Use Of Chlorophyll Meter Research Articles

Nitrogen nutrition status of the vine: correlation between N-tester and SPAD chlorophyll indices

Knowledge of the nitrogen nutrition status of the vine is essential for long-term management of its nutrition with the aim of producing high-quality grapes. Measurement of the chlorophyll index is a fast, non-destructive and relatively inexpensive method that provides a good approximation of the nitrogen nutrition status of the vine during the growing season. Several chlorophyll meters are available on the market, each using its own measurement unit. With the aim of popularizing the use of chlorophyll meters, the interpretation thresholds of the SPAD index, measured on the vine at the veraison stage, have been established from correlation with the N-tester index, for which the thresholds are already known.

Pigmentos fotossintéticos como descritores de resposta a adubação organomineral em cana-de-açúcar (Saccharum Officinarum L.)

Sugarcane (Saccharum officinarum L.) comes from the Asian continent. Culture is of enormous importance to the Brazilian economy, being explored throughout the country, with the Southeast, Northeast and South as the largest production centers today. With the growing population, it has been increasingly sought to increase productivity and profitability with the cultivation of sugarcane with the help of agricultural and managerial techniques. Plant productivity is related to photosynthetic efficiency. One of the factors linked to this efficiency is the chlorophyll content, due to its direct connection with the absorption and transfer of light energy. However, the concentration of chlorophylls can be influenced by fertility and fertilization. The objective of this work was to compare the use of chlorophyll meter (Minolta SPAD® 502 and Falker ClorofiLOG® 17 1030) and spectrophotometer for chlorophyll determination in sugarcane fertilized with organominerals and industrial sewage sludge. The experiment was conducted in randomized blocks, with five replications per treatment. The characteristics evaluated were: Cla (chlorophyll a), Clb (chlorophyll b), Car (carotenoids), Clt (total chlorophylls), Cla/Clb (ratio between chlorophyll a and chlorophyll b). All equipment used showed similar responses in terms of chlorophyll concentration in response to fertilization. It was found that, regardless of the treatments, the concentrations of photosynthetic pigments did not vary.

The Use of Chlorophyll Meters to Assess Crop N Status and Derivation of Sufficiency Values for Sweet Pepper.

Chlorophyll meters are promising tools for improving the nitrogen (N) management of vegetable crops. To facilitate on-farm use of these meters, sufficiency values that identify deficient and sufficient crop N status are required. This work evaluated the ability of three chlorophyll meters (SPAD-502, atLEAF+, and MC-100) to assess crop N status in sweet pepper. It also determined sufficiency values for optimal N nutrition for each meter for pepper. The experimental work was conducted in a greenhouse, in Almería, Spain, very similar to those used for commercial production, in three different crops grown with fertigation. In each crop, there were five treatments of different N concentration in the nutrient solution, applied in each irrigation, ranging from a very deficient to very excessive N supply. In general, chlorophyll meter measurements were strongly related to crop N status in all phenological stages of the three crops, indicating that these measurements are good indicators of the crop N status of pepper. Sufficiency values determined for each meter for the four major phenological stages were consistent between the three crops. This demonstrated the potential for using these meters with sufficiency values to improve the N management of commercial sweet pepper crops.

Different Responses of Various Chlorophyll Meters to Increasing Nitrogen Supply in Sweet Pepper.

Intensive vegetable production is commonly associated with excessive nitrogen (N) fertilization and associated environmental problems. Monitoring of crop N status can enhance crop N management. Chlorophyll meters (CMs) could be used to monitor crop N status because leaf chlorophyll (chl) content is strongly related to crop N status. To monitor crop N status, relationships between CM measurements and leaf chl content require evaluation, particularly when excessive N is supplied. The SPAD-502 meter, atLEAF+ sensor, MC-100 Chlorophyll Concentration Meter, and Multiplex sensor were evaluated in sweet pepper with different N supply, throughout the crop, ranging from very deficient to very excessive. CM measurements of all sensors and indices were strongly and positively related to leaf chlorophyll a + b content with curvilinear relationships over the entire range of chl measured (∼0–80 μg cm-2). Measurements with the SPAD-502, and atLEAF+, and of the Multiplex’s simple fluorescence ratio index (SFR) had asymptotic responses to increasing leaf chl. In contrast, the MC-100’s chlorophyll content index (CCI) had a progressively increasing response. At higher chlorophyll a + b contents (e.g., >40 μg cm-2), SPAD-502, atLEAF+ and SFR measurements tended to saturate, which did not occur with CCI. Leaf chl content was most accurately estimated by CCI (R2 = 0.87), followed by the SPAD-502 meter (R2 = 0.85). The atLEAF+ sensor was the least accurate (R2 = 0.76). For leaf chl estimation, CCI measured with the MC-100 meter was the most effective of the four sensors examined because it: (1) most accurately estimated leaf chl content, and (2) had no saturation response at higher leaf chl content. For non-saturating leaf chl content (∼0–40 μg cm-2), all indices were sensitive indicators. As excessive applications of N are frequent in intensive vegetable crop production, the capacity of measuring high leaf chl contents without a saturation response is an important consideration for the practical use of chlorophyll meters.

