Índices de nitrogênio e de crescimento do tomateiro em solo e em solução nutritiva
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Data
2001-04-12
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Resumo
O objetivo cios experimentos tai determinar os índices de nitrogénio (leitura SPAD e teores dc nitrato na seiva e dc nitrogênio orgânico na ua iria seca da folha acima do priffleiro Cacho) e dc crescimento (altura de planta, diâmetro dto caule, ám.á e peso da filha acima do piiineiro cacho) no início da 1ise reprodutiva do tomateiro, cultivado em solo e em soluçiio nutritiva_ C) dclinc4uiicnlo nos dais experimentos foi de blocos ao acaso, com quatro repetições. No primeiro, o tomateiro foi transplantado em vaso contendo 3,0 L cis solo at IEtxídt) coin cinco dose:; cie N í), 1002 2Q0, 400 e 800 mg/dm^3). No segundo, o tomateiro 1òï transplantado cm vaso contendo 8 L de so uçáo nutritiva com as doses de N dc c), 4, 8, t 2 e 1 6 rnmol./ï,.Aus 37 e 42 cias após o transplante, no inicio do florescimento do primeiro cacho, os experinientos em solução nutritiva e em solo foram, respectivamente, encenados. Nestas ocasiões, tbia.m determinados a altura rig planta., o diâmetro do caule, a Area e o peso da folha acima do primciro cacho (FAC), o teor de N-NOna seiva do pecíoloe o úndicc Sl'11.1 ) da MC. Em seguida, as plantas foram coÍhidas, separadas em folhas e caule, secas e icsadas. Na matéria seca cia FAQ foi determinado o teor de N-orgânico. Os indices dc nitrogénio (IN) e de crescimento (IG), associados a 99,9% da mama produção de matéria seca cia parte aérea, em ambos os substratos, sãa apresentados. tis IC ferram maiores em plantas que cresceram em soluçâo nutritiva que naquelas que cresceram no solo; o inverso foi verificado nos IN, exceto o teor de Norgânico. Propõe-se due a altura da planta possa ser usada no prognóstico da produçâo de matéria seca da parte aérea e que o peso da matéria fresca e a área da FAC possam ser utilizados na estimativa do estado nutricional de nitrogênio do tomateiro.
The obj ective of the experiments was to determine nitrogen (SPAD value, petiole sap N-NO3 and organic N in the leaf above the first cluster dry matter) and crop growth indices (plant height, stem diameter, area and weight of the leaf adjacent to the first cluster) at the beginning of the tomato plant reproductive phase, in soil and nutrient solution. 'lhe experiments were arranged in a randomized complete black design with four replications. In the first experiment, tomato plant was grown in soil, in 3 L pot, with five N rates (O, lOO, 200, 400 and 800 Ing/dmª). In the second one, tomato plant was grown in nutrient solution at N rates of O,ª 4, 8, 12 and 16“ mínol/L, being 80% as N-NO3. At the beginning of the tomato plant reproductive phase, 37 and42 days alter transplantation time, the experiments in nutrient solution and soil were finished, respectively. At those times, plant height, stem diameter, area and weight of the leaf above the first cluster (LAC ), SPAD value and petiole sap N-No3 were evaluated. The plant was then harvested, separated in leaves and stem, dried, ground and weighed. Organic nitrogen contents were detennined in LAC dry matter. Nitrogen (NI) and crºp growth indices (CI) associated to 999% of the maximum tomato shoot dry matter, at both substrato, were presented. CI values were higher in plants grown in nutrient solution than in soil; the inverse was observed for NI but not for organic-N. It is proposed that plant height be utilized to predict shoot dry weight and it is also proposed that both FAC dry matter weight and are:: can be utilized to estimate tomato nitrogen nutritional status.
The obj ective of the experiments was to determine nitrogen (SPAD value, petiole sap N-NO3 and organic N in the leaf above the first cluster dry matter) and crop growth indices (plant height, stem diameter, area and weight of the leaf adjacent to the first cluster) at the beginning of the tomato plant reproductive phase, in soil and nutrient solution. 'lhe experiments were arranged in a randomized complete black design with four replications. In the first experiment, tomato plant was grown in soil, in 3 L pot, with five N rates (O, lOO, 200, 400 and 800 Ing/dmª). In the second one, tomato plant was grown in nutrient solution at N rates of O,ª 4, 8, 12 and 16“ mínol/L, being 80% as N-NO3. At the beginning of the tomato plant reproductive phase, 37 and42 days alter transplantation time, the experiments in nutrient solution and soil were finished, respectively. At those times, plant height, stem diameter, area and weight of the leaf above the first cluster (LAC ), SPAD value and petiole sap N-No3 were evaluated. The plant was then harvested, separated in leaves and stem, dried, ground and weighed. Organic nitrogen contents were detennined in LAC dry matter. Nitrogen (NI) and crºp growth indices (CI) associated to 999% of the maximum tomato shoot dry matter, at both substrato, were presented. CI values were higher in plants grown in nutrient solution than in soil; the inverse was observed for NI but not for organic-N. It is proposed that plant height be utilized to predict shoot dry weight and it is also proposed that both FAC dry matter weight and are:: can be utilized to estimate tomato nitrogen nutritional status.
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Palavras-chave
Lycopersicon esculenmm, Tomate, Análise foliar, SPAD, Diagnóstico, Nitrato na seiva do pecíolo