Field evaluation of the chlorophyll meter to predict yield and nitrogen concentration of switchgrass

Madakadze, I. C.; Stewart, Katrine A.; Madakadze, R.; Peterson, Paul; Coulman, Bruce; Smith, Donald L.

doi:10.1080/01904169909365689

Cited by 36 publications

(21 citation statements)

References 15 publications

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“…Recentemente, foi demonstrado a potencialidade do SPAD-502 para avaliar a resposta de diversas espécies à aplicação do nitrogênio (Hoel & Solhaug, 1998;Wu et al, 1998;Sainz-Rozas & Echeverria, 1998;Madakadze et al, 1999;Carreres et al, 2000;Sandoval-Villa et al, 2000).…”

Section: Abstract Spad Index For Nitrogen Status Diagnosis and Potatounclassified

Índice SPAD para o diagnóstico do estado de nitrogênio e para o prognóstico da produtividade da batata

Gil

Fontes²,

Cecon³

et al. 2002

Hortic. Bras.

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A juste no programa de fertilização nitrogenada de uma cultura pode ser conseguido por correto monitoramento e diagnóstico do estado nutricional das plantas (Huett et al., 1997) que envolve tradicionalmente a análise dos teores de N na matéria seca de folhas e posterior interpretação dos resultados. Porém, a utilização da aná-lise foliar apresenta limitações, como o tempo gasto entre a tomada das amostras e a obtenção dos resultados. Atualmente, como parte da agricultura de precisão, é necessário o sensoriamento em tempo real do estado de nutrientes da planta. Dentre as técnicas mais recentes com potencial para avaliar o estado de nitrogênio da planta em tempo real destaca-se a análise da intensidade do verde das folhas, pelo fato de haver correlação significativa entre a intensidade do verde e o teor de clorofila com a concentração de N na folha. Em doze espécies de plantas, Marquard & Tipton (1987) ), aplicadas em cobertura, 10 cm ao lado das plantas, aos 23 dias após a emergência (DAE), imediatamente antes da amontoa. Foi utilizado o sulfato de amônio. Foram feitas medições do índice SPAD no folíolo terminal da quarta folha a partir do ápice (QF) em seis épocas. A primeira (SPAD1) foi realizada três dias antes da adubação em cobertura e as demais aos 7; 17; 27; 37 e 47 dias após a aplicação de N em cobertura. Também foram determinados os índices SPAD em folhas mais velhas (FM) que a QF. Na primeira época foram determinados os teores de N na QF. O índice SPAD1 e o teor de N aumentaram de forma quadrática em função das doses de N em pré-plantio, atingindo os níveis críticos de 44,9 unidades e de 6,2 dag.kg -1 , respectivamente. Houve correlação linear e positiva entre os valores do índice SPAD1 e os da produção de tubérculos, indicando que o índice SPAD pode ser usado no prognóstico da produtividade da cultura. Em todas as épocas de amostragens, os índices SPAD na QF e na FM foram influenciados pelas doses de N porém, atingiram valores diferentes, mostrando a necessidade de padronizar a época e a folha a ser amostrada. Palavras-chave:Solanum tuberosum, clorofila, tubérculos, nível crítico. ABSTRACT SPAD index for nitrogen status diagnosis and potato yield prognosisThe SPAD critical level (Soil Plant Analysis Development) in potato leaves was established to verify the possibility of its utilization in Monalisa potato tuber yield prognosis. The experiment was installed in a Red-Yellow Argisoil having 39 mg kg -1 of mineral nitrogen content. The experiment was laid out in randomized complete blocks with split plot design and four replications. In the plot were set five N rates (0; 25; 50; 100 and 200 kg ha -1 ), applied in the furrows before planting. In the split plot were set four side-dressed N rates (0; 90; 180 and 360 kg ha -1 ), applied in bands 10 cm apart plant side at 23 days after plant emergence, before hilling. SPAD indices were obtained from the terminal leaflet of the fourth leaf from the apex (QF) for six times. The first one (SPAD1) was measured three days before the side-dress N fertilization an...

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Section: Abstract Spad Index For Nitrogen Status Diagnosis and Potatounclassified

Índice SPAD para o diagnóstico do estado de nitrogênio e para o prognóstico da produtividade da batata

Gil

Fontes²,

Cecon³

et al. 2002

Hortic. Bras.