Derivation of sufficiency values of a chlorophyll meter to estimate cucumber nitrogen status and yield

Chlorophyll meters are a promising approach for monitoring crop N status of intensively-produced vegetable crops. To do so effectively, it is fundamental that the nature and strength of the relationships between chlorophyll measurement and actual crop N status and yield, throughout the whole crop cycle, be evaluated. Another fundamental requirement for the practical use of chlorophyll meters for crop N monitoring is the availability of sufficiency values or ranges, for a given crop, that indicate N deficiency (below the value) or sufficiency (above the value). The SPAD-502 meter was evaluated as an estimator of crop N status and yield in cucumber, and sufficiency values of SPAD measurements were derived for maximum crop growth and for yield. Two crops were grown in soil in a greenhouse in Almeria (SE Spain), in different cropping cycles, in Autumn 2013 (from early September to late November) and in Spring 2014 (from early March to late May). Chlorophyll measurements were made on a weekly basis throughout the crop cycle and relationships were established between measurements and the Nitrogen Nutrition Index (NNI), i.e. the ratio between actual and critical crop N contents, and yield. Sufficiency values for maximum growth were based on the relationships with NNI and sufficiency values for maximum yield were based on linear-plateau relationships with yield. Relationships of SPAD measurements with crop NNI and yield had average coefficients of determination (R2) of 0.59 and 0.55, respectively, for most of the Autumn crop, and R2 values of 0.84 and 0.83, respectively, for most of the Spring crop. In both crops, relationships were weak in the initial vegetative phase and were stronger in the subsequent reproductive and harvest phases. Generally, there were small differences between the sufficiency values for maximum growth and those for yield, and between the three phenological phases. The average sufficiency value for all phenological phases for both maximum growth and maximum yield was 45.2±0.7 SPAD units. This study showed that measurements of the SPAD-502 meter can be used as reliable indicators of crop N status and yield throughout most of the cycle of cucumber in Autumn and Spring growing seasons. The development and application of sufficiency values for maximum growth and maximum yield may improve N management of fertigated cucumber crops with frequent N application, by providing information for adjustments in N fertilization when SPAD measurements deviate from sufficiency values.

Use of Chlorophyll Meters to Assess In-Season Wheat Nitrogen Fertilizer Requirements in the Southern San Joaquin Valley

Use of Chlorophyll Meters to Assess In-Season Wheat Nitrogen Fertilizer Requirements in the Southern San Joaquin Valley

Clorofilômetro no ajuste da adubação nitrogenada em cobertura para o milho de alta produtividade

A avaliação do conteúdo relativo de clorofila nas folhas fornece uma medida indireta do estado nutricional das plantas e pode ajudar os agricultores no ajuste da quantidade de nitrogênio (N) a ser aplicada em cobertura no milho. Objetivou-se neste trabalho validar o uso do clorofilômetro na detecção e correção da deficiência de N ao longo do ciclo vegetativo da cultura. O experimento foi conduzido em parcelas estabelecidas numa lavoura comercial, sendo o estado nutricional das plantas monitorado semanalmente com o uso do clorofilômetro. Os tratamentos incluíram uma testemunha (0kg ha-1) e quatro doses de N em cobertura (45, 90, 135 e 180kg ha-1), considerando-se o índice de suficiência de nitrogênio (ISN) de 0,95, o qual foi monitorado com o clorofilômetro, a partir de um tratamento referência (500kg ha-1 de N). O uso do clorofilômetro indicou a aplicação de N até 180kg ha-1, extrapolando as quantidades requeridas para máxima eficiência técnica (144kg ha-1) ou econômica (105kg ha-1). O estabelecimento de parcelas referência possibilita usar o clorofilômetro como indicador da necessidade de aplicação de N em cobertura durante o ciclo do milho, não obstante, o uso do valor de ISN 0,95 durante todo o ciclo da cultura pode não ser a estratégia mais apropriada.

