Exploratory analysis of nutrient concentrations in Eucalyptus leaf color patterns

The aim of this study was to evaluate the use of leaf color pattern to analyze leaf nutrient concentrations in Eucalyptus and to establish relationships between color patterns and leaf nutrient concentrations. The study was carried out in Eucalyptus stands at 25 months old using three leaves from the lower of tree crowns classified into five color patterns of Munsell color charts for plant tissues. The principal component analyses and the self-organizing maps were used to aid in the classification of samples in leaf color patterns. Subsequently, the k-means cluster algorithm was performed. In principal component analysis, the 7.5 GY 8/8 leaf color pattern stood out from the others and it was mainly influenced by nitrogen, phosphorous, copper, and potassium concentrations. The samples of 7.5 GY 8/4 leaf color pattern did not present a great nitrogen, phosphorous, sulfur, copper and potassium concentrations as the 7.5 GY 8/8 neither a great manganese, calcium, boron, zinc and iron concentrations as others leaf color patterns. The self-organizing map provides a greater proximity between the 7.5 GY 8/8 and 7.5 GY 8/4 leaf color patterns and the others leaf color patterns were randomly distributed in the U-matrix. Although the k-means algorithm presented two clusters in both analyses, the self-organizing map presented a slight superiority than principal component analysis. Using leaf color patterns was possible to infer about leaf nutrient concentrations in Eucalyptus. Both methods were able to distinguish only the healthy leaves 7.5 GY 8/8 from those whose were in the leaf senescence process

PADRÕES DE REFLECTÂNCIA FOLIAR DE EUCALIPTO EM DIFERENTES DIAS E PERÍODOS DO DIA

Faced with the complex relationship between leaf reflectance and physiological aspects of the plant on days and at different times of the day, the research was developed to ascertain and measure the influence of day and period of the day on leaf reflectance of eucalyptus trees. The experiment was carried out in a clonal eucalyptus stand, spontaneous Eucalyptus grandis hybrid with centroid at 18º 12 '12,19'S and 43º 34' 20,28''W. In each of the five sample trees randomly selected, four leaves were sampled at each cardinal point. All selected leaves were evaluated on days 7, 8, 9 and 10 of December 2013, in two periods of the day: between 8 and 9 hours and between 15 and 16 hours. The leaf reflectance was measured using a mini-spectrometer with subsequent smoothing and the analysis of principal components and subsequent analysis of dendrogram cluster were performed. In general, the average leaf reflectance on the second day was the lowest and the third day average was higher. Leaf reflectance was lower in the morning than in the afternoon. The day and period of the day of reading were randomly influenced by eucalypt leaf reflectance. The leaf reflectance of eucalyptus can change in a short time, even in the same day, which indicates the importance of the standardization in the collection schedule for future studies.Diante da complexa relação entre reflectância foliar e aspectos fisiológicos da planta em dias e diferentes horários do dia, a pesquisa foi desenvolvida para averiguar e mensurar o grau da influência do dia e o período do dia em espectros de reflectância foliar de árvores de eucalipto. O experimento foi conduzido em um plantio de eucalipto clonal, híbrido espontâneo de Eucalyptus grandis com centroide nas coordenadas 18º 12’ 12,19’’S e 43º 34’ 20,28’’O. Em cada uma das cinco árvores-amostra escolhidas aleatoriamente, amostraram-se quatro folhas distribuídas em cada ponto cardeal. Todas as folhas selecionadas foram avaliadas nos dias 7, 8, 9 e 10 de dezembro de 2013, em dois períodos do dia: entre 8 e 9 horas e entre 15 e 16 horas. A leitura da reflectância foliar foi realizada utilizando um mini-espectrometro com posterior suavização e dessa forma realizou-se a análise de componentes principais e com posterior análise de agrupamento por dendrograma. No geral, a média das reflectâncias foliares no segundo dia foram as menores e as médias do terceiro dia maiores. Em média a reflectância foliar foi menor no período da manhã do que no período da tarde. O dia e o período do dia em que foi realizada a leitura influenciaram de forma aleatória na reflectância foliar de eucalipto. A reflectância foliar do eucalipto pode se alterar em um curto período de tempo, inclusive em um mesmo dia, o que indica a importância da padronização no horário de coleta para futuros estudos