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“…In green vegetation, N absorption features are obscured by strong water absorption bands that are centered at 1450 nm and 1940 nm [21,22]. Because N correlates with chlorophyll in green leaves [23][24][25], although this relationship is influenced by variables such as species and phenology, the spectral features of chlorophyll in visible and red-edge bands can be used as indicators of crop N. Many N spectral indices have been proposed using these features [1,26]. To estimate biomass using remote sensing, the spectral band, which is significantly influenced by the leaf area index (LAI), can be used because biomass strongly correlates with the LAI.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Two Approaches for Estimating the Wheat Nitrogen Nutrition Index Using Remote Sensing

Chen

2015

Remote Sensing

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Remote predictions of the nitrogen nutrition index (NNI) are useful for precise nitrogen (N) management in the field. Several studies have recommended two methods for estimating the NNI, which are classified as mechanistic and semi-empirical methods in this study. However, no studies have been conducted to thoroughly analyze and compare these two methods. Using winter wheat as an example, this study compared the performances of these two methods for estimating the NNI to determine which method is more suitable for practical use. Field measurements were conducted to determine the above ground biomass, N concentration and canopy spectra during different wheat growth stages in 2012. Nearly 120 samples of data were collected and divided into different calibration and validation datasets (containing data from single or multi-growth stages). Based on the above datasets, the performances of the two NNI estimation methods were compared, and the influences of phenology on the methods were analyzed. All models that used the mechanistic method with different calibration datasets performed well when validated by validation datasets containing single growth or multi-growth stage data. The validation results had R 2 values between 0.82 and 0.94, root mean square error (RMSE) values between 0.05 and 0.17, and RMSE% values between 5.10% and 14.41%. Phenology had no effect on this type of NNI estimation method. However, the semi-empirical method was influenced by phenology. The performances of the models established using this method were determined by the type of data used for calibration. Thus, the mechanistic method is recommended as a better method OPEN ACCESSRemote Sens. 2015, 7 4528 for estimating the NNI. By combining proper N management strategies, it can be used for precise N management.

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“…Authors of numerous papers showed a close correlation between the level of these pigments and nitrogen content in leaves determined by the dose and time of fertilization (Baghour et al 2000;Biczak et al 1998;Smith 1999;Swiader and Moore 2002).…”

Section: Introductionmentioning

confidence: 99%

Different species of basil need different ammonium to nitrate ratio in hydroponics' system

Saadatian

Ramezani-Kharazi

2015

AAS

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Basil is a very important medicinal plant and culinary spice, and is marketed fresh, dried or frozen. In crop nutrition, nitrogen is essential for plant growth and as a macro-element, is part of the proteins' structure and participates in the metabolic processes involved in the synthesis and energy transfer. It has been shown that a balance between ammonium and nitrate favors plant growth and that the degree of benefit varies among crops. This study was conducted to evaluate the growth of two varieties of basil in function of four nutrient solutions containing different NH 4 + /NO 3 -ratios. Results showed that different variety response differently to nutrient solution. Although the highest yield in both varieties (sweet and purple) was obtained when fed by nutrient solution without ammonium but their response on quality indices were different due to nitrate ammonium ratio in nutrient solutions. The highest total phenol content of sweet and purple basil was 92 and 100 mg gallic acid equivalent per gram of dry weight respectively, while the highest antioxidant capacity was obtained in purple variety grown in nutrient solution 2 (NH 4 + :1/NO 3 :4) and the lowest value were related to sweet variety with the same nutrient solution. Moderate content of total nitrogen can be suitable for sweet variety while for purple variety nutrient solution with low amount of ammonium can be more suitable. Bazilika je zelo pomembna zdravilna rastlina in začimba, ki se prodaja sveža, suha ali zmrznjena. V prehrani rastlin je dušik esencialni makroelement, potreben za rast, sintezo beljakovin, druge presnovne procese in pretvorbo energije. Znano je, da ravnovesje med amonijsko in nitratno obliko dušika izboljšuje rast in, da se njuno ugodno razmerje spreminja glede na posamezne rastline. V raziskavi smo ovrednotili rast dveh biotipov širokolistne bazilike (zeleno-in vijoličnolistno) v štirih hranilnih raztopinah, ki so vsebovale različna razmerja NH 4 + /NO 3 -. Rezultati so pokazali različen odziv obeh biotipov na razmerja hranil v raztopinah. Čeprav je bil pridelek obeh (zelene in vijolične) največji v hranilni raztopini z amonijsko obliko dušika, so kvalitetni kazalci variirali glede na razmerja nitrata in amonija. Največja vsebnost celokupnih fenolov v zeleni in vijolični baziliki je bila 92 in 100 mg ekvivalenta galne kisline na gram suhe mase, vendar je bila največja antioksidativna sposobnost dosežena pri vijolični baziliki, ki je rastla v hranilni raztopini 2 (NH 4 + :1/NO 3 :4) in najmanjša vrednost pri zeleni baziliki, ki je uspevala v isti hranilni raztopini. Zmerna vsebnost celokupnega dušika je primerna za gojenje zelene širokolistne bazilike, medtem ko je za gojenje vijolične primernejša hranilna raztopina z manjšo vsebnostjo amonija.

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Field evaluation of the chlorophyll meter to predict yield and nitrogen concentration of switchgrass

Cited by 36 publications

References 15 publications

Índice SPAD para o diagnóstico do estado de nitrogênio e para o prognóstico da produtividade da batata

Índice SPAD para o diagnóstico do estado de nitrogênio e para o prognóstico da produtividade da batata

A Comparison of Two Approaches for Estimating the Wheat Nitrogen Nutrition Index Using Remote Sensing

Different species of basil need different ammonium to nitrate ratio in hydroponics' system

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