Estado nutricional em nitrogênio da grama esmeralda avaliado por meio do teor foliar, clorofilômetro e imagem digital, em área adubada com lodo de esgoto

A intensidade da cor verde da folha pode ser alternativa para estimar a concentração de N na planta, devido à relação entre o teor de clorofila e o de N no tecido foliar. Objetivou-se neste trabalho avaliar índices da cor verde da grama esmeralda obtidos da análise da imagem digital e pelo uso do clorofilômetro para predizer o estado nutricional em N fornecido pelo lodo de esgoto. O experimento foi instalado e desenvolvido em uma propriedade comercial de grama esmeralda, localizada na cidade de Itapetininga (SP). O delineamento experimental foi em blocos casualizados, com quatro repetições e cinco doses de lodo de esgoto: 0, 10, 20, 30 e 40 Mg ha-1, base seca. As doses de lodo aplicadas correspondem a 100, 200, 300 e 400 kg ha-1 de nitrogênio disponível. Foram avaliadas as concentrações de N e a intensidade de coloração verde da folha pelo uso do clorofilômetro (ICV) e por meio da análise da imagem digital (G, H e ICVE) aos 45, 105 e 165 dias após a aplicação do lodo. Os valores de intensidade obtidos foram correlacionados com a concentração de N na lâmina foliar e com a taxa de cobertura do solo determinada nas mesmas épocas. A aplicação de doses de lodo de esgoto proporcionou aumento dos índices de cor verde e da concentração de N nas folhas da grama esmeralda. A concentração de N na lâmina foliar pode auxiliar a adubação nitrogenada em cobertura, pois proporcionou altas correlações com a taxa de cobertura do solo. O matiz (H) obtido com a imagem digital e a intensidade de cor verde da folha (ICV) obtida com o clorofilômetro correlacionaram-se com a concentração de N e com a taxa de cobertura do solo e, dessa forma, podem servir como índices na recomendação da adubação nitrogenada.

Sensitivity of Chlorophyll Meters for Diagnosing Nitrogen Deficiencies of Corn in Production Agriculture

Chlorophyll meters have been widely used to diagnose N deficiencies in research trials and to help refine N fertilizer recommendations in production agriculture. The diagnoses are based on the assumption that chlorophyll meters can detect a wide range of N deficiencies under field conditions according to relationships between chlorophyll meter readings (CMRs) and yield responses to N fertilization that are established from small‐plot trials. We conducted a field‐scale study to evaluate the sensitivity of chlorophyll meters when they are used to detect N deficiencies in corn (Zea mays L.) production. The multiple year–location data were gathered in three cornfields where N fertilizer was applied at different rates in strips that crossed several soil map units. Grain yields were related to CMRs taken on corn leaves in June, July, and August of 1998–1999. Results showed that the chlorophyll meters could detect severe N deficiencies early in the season, but small and moderate deficiencies of N could not be diagnosed with reasonable certainty until it was too late to make in‐season fertilization. Two types of discontinuity are discussed in this paper as likely causes for the limited sensitivity of the chlorophyll meters. Our study suggests that problems associated with the use of chlorophyll meters to diagnose deficiencies of N in production agriculture are much greater than their use to help interpret results of well‐controlled research trials where yields are also measured.

Use of Chlorophyll Meter to Assess the Effect of Nitrogen on Sweet Pepper Development and Growth

The evolution of both leaf expansion and chlorophyll content was assessed in potted sweet pepper plants subjected to four different levels of nitrogen (mg N/kg of soil): N1 = 25 (basal dressing); N2 = 50 (basal dressing); N3 = 100 (basal dressing and one side dressing); and, N4 = 150 (basal dressing and two side dressings). In each plant, the first leaves (numbered 1–5) were chosen at the main stem and the next four ramifications. The relative chlorophyll content of leaves 1 to 5, from all treatments, was obtained by a portable chlorophyll meter, SPAD-502, twice a week. The SPAD readings were subsequently converted into total chlorophyll (μ g cm− 2). The plant dry weight, the number of fruits per plant, and the N content of leaves were measured at final harvest (70 d after transplantation, DAT). Until the first side dressing (35 DAT), the increase in chlorophyll content was similar in all treatments, decreasing afterward under the N1 and N2 treatments (leaves 1 and 2), while under the N3 and N4 treatments the increase in the chlorophyll content continued after the first side dressing. The application of the second side dressing (53 DAT) under the N4 treatment induced a subsequent increase in chlorophyll content in all leaves compared with those of N3. An early senescence was observed under the N1 and N2 treatments compared with the others. Applied N in side dressing led to an increase in leaf width (leaves 2–5) and longevity, mainly in leaves 2 and 3, and a subsequent increase under fruit number and fruit dry weight under the N3 and N4 treatments.

The use of hand-held chlorophyll meters as a tool to assess the nitrogen status and to guide nitrogen fertilization of potato crop

Fifteen experiments were carried out in different sites of Italy, Belgium, Scotland and The Netherlands from 1995 to 1999 to study the possible use of chlorophyll meter to assess the nitrogen status and to guide nitrogen fertilization of the potato crop. The results are gathered here and reviewed together with available information in literature. The paper deals with measuring principles of chlorophyll meter; relation between chlorophyll meter readings and analytical measurements of chlorophyll, analytical measurements of nitrogen, crop nitrogen content, tuber yield, and physiological processes in leaves; variations in chlorophyll meter readings related to nitrogen supply, potato cultivar, crop management, and sampling methods; use of chlorophyll meter readings for decision making in the management of supplemental nitrogen fertilization (assessment of chlorophyll meter critical threshold, plant response to addition of supplementary N).