Physiological parameters in seedlings of copaiba under different shade conditions and substrates

O presente trabalho teve como objetivo avaliar par?metros fisiol?gicos de mudas de copa?ba produzidas sob o efeito de diferentes n?veis de sombreamento e tipos de substratos. O experimento teve a dura??o de 130 dias e foi conduzido em blocos casualizados no esquema fatorial 5x4, com cinco substratos: Bioplant?; 70% vermiculita + 30% casca de arroz carbonizada; 40% vermiculita + 30% casca de arroz carbonizada + 30% fibra de coco; 50% vermiculita + 30% casca de arroz carbonizada + 20% areia; 70% vermiculita + 15% casca de arroz carbonizada + 15% vermicomposto de res?duo de ind?stria t?xtil; quatro n?veis de sombreamento (100, 70, 50 e 30% do pleno sol) e tr?s repeti??es. O n?vel de sombreamento de 50% em rela??o ao pleno sol possibilitou a produ??o de mudas de copa?ba com maiores teores de clorofila b e clorofila total, al?m de proporcionar os menores valores de transpira??o di?ria e ao longo do dia das plantas. A ?rea foliar, os teores de clorofila e a transpira??o das mudas de copa?ba independem do tipo de substrato, podendo ser produzidas em qualquer um dos meios de crescimento avaliados.Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Empresa de Pesquisa Agropecu?ria de Minas Gerais (EPAMIG)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)This research aimed to evaluate physiological parameters of seedlings of copaiba produced under the effect of different shading levels and types of substrates. The experiment lasted 130 days and was conducted in randomized blocks in factorial scheme 5x4 with five substrates: Bioplant?, 70% vermiculite + 30% rice hulls, 40% vermiculite + 30% rice charred hulls + 30% fiber coconut, 50% vermiculite + 30% rice charred hulls + 20% sand, 70% vermiculite + 15% rice charred hulls + 15% vermicompost residue of textile industry; four shading levels (100, 70, 50 and 30% full sun) and three replications. The shade level of 50% compared to full sun, enabled the production of seedlings of Copaiba with higher concentrations of chlorophyll b and total chlorophyll, and provided the lowest daily transpiration throughout the day and the plants. The leaf area, chlorophyll content and transpiration of seedlings of Copaiba independent of the substrate and can be produced in any of the growth media evaluated

Estimating foliar nitrogen in Eucalyptus using vegetation indexes

Nitrogen (N) has commonly been applied in Eucalyptus stands in Brazil and it has a direct relation with biomass production and chlorophyll content. Foliar N concentrations are used to diagnose soil and plant fertility levels and to develop N fertilizer application rates. Normally, foliar N is obtained using destructive methods, but indirect analyses using Vegetation Indexes (VIs) may be possible. The aim of this work was to evaluate VIs to estimate foliar N concentration in three Eucalyptus clones. Lower crown leaves of three clonal Eucalyptus plantations (25 months old) were classified into five color patterns using the Munsell Plant Tissue Color Chart. For each color, N concentration was determined by the Kjeldahl method and foliar reflectance was measured using a CI-710 Miniature Leaf Spectrometer. Foliar reflectance data were used to obtain the VIs and the VIs were used to estimate N concentrations. In the visible region, the relationship between N concentration and reflectance percentage was negative. The highest correlations between VIs and N concentrations were obtained by the Inflection Point Position (IPP, r = 0.97), Normalized Difference Red-Edge (reNDVI, r = 0.97) and Modified Red-Edge Normalized Difference Vegetation Index (mNDI, r = 0.97). Vegetation indexes on the red edge region provided the most accurate estimates of foliar N concentration. The reNDVI index provided the best N concentration estimates in leaves of different colors of Eucalyptus urophylla × grandis and Eucalyptus urophylla × urophylla (R2 = 0.97 and RMSE = 0.91 g kg−1)

