Jairo Rafael Machado Dias

Normas DRIS regionais e inter‑regionais na avaliação nutricional de café Conilon

The objective of this work was to evaluate the performance of regional and inter‑regional norms of the diagnosis and recommendation integrated system (DRIS) on the nutritional diagnosis of Conilon coffee (Coffea canephora). Data on foliar contents of N, P, K, Ca, and Mg, obtained from 268 coffee crops from the states of Espirito Santo and Rondonia, Brazil, were used to define four sets of DRIS norms: three for specific conditions (regional norms), and one for all the tested conditions (inter-regional norms). Crops differed greatly as to management and environmental conditions. After the determination of the norms, the nutritional diagnoses obtained from them were confronted with each other. All the norms were effective in providing diagnoses to distinguish the nutritional patterns of the crops, both in the states of Espirito Santo and Rondonia. For the inter‑regional DRIS norms, the means and standard deviations of the multivariate ratios between nutrients had intermediate values in comparison to those obtained for the sets of regional norms. No randomness was observed in the nutritional diagnosis provided by inter‑regional norms, which had a great agreement level with the one provided by regional norms. Specific norms should be used only in the conditions in which they were developed, whereas generic norms have a wider applicability without jeopardizing the accuracy of the diagnosis.

DRIS formulas for evaluation of nutritional status of cupuaçu trees

DRIS, an Diagnosis and Recommendation Integrated System, is a tool to evaluate the nutritional status of plants. Different DRIS formulas have been proposed to improve the efficiency of the crop nutrition diagnoses. The objective of this study was to compare the nutritional diagnosis of the formulas of Beaufils (1973), of Jones (1981) and of Elwali and Gascho (1984), based on the degree of agreement in commercial orchards of Theobrama grandiflorum trees. Leaf samples of 5 to 18 year-old cupuacu trees were collected from 153 commercial orchards in agroforestry and monoculture systems in the state of Rondonia, Brazil. Bivariate relationships between nutrition concentrations in healthy trees were used to calculate DRIS norms. DRIS indices were calculated based on the different formulas and interpreted by the Potential Fertilizer Response method, in five categories. The DRIS norms, DRIS index calculations and their interpretations were developed using the DRIS Cupuacu computer program (www.dris.com.br). The different DRIS formulas resulted in similar diagnoses with a degree of agreement of > 90% for the nutrients N, P, K, Ca, and Mg.

Interpretação de índices dris para a cultura do cupuaçu

A produtividade dos pomares de cupuacu na Amazonia tem experimentado lento declinio, provavelmente devido a diminuicao da fertilidade do solo, requerendo adubacoes. Na ausencia de recomendacoes tecnicas para quantificar a demanda por nutrientes por essa cultura, o uso do Sistema Integrado de Diagnose e Recomendacao (DRIS) pode representar uma alternativa para suprir essa necessidade. O objetivo deste trabalho foi avaliar os diagnosticos produzidos por diferentes formulas e criterios de interpretacao dos indices DRIS em pomares de cupuacu. Amostras foliares de 153 pomares foram analisadas para os nutrientes N, P, K, Ca, Mg, Zn, Mn, Cu e Fe e diagnosticadas por tres formulas DRIS: Beaufils, Jones e Wadt e colaboradores. Na interpretacao dos indices DRIS, utilizaram-se: o metodo DRIS Materia Seca (M-DRIS), que separa os nutrientes em limitantes ou nao limitantes, e o metodo do Potencial de Resposta a Adubacao, o qual separa os nutrientes no estado nutricional de insuficientes, equilibrados ou em excesso. Foram tambem adotados niveis criticos para os teores dos nutrientes foliares em cupuacueiros, oriundos da literatura. Os diagnosticos produzidos pelos diferentes criterios de interpretacao dos indices DRIS nao foram consistentes entre si ou em comparacao com o metodo do nivel critico. A excecao foi a formula de Wadt e colaboradores que mostrou maior consistencia entre os diagnosticos, independentemente do criterio utilizado para sua interpretacao. Os valores sugeridos para avaliacao do estado nutricional pelo metodo do nivel critico nao foram satisfatorios.