Uso do clorofilômetro como indicador da necessidade de adubação nitrogenada em cobertura no feijoeiro

A adubação nitrogenada é uma prática cultural normalmente utilizada pelos produtores de feijão. O objetivo deste trabalho foi avaliar o uso do clorofilômetro como instrumento indicador da necessidade de adubação nitrogenada em cobertura no feijoeiro, cultivado no inverno, irrigado por aspersão, pelo sistema pivô central. A primeira etapa, realizada em 2000, consistiu no cultivo das cultivares de feijão, Pérola e Jalo Precoce, submetidas a 0, 30, 60 e 120 kg ha-1 de N aplicados em cobertura, com a finalidade de estabelecer curvas de resposta entre as leituras do clorofilômetro, modelo Minolta SPAD-502, em cada dose de N, e a produtividade de grãos. A segunda etapa, realizada em 2001, consistiu em validar, no campo, os valores de leitura do medidor indicativos de nível adequado de N na planta. As produtividades das duas cultivares e as leituras do clorofilômetro aumentaram com o aumento da dose de nitrogênio. Na mesma dose de N, os valores de leitura foram maiores na cultivar Pérola. O clorofilômetro se mostrou eficaz como instrumento indicador da necessidade de adubação nitrogenada em cobertura no feijoeiro.

Using a chlorophyll meter to manage nitrogen applications to corn with high nitrate irrigation water

Chlorophyll meters can aid in measuring the nitrogen (N) status of corn (Zea mays), but will the use of chlorophyll meters decrease total N use or increase corn grain yield? Use of a fully fertilized reference strip with a chlorophyll meter (SPAD 502) is an accepted management strategy. The critical level of relative chlorophyll necessary to trigger supplement N is uncertain. To determine the impact of using a 96 or 92% critical level of chlorophyll readings relative to a fully fertilized reference strip, 0 and 112 N kg ha‐1 were applied at planting for three years. Specific plots were fertilized with an additional 56 kg N ha‐1 whenever the meter reading on those plots was below either 96 or 92% of the reference area. The experiment was conducted on two Typic Haplustolls and an Entic Haplustoll. Irrigation water contained nitrate ranging from 20 to 38 mg L‐1. Irrigation water supplied from 43 to 120 kg N ha‐1 season‐1. For all treatments that received N‐supplements based on the chlorophyll meter, yields were statistically the same. The chlorophyll meter is a useful management tool to help schedule N applications, when irrigation water is contaminated with nitrate since use of the chlorophyll meter prevented any yield limiting N deficiencies.

Use of chlorophyll meter for nitrogen management in lowland rice

The chlorophyll meter (SPAD-502) can be used to diagnose the nitrogen (N) status of rice (Oryza sativa L.) to decide for fertilizer-N side-dressing. The objective of this study was to determine the relationships between SPAD meter readings, unadjusted and adjusted for specific leaf weight (SLW) and N on dry weight basis (Ndw), N on leaf area basis (Na) and yield. The correlation coefficients (r) between SPAD and Ndw ranged from 0.82 to 0.90; between SPAD and yield, from 0.75 to 0.90; and between SPAD/SLW and yield from 0.77 to 0.85 on pooling the data experiment-wise. The corresponding ‘r’ values over all experiments were 0.87, 0.81 and 0.80, respectively. The results of better relationship between SPAD and Ndw; and between SPAD and yield in the late reproductive and early ripening phases allows prediction of plant N status based on direct SPAD meter readings. It is quick, simple and non-destructive unlike N prediction based on Kjeldahl procedure or SPAD/SLW.

Chlorophyll meter readings in corn as affected by plant spacing

Abstract Heightened environmental consciousness has increased the perceived need to improve nitrogen (N) use efficiency by crops. Synchronizing fertilizer N availability with maximum crop N uptake has been proposed as a way to improve N‐use efficiency and protect ground water quality. Chlorophyll meters (Minolta SPAD 502) have the potential to conveniently evaluate the N status of corn (Zea mays L.) and help improve N management. A potential problem with the use of chlorophyll meters is the effect of within‐row plant spacing on meter reading variability. Chlorophyll meter readings and leaf N concentration of irrigated corn at anthesis and grain yield at harvest were measured on plants grouped into eight within‐row plant spacing categories. Leaf N concentration was not affected by plant spacings, but chlorophyll meter readings and grain yield per plant increased as plant competition decreased and N fertilizer rate increased. These data indicate that avoiding plants having extreme spacings can greatly incre...