Ecophysiology modeling by artificial neural networks for different spacings in eucalypt

Growth and production models are widely used to predict yields and support forestry decisions. Artificial Neural Networks (ANN) are computational models that simulate the brain and nervous system human functions, with a memory capable of establishing mathematical relationships between independent variables to estimate the dependent variables. This work aimed to evaluate the efficiency of eucalypt biomass modeling under different spacings using Multilayer Perceptron networks, trained through the backpropagation algorithm. The experiment was installed in randomized block, and the effect of five planting spacings was studied in three blocks: T1 – 3.0 x 0.5 m; T2 – 3.0 x 1.0 m; T3 – 3.0 x 1.5 m; T4 – 3.0 x 2.0 m e T5 – 3.0 x 3.0 m. A continuous forest inventory was carried out at the ages of 48, 61, 73, 85 and 101 months. The leaf area, leaf perimeter and specific leaf area were measured at 101 months in one sample tree per experimental unit. Two thousand ANN were trained, using all inventoried trees, to estimate the eco-physiological attributes and the prognosis of the wood biomass. The artificial neural networks modeling was adequate to estimate eucalypt wood biomass, according to age and under different spacings, using the diameter-at-breast-height and leaf perimeter as predictor variables.Growth and production models are widely used to predict yields and support forestry decisions. Artificial Neural Networks (ANN) are computational models that simulate the brain and nervous system human functions, with a memory capable of establishing mathematical relationships between independent variables to estimate the dependent variables. This work aimed to evaluate the efficiency of eucalypt biomass modeling under different spacings using Multilayer Perceptron networks, trained through the backpropagation algorithm. The experiment was installed in randomized block, and the effect of five planting spacings was studied in three blocks: T1 – 3.0 x 0.5 m; T2 – 3.0 x 1.0 m; T3 – 3.0 x 1.5 m; T4 – 3.0 x 2.0 m e T5 – 3.0 x 3.0 m. A continuous forest inventory was carried out at the ages of 48, 61, 73, 85 and 101 months. The leaf area, leaf perimeter and specific leaf area were measured at 101 months in one sample tree per experimental unit. Two thousand ANN were trained, using all inventoried trees, to estimate the eco-physiological attributes and the prognosis of the wood biomass. The artificial neural networks modeling was adequate to estimate eucalypt wood biomass, according to age and under different spacings, using the diameter-at-breast-height and leaf perimeter as predictor variables

Artificial Neural Networks to Estimate Nutrient Use Efficiency in Eucalypt

Background: Nutrient use efficiency (NUE) is the basis for fertilizer recommendations in eucalypt plantations in Brazil needs to be calculate individually for each nutrient and spacing. The possibility of superior performance to conventional models of regression and interpolation can be obtained by Artificial Neural Networks (ANN) enabling its use for solve complex problems. The ANN are being used in environmental science, but still studies on forest nutrition are poor. Objective: To evaluate the efficiency of NUE estimation in the Eucalyptus stem, under different spacing using ANN. Results: The nonlinear activation functions in the hidden layer generating local receptive fields were observed in all networks. Specific leaf area contributed to capture the biological realism and increased the ability of generalization of MLP's networks. Its generalization capability and connectivity allowed use only one network to perform the estimation of the stem's NUE.Conclusion: The modeling by ANN using multilayer perceptron architecture is a suitable alternative, accurate and biologically realistic to estimate the NUE by macronutrient, used in different spacings

Climatic suitability for Eucalyptus cloeziana cultivation in four Brazilian states

