Quantifying the nonlinearity in chlorophyll meter response to corn leaf nitrogen concentration

Dwyer, L. M.; Stewart, D. W.; Gregorich, E.G.; Anderson, Aaron; L., B.; Tollenaar, M.

doi:10.4141/cjps95-030

Cited by 133 publications

(106 citation statements)

References 3 publications

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“…Figure 7 shows that as the leaf nitrogen concentration increases, the sensitivity of the SPAD to detect leaf N content decreases. This result is consistent with the observations reported by Dwyer et al (1995) and Wood et al (1992). Van don Berg and Perkins (2004) also observed that the accuracy of the portable chlorophyll meters decreases at high readings values.…”

Section: And Discussionsupporting

confidence: 82%

“…7), because at later plant growth stages a larger proportion of the leaf N is eventually associated with the chloroplasts, and there is less nitrate-N in the leaves (Dwyer et al, 1995). Similar results are reported by investigators who studied the relationship between chlorophyll meter readings and plant N concentration at different plant growth stages (Wood et al, 1992).…”

Section: And Discussionsupporting

confidence: 73%

“…The curvilinear response of the SPAD values to canola N concentration may be attributed to: -increase in the proportion of nitrate-N in the total N form at high N levels, which is included in assays of total N, whereas, it is not detected by the chlorophyll meter (Dwyer et al, 1995), and -the effect of drought stress which partially increases the leaf vacuolar pigments affecting the SPAD values (Schepers et al, 1996).…”

Section: And Discussionmentioning

confidence: 99%

“…An easily available instrument, the chlorophyll meter (eg SPAD-502 chlorophyll meter), is used widely to evaluate the plant chlorophyll content and, hence, to estimate the plant N status and deficiencies and, subsequently, to determine the real-time based need for N fertiliser with introducing a proper calibration (Jifon et al, 2005). Experimental relationships between N concentration and SPAD reading values are expressed with linear (Chang and Robison, 2003) or curvilinear (Dwyer et al, 1995) models depending on the crops, the species, the cultivars and the crop growth stage (Esfahani et al, 2008). In addition, any biotic (eg pests, diseases, weeds) and abiotic stresses (eg drought, heat, cold, salinity) may influence the SPAD reading values and, subsequently, the chlorophyll or N estimates (Balasubramanian et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of canola chlorophyll index and leaf nitrogen under wide range of soil moisture

Meskini-Vishkaee¹,

Mohammadi²,

Neyshabouri³

et al. 2015

International Agrophysics

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A b s t r a c t. The paper presents a study on the effect of soil matric suction on the variation of leaf chlorophyll index and nitrogen concentration of canola. Results showed that chlorophyll index increases exponentially with soil matric suction, especially at the late season of canola growing time. At moderate matric suction (200 and 300 kPa soil suction heads), chlorophyll index remains nearly constant, but in drier soil (matric suction >300 kPa), chlorophyll index increases gradually with time. Despite the variation of the total leaf nitrogen with the soil matric suction, it is similar to the variation of the chlorophyll index, but the results showed that the chlorophyll index -nitrogen concentration curve has a demarcated bi-modal shape. We suggest that 2.7% of nitrogen and 69.8 of the chlorophyll index value represent the upper limit of the chlorophyll meter reliability for estimation of canola nitrogen under a wide range of soil moisture levels. These results confirm that the chlorophyll meter can be used as an effective tool for rapid and non-destructive estimation of the relative chlorophyll and nitrogen content in canola leaves at a wide range of soil moisture content, except for nearly wilting coefficient or extremely high drought stress.

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Section: And Discussionsupporting

confidence: 82%

Section: And Discussionsupporting

confidence: 73%

Section: And Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evaluation of canola chlorophyll index and leaf nitrogen under wide range of soil moisture

Meskini-Vishkaee¹,

Mohammadi²,

Neyshabouri³

et al. 2015

International Agrophysics

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“…Quando absorvido em excesso, o N acumula-se como nitrato e nesta forma, não se associa à molécula de clorofila e, portanto, não pode ser detectado pelo medidor (DWYER et al, 1995 ). SILVA et al (2000) obtiveram resposta positiva até a dose de 85 kg ha de N. Essa variabilidade nas respostas a aplicação de N se deve a diversos fatores como quantidade de matéria orgânica presente no solo, a prática ou não da adubação orgânica, ao tipo de solo utilizado, a cultura anterior e também aos níveis das doses aplicadas.…”

Section: Green Hue In Vernalized Garlic Leaves In Response To Nitrogeunclassified

