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| Ferreira,Eric Victor de Oliveira; Novais,Roberto Ferreira; Médice,Bruna Maximiano; Barros,Nairam Félix de; Silva,Ivo Ribeiro. |
| The use of leaf total nitrogen concentration as an indicator for nutritional diagnosis has some limitations. The objective of this study was to determine the reliability of total N concentration as an indicator of N status for eucalyptus clones, and to compare it with alternative indicators. A greenhouse experiment was carried out in a randomized complete block design in a 2 × 6 factorial arrangement with plantlets of two eucalyptus clones (140 days old) and six levels of N in the nutrient solution. In addition, a field experiment was carried out in a completely randomized design in a 2 × 2 × 2 × 3 factorial arrangement, consisting of two seasons, two regions, two young clones (approximately two years old), and three positions of crown leaf sampling. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Eucalyptus; N/P ratio; Nutritional diagnosis; Plant analysis; Soil fertility evaluation; Chlorophyll meter. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000401127 |
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| Benati,Jorge Atílio; Nava,Gilberto; Mayer,Newton Alex. |
| Abstract The objective of this research was to evaluate the technical feasibility of SPAD index in the diagnosis of N status in ‘Esmeralda’ peach. The field trial, with five N rates applied to the soil (0, 40, 80, 120 and 160 kg ha-1 of N as urea form) was conducted in a randomized block design with four replications. During the years 2014, 2015, 2016 and 2017, SPAD readings were carried out with a Minolta SPAD-502 chlorophyll meter, in the leaf middle part, in 40 leaves per plot. The leaf N content determination was performed in CHN-S Elemental Analyzer. SPAD index and leaf N content increased in a linear way in response to increasing N rates applied in soil. There was a positive linear correlation between SPAD index and N concentration in leaves (0.652;... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Prunus persica; Nitrogen fertilization; Chlorophyll meter; Leaf mineral composition. |
| Ano: 2021 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452021000103002 |
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| Costa, Joao Paulo Ramos; Caputti, Gregory de Paula; Galzerano, Leandro; Silva, Wilton Ladeira da; Ruggieri, Ana Cláudia; Malheiros, Euclides Braga. |
| The nutritional status of xaraes palisade grass with SPAD chlorophyll meter and the critical nitrogen sufficiency index (cNSI) in the dry and rainy seasons were assessed. The experiment was conducted in a completely randomized design with four treatments (50, 100, 200 and 400 kg N ha-1), three replicates and two seasons: dry and rainy. All variables had a high nonlinear relationship with their predictors (p < 0.001). Total nitrogen (TN) reached a plateau at doses 262.0 and 514.8 kg of N ha-1 and the concentration of TN in the plant was 1.88 and 1.93% respectively during the rainy and dry season. Relative chlorophyll content (RCC) reached a plateau at 46.05 and 53.65 SPAD units in the rainy and dry seasons, respectively. The production of dry matter (DM)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fertilization; Urochloa brizantha; Chlorophyll meter; Nutritional status; SPAD.. |
| Ano: 2015 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/24854 |
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| Claret M,Marcelino; Urrutia P,Roberto; Ortega B,Rodrigo; Best S,Stanley; Valderrama V,Natalia. |
| Consumption of water contaminated with nitrates is associated with important health effects such as methemoglobinemia and gastric cancer. Intensive agriculture, which uses large quantities of N fertilizer, is the main source of nitrates in water systems. There are several strategies to reduce leaching and increase Nitrogen Use Efficiency (NUE). An experiment was conducted with spring wheat (Triticum aestivum L.) under sprinkler irrigation (center pivot) to determine if adjusted N applications using precision agriculture tools and plant demand resulted in a lower groundwater nitrate load. Evaluated treatments were: produced fertilization (Pr), precision agriculture (Pa), chlorophyll meter (Sm), and control without N (W/N). The ceramic capsule methodology... |
| Tipo: Journal article |
Palavras-chave: Nitrates; Precision agriculture; Chlorophyll meter; Wheat. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000100018 |
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| Giletto,Claudia Marcela; Díaz,Cecilia; Rattín,Jorge Edgardo; Echeverría,Hernán Eduardo; Caldiz,Daniel Osmar. |
| Nitrogen is the most important nutrient in growing potatoes (Solanum tuberosum L.) because either a deficit or excess in its supply can affect yield and quality, resulting in economic losses. To make a rational use of this nutrient, it is necessary to monitor N status during crop development. The green index (IV) could be a valuable method to assess N sufficiency. In experiments with variable N supply, the IV was assessed during crop growth and an N sufficiency index was derived (ISN-IV). The relationship between tuber yield and the IV and ISN-IV was established, as well as the association between the IV and ISN-IV and N concentration in the following varieties: Innovator, Bannock Russet and Gem Russet. During the vegetative growth stage, the IV and ISN-IV... |
| Tipo: Journal article |
Palavras-chave: Nitrogen; Chlorophyll meter; Potato varieties. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000100015 |
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