepaling van plante se nitraatinhoud as 'n besluitnemingshulpmiddel in drie veldproewe ondersoek. in die eerste twee prof!we is die standaardpraktyk van N-en K-sproeibemesting gebruik by vier verskillende N-vlakke by twee kultivars. Die nitraatvlakke in die blaarpetiole is twee seisoene lank gemonitor volgens twee verskillende tegnieke. Die prosedure, waarvolgens gedroogde petiole gebruik is vir nitraatekstraksie en laboratoriumlesings geneem is met 'n outo-analiseerder, was minder akkuraat as wanneer petioolsap uitgedruk is en papierstrokies gebruik is vir nitraatbepaling. In hierdie proewe het die hoogste petiool-nitraatvlakke ooreengestem met die hoogste knolopbrengs vir altwee kultivars en is dit aangetref by 'n toediening van 400 kg N ha-1 Verhoogde N v/akke (100 -400 kg N ha-') het die soortlike gewig (SG) aansien/ik verlaag in die geval van Hertha maar het geen effek op Up-to-Date se SG gehad nie. In 'n ander proef waar drie besproeiingsbehandelings en dri...

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Factors affecting potato petiole sap nitrate tests

Cited by 33 publications

References 13 publications

Potato Crop Nitrogen Status Assessment to Improve N Fertilization Management and Efficiency: Past–Present–Future

Potato Crop Nitrogen Status Assessment to Improve N Fertilization Management and Efficiency: Past–Present–Future

Establishment of Continuous Critical Levels for Indices of Plant and Presidedress Soil Nitrogen Status in the Potato Crop

Evaluation of petiole nitrate measurement as an aid for N fertilization of potatoes (Solanum tuberosum L.) on sandy soils

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