Abstract:RESUMO -Independentemente do índice de nitrogênio (N) utilizado, a existência de valores aceitos como concentração crítica é necessária para uso como padrão de referência. Objetivou-se estabelecer níveis críticos do índice SPAD, ângulo Hue, concentração de N-total e massa da matéria seca da quarta-folha da batateira por dois métodos e utilizar tais níveis críticos para a predição do estado de N da planta com base na produtividade relativa. Os experimentos foram conduzidos nas safras "de inverno" e "das águas".… Show more
“…The superior performance of CL in diagnosing true deficiency owes to the fact that it is obtained from experiments in which all environmental conditions were controlled, the gains or declines in yield being the result of adding the nutrient in those conditions [35]. The CL method is conventionally used to obtain reference values, albeit very restricted, since the tests are not repeated under different conditions [36].…”
The efficiency of methods in adequately interpreting the nutritional status of Eucalyptus spp. rooted cuttings remains unknown. The aim was to evaluate the quality of diagnoses obtained using the critical level (CL), diagnosis and recommendation integrated system (DRIS) and compositional nutrient diagnosis (CND) methods to assess the nutritional status of Eucalyptus spp. rooted cuttings, based on two different yield indicators. The data were obtained from commercial nursery and calibration experiments, using seven nutrients as treatments (N, P, K, Mg, Ca, B and Fe) and four concentrations per nutrient, arranged in randomized blocks, with four repetitions. The Eucalyptus spp. clone used in the experiments was AEC 0144. A total of 222 rooted cuttings were obtained from the experimental area and commercial nurseries and the following were determined: leaf nutrient content, whole plant dry matter (DM) content and the Dickson quality index (DQI). Diagnostic accuracy in the experimental plots was ascertained by comparing the diagnosis with plant response as a function of adding the corresponding nutrient. Five measures of accuracy were used to test the efficiency of the diagnostic methods: total accuracy, accuracy for deficiency and sufficiency, deficiency ratio, efficiency ratio, and the net increase in in DM and DQI. The performance of diagnostic methods varied between CL, DRIS and CND, and among the nutrients studied. Given that the seedling production system is largely more controlled, where environmental variations are minimal, and considering that the different diagnostic methods exhibited distinct performance in terms of assessing the true nutritional status of eucalyptus rooted cuttings, the CL method is the most indicated for this situation, due to its better performance in evaluating the nutritional status of most nutrients and easy implementation.
“…The superior performance of CL in diagnosing true deficiency owes to the fact that it is obtained from experiments in which all environmental conditions were controlled, the gains or declines in yield being the result of adding the nutrient in those conditions [35]. The CL method is conventionally used to obtain reference values, albeit very restricted, since the tests are not repeated under different conditions [36].…”
The efficiency of methods in adequately interpreting the nutritional status of Eucalyptus spp. rooted cuttings remains unknown. The aim was to evaluate the quality of diagnoses obtained using the critical level (CL), diagnosis and recommendation integrated system (DRIS) and compositional nutrient diagnosis (CND) methods to assess the nutritional status of Eucalyptus spp. rooted cuttings, based on two different yield indicators. The data were obtained from commercial nursery and calibration experiments, using seven nutrients as treatments (N, P, K, Mg, Ca, B and Fe) and four concentrations per nutrient, arranged in randomized blocks, with four repetitions. The Eucalyptus spp. clone used in the experiments was AEC 0144. A total of 222 rooted cuttings were obtained from the experimental area and commercial nurseries and the following were determined: leaf nutrient content, whole plant dry matter (DM) content and the Dickson quality index (DQI). Diagnostic accuracy in the experimental plots was ascertained by comparing the diagnosis with plant response as a function of adding the corresponding nutrient. Five measures of accuracy were used to test the efficiency of the diagnostic methods: total accuracy, accuracy for deficiency and sufficiency, deficiency ratio, efficiency ratio, and the net increase in in DM and DQI. The performance of diagnostic methods varied between CL, DRIS and CND, and among the nutrients studied. Given that the seedling production system is largely more controlled, where environmental variations are minimal, and considering that the different diagnostic methods exhibited distinct performance in terms of assessing the true nutritional status of eucalyptus rooted cuttings, the CL method is the most indicated for this situation, due to its better performance in evaluating the nutritional status of most nutrients and easy implementation.
“…The methods most used for interpretation of leaf analysis have been Critical Level (CL), Sufficiency Range (SR), Diagnosis and Recommendation Integrated System (DRIS), and Compositional Nutrient Diagnosis (CND) (Coelho et al, 2013;Gott et al, 2014). The CL method consists of mathematical models to establish the leaf nutrient contents that allow production of a certain fraction (90, 95, or 99 %) of maximum yield.…”
. The four diagnostic methods generated similar reference values of nutrients, but different from those found in the literature. Leaf diagnosis through nutrient content in the shoot at harvest time indicated Mn as the most limiting nutrient for growing carrot, followed by Mg, K, and Ca.
“…Desta forma, fica evidente a contribuição do solo no fornecimento de nitrogênio para a planta. No Brasil, alguns estados da região Sul e dos Cerrados tem utilizado o teor de matéria orgânica do solo como indicador para as recomendações das doses de nitrogênio, contudo ainda são necessárias outras avaliações para determinar a disponibilidade de nitrogênio para as culturas (COELHO et al, 2013).…”
Section: Avaliação De N No Solounclassified
“…A identificação de características e/ou indicadores referentes à cultura ou solo e que possam favorecer a recomendação de determinado nutriente, visando maior precisão e flexibilidade no manejo nitrogenado são de grande importância (COELHO et al, 2013). Para este experimento, na tentativa de encontrar algum atributo de solo que possa ser utilizado como preditor da resposta da cultura à adubação nitrogenada foram considerados os indicadores: ISNT, N mineral e N total nas camadas de 0-20 e 20-40 cm de profundidade e as medidas de eficiência de uso de nitrogênio.…”
Section: Relação Entre Atributos Químicos Do Solo E Eficiência De Usounclassified
Ao querido amigo Tiago A. Del Valle por toda atenção dispensada ao longo deste trabalho. E também pelas risadas e carinho. Os momentos passados juntos sempre serão lembrados com carinho! Aos produtores, universidades e laboratórios pelos espaços e pessoas cedidos para realização deste trabalho. Não citarei nomes aqui para não ser injusta.Aos colegas universitários, que foram indispensáveis para que esse projeto se realizasse: -UFSCar: Giovani Antonio (Bocati), Luana Santos Fernandes, Vitória Donadon (Coxinha), Luiz Paulo Veronese (Kotoco), Murilo Fila Gaio (Indigente), Lohanne Neomi Huber (Tala) e aos técnicos de laboratório João Luiz Consonni e Sílvia Raquel Bettani.-FZEA: Jéssica A. Bet, Gabriela Strozzi e aos técnicos Marcos Ferraz e Paulo Tonetti.-ESALQ: Thales M. S. Sattolo e Sarah Tenelli.Às amigas que dividiram o dia a dia pelo WhatsApp comigo. Vocês alegram demais os meus dias e me fizeram permanecer firme no propósito! Obrigada de coração por todas as mensagens, bons momentos e risadas! Aos amigos Getapistas que sempre estão presentes de alguma forma em tudo que faço.A todos que direta ou indiretamente contribuíram para a realização deste trabalho, e que por ventura, não intencionalmente tenham sido omitidos os devidos agradecimentos, minha sincera gratidão.
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