Avaliação nutricional de feijoeiro irrigado pelos métodos CND, DRIS e faixas de suficiência

The common bean crop is of great importance for the State of Goias, Brazil. However, information on its nutritional requirements is lacking for irrigated conditions. The aim of this study was to establish standard levels of leaf nutrients and assess the nutritional status of irrigated common bean in the Vale do Rio dos Bois region of the State of Goias through the methods of sufficiency range (SR), compositional nutrient diagnosis (CND), and diagnosis and recommendation integrated system (DRIS), as well as compare the diagnostic procedures through local nutritional standards. The yield and leaf nutrient concentration of 55 common bean crops were evaluated in the Vale do Rio dos Bois region from 2010 to 2012. Samples were collected at the R5 (flowering) stage and were analyzed for total N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn. The 55 samples were divided into two groups, the first being of low yield, below 2,700 kg ha-1, and the second of high yield, at or above 2,700 kg ha-1, the latter serving to define nutrient standards. CND and DRIS standards are more recommended for nutritional assessment of irrigated common bean compared to SR, as estimated in this study. Manganese, P, and B are the elements that most limit production in low yielding crops in the Vale do Rio dos Bois region.

Normas DRIS multivariadas para avaliação do estado nutricional de laranjeira ‘Pera’ no estado do Amazonas

In order to use nutritional-composition diagnosis or the diagnosis and integrated recommendation system of multivariate relationships (DRIS) when assessing the nutritional status of the orange, it becomes necessary to define reference values that are suitable for indicating nutritional conditions. This study aimed to establish multivariate DRIS standards, and to evaluate their comparative performance in assessing the nutritional status of the Pera orange in the state of Amazonas against nutritional standards as defined in the literature. We evaluated the nutritional status of 120 commercial plots of a hybrid of the Pera orange and Rangpur lime, the reference values being defined from the group of plots. DRIS standards for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) were established and nutritional diagnosis by DRIS, combined with the comparative use of generic standards to those proposed in the literature, showed a low level of agreement when assessing the nutritional status of the Pera orange in the state of Amazonas.

Potencial de resposta à adubação para N, P, K, Ca e Mg em cupuaçueiros avaliados por diferentes normas DRIS

The response of potential fertilization is a tool used to interpret the values of DRIS indices, so that it may be useful to see if different groups of rules might result in different or similar diagnosis among themselves. In this sense, it we aimed to evaluate the performance of the nutritional diagnosis, submitted to five groups of DRIS norms. For this, leaf samples were collected from commercial cupuacueiro orchards, whose plant ages ranged from 5 to 18, with cropping or agroforestry (SAF). For each relationship among the nutrition nutrients N, P, K, Ca and Mg, we obtained bivariate DRIS standards for all populations and monitored for specific subpopulations. The different standards resulted in DRIS diagnoses similar for N, P and Ca and distinct for Mg and K the produced diagnoses stood out among the norms resulting in nutritional deviations.

Milho consorciado com capim tifton na Amazônia sul ocidental

The objective of this work was to evaluate the performance of intercropped corn with tifton grass in South Western Amazonia. The experimental design was randomized blocks with six treatments and four replications. The treatments consisted of corn monocultures and tifton grass, and four transplantation periods of tifton between the corn sowing lines, as follows: simultaneously, at 15, 30 and 45 days after sowing corn. For corn, these were evaluated: biomass of 100 grains, number of kernel rows per ear, grain yield, plant height and insertion of the first spike. The dry biomass of tifton grass was estimated from two cuts with an interval of 20 days between the first and second collections. To evaluate the performance of intercrops compared to monocultures, we used the area equivalence ratio. The results were submitted to the Shapiro-Wilk test (p ≤ 0.05) in order to assess the normality of the data, followed by analysis of variance. Regression models were adjusted for the period of implantation of tifton grass between the corn sowing lines, when there was a significant effect by F test, at 5% probability. The Dunnet test was used (p ≤ 0.05) for the comparisons between the corn intercropped with tifton and monocultures (control). Corn is not affected when intercropping with tifton grass. However, tifton has a lower accumulation of dry biomass when intercropped with corn. The best performance of the consortium was the simultaneous implantation of corn with tifton grass.