Coloração verde nas folhas da cultura do alho vernalizado em resposta à adubação nitrogenada

et al. 2008

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RESUMOO experimento foi desenvolvido em campo com o objetivo de avaliar a viabilidade do monitoramento da adubação nitrogenada em cobertura, na cultura do alho vernalizado, por meio de medidas indiretas da intensidade de coloração verde nas folhas (medidor de clorofila SPAD), relacionando-as com o estado nutricional das plantas e com a produção de bulbos. O delineamento experimental utilizado foi o de blocos ao acaso, compreendendo seis doses de nitrogênio (0; 20; 40; 80; 160; 320 kg ha -1 ) com cinco repetições. O N foi aplicado parceladamente em cobertura aos 20 e 75 dias após a emergência. Foram obtidos os dados de intensidade de coloração verde (ICV) e teor de N das folhas, massa média, produção total e classificação de bulbos, segundo o tamanho. A concentração de N e a ICV foram influenciadas pelas doses de N. Houve correlação significativa entre a ICV e o teor de N nas folhas e também entre a produção de bulbos e a ICV e entre a produção e o teor de N. O valor máximo de ICV foi alcançado com a dose de 250 kg ha -1 e a produtividade máxima e a massa média de bulbos foram obtidas na dose de 268 kg ha -1 o que pela proximidade desses valores revelam que o medidor de clorofila pode ser utilizado para recomendação da adubação nitrogenada na cultura do alho. Com a dose de 237 kg ha -1 de N, obteve-se maior rendimento em R$. Palavras-chave:Allium sativum L., produção de bulbos, estado nutricional ABSTRACT GREEN HUE IN VERNALIZED GARLIC LEAVES IN RESPONSE TO NITROGEN FERTILIZATIONA field experiment was carried out in order to determine the feasibility of monitoring nitrogen fertilization of vernalized garlic production by means of the correlation between the indirect measurement of the intensity of the green hue of the leaves (SPAD chlorophyll meter) and the plant nutritional condition and bulb yield. A randomized complete block design was used with six doses of nitrogen (0, 20, 40, 80, 160, 320 kg ha -1 ) and five repetitions. Nitrogen rates were side-dressed applied at the 20 th and the 75 th days after emergence. Data were collected for green hue intensity (GHI) and N content of leaves, average weight, total production and bulb classification as per size. Nitrogen concentrations as well as GHI were affected by N rates. Significant correlations were found between GHI and N content of leaves, between bulb production and GHI, and also between output and N contents. The maximum GHI value was attained a N rate of 250 kg ha -1 and the maximum productivity and the maximum average bulb weight were attained at 268 kg ha -1. Given the proximity of these rates, these results indicate that chlorophyll measurement can be used for the recommendation of nitrogen fertilization of garlic cultures. The best economic return was obtained with a 237 kg ha -1 N rate.Key words: Allium sativum L., bulb production, nutritional condition.

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Emissions of nitrogen‐containing organic compounds from the burning of herbaceous and arboraceous biomass: Fuel composition dependence and the variability of commonly used nitrile tracers

Coggon

Veres

Yuan

et al. 2016

Geophysical Research Letters

107

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Volatile organic compounds (VOCs) emitted from residential wood and crop residue burning were measured in Colorado, U.S. When compared to the emissions from crop burning, residential wood burning exhibited markedly lower concentrations of acetonitrile, a commonly used biomass burning tracer. For both herbaceous and arboraceous fuels, the emissions of nitrogen‐containing VOCs (NVOCs) strongly depend on the fuel nitrogen content; therefore, low NVOC emissions from residential wood burning result from the combustion of low‐nitrogen fuel. Consequently, the emissions of compounds hazardous to human health, such as HNCO and HCN, and the formation of secondary pollutants, such as ozone generated by NOx, are likely to depend on fuel nitrogen. These results also demonstrate that acetonitrile may not be a suitable tracer for domestic burning in urban areas. Wood burning emissions may be best identified through analysis of the emissions profile rather than reliance on a single tracer species.

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Quantifying the nonlinearity in chlorophyll meter response to corn leaf nitrogen concentration

Cited by 133 publications

References 3 publications

Evaluation of canola chlorophyll index and leaf nitrogen under wide range of soil moisture

Evaluation of canola chlorophyll index and leaf nitrogen under wide range of soil moisture

Coloração verde nas folhas da cultura do alho vernalizado em resposta à adubação nitrogenada

Emissions of nitrogen‐containing organic compounds from the burning of herbaceous and arboraceous biomass: Fuel composition dependence and the variability of commonly used nitrile tracers

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