The objective of this work was to identify zones with climatic potential for Eucalyptus cloeziana cultivation in four Brazilian states (Bahia – BA, Mato Grosso do Sul – MS, Minas Gerais – MG e São Paulo – SP). 490 records of this species in Australia were obtained. Current prediction of the distribution of habitat suitability was based on climatic conditions recorded between 1960 and 1990. For the future projections of 2050, four scenarios were used: RCP 2.6 W/m2, RCP 4.5 W/m2, RCP 6.0 W/m2 and RCP 8.5 W/m2. MaxEnt was used in modeling, and only climatic information was used as predictor variables. The modeling was robust and presented high values of AUC (> 0.95). Annual precipitation and isothermal were the variables that contributed the most for the quality of the models. It was concluded that the Brazilian mesoregions of Itapetininga (SP), Litoral Sul Paulista (SP) and Zona da Mata (MG) presented the most climatically suitable sites for E. cloeziana cultivation. Climatic changes may restrict the distribution of suitable zones for E. cloeziana cultivation. The negative effect of global warming was more prominent in MG

Quality of copaiba seedlings produced in two volumes of substrates and shading levels.

AbstractThis research aimed to evaluate the influence of two volumes of substrate and levels of shading on seedling quality of copaiba. The experiment was conducted for 130 days in a randomized block design in a 2 x 5 factorial scheme, we evaluated two volumes (180 e 280 cm³) of the five following substrates: Bioplant®, 70% vermiculite + 30% carbonized rice hulls, 40% vermiculite + 30% carbonized rice hulls + 30% coir, 50% vermiculite + 30% carbonized rice hulls + 20% sand and 70% vermiculite + 15% carbonized rice hulls + 15% vermicompost residue textiles. These ten combinations were randomly distributed in four blocks, accordingly to the following distinct brightness: 0, 30, 50 and 70 percentages of shading. The use of 180 cm³ substrate was enough to produce seedlings of copaiba with good development and quality index. The substrates 70V+30CA, 40V+30CA+30FC, 50V+30CA+20A, and 70V+15CA+15VC showed slight superiority over Bioplant® for seedlings of such species. The results revealed that the copaiba seedlings behaved differently in relation to shading levels evaluated, it demonstrates they have great adaptive plasticity.O presente trabalho teve como objetivo avaliar a influência de dois volumes de diferentes substratos e níveis de sombreamento sobre a qualidade de mudas de copaíba. O experimento foi conduzido por 130 dias em DBC casualizados no esquema fatorial 2 x 5, sendo avaliados dois volumes (180 e 280 cm³) dos substratos Bioplant®; 70% vermiculita + 30% casca de arroz carbonizada; 40% vermiculita + 30% casca de arroz carbonizada + 30% fibra de côco; 50% vermiculita + 30% casca de arroz carbonizada + 20% areia; e 70% vermiculita + 15% casca de arroz carbonizada + 15% vermicomposto. Essas dez combinações foram distribuídas aleatoriamente em quatro blocos com diferentes intensidades luminosas: 0, 30, 50 e 70% de sombreamento. O uso de 180 cm³ de substrato foi suficiente para produzir mudas de copaíba com bom desenvolvimento e índice de qualidade. Os substratos 70V+30CA, 40V+30CA+30FC, 50V+30CA+20A, 70V+15CA+15VC apresentaram-se superiores em relação ao Bioplant® para produção de mudas da espécie em estudo. Os resultados demonstraram que as mudas de copaíba comportaram-se de forma distinta em relação aos níveis de sombreamento avaliados, demonstrando possuírem grande plasticidade adaptativa.AbstractQuality of copaiba seedlings produced in two volumes of substrates and shading levels. This research aimed to evaluate the influence of two volumes of substrate and levels of shading on seedling quality of copaiba. The experiment was conducted for 130 days in a randomized block design in a 2 x 5 factorial scheme, we evaluated two volumes (180 e 280 cm³) of the five following substrates: Bioplant®, 70% vermiculite + 30% carbonized rice hulls, 40% vermiculite + 30% carbonized rice hulls + 30% coir, 50% vermiculite + 30% carbonized rice hulls + 20% sand and 70% vermiculite + 15% carbonized rice hulls + 15% vermicompost residue textiles. These ten combinations were randomly distributed in four blocks, accordingly to the following distinct brightness: 0, 30, 50 and 70 percentages of shading. The use of 180 cm³ substrate was enough to produce seedlings of copaiba with good development and quality index. The substrates 70V+30CA, 40V+30CA+30FC, 50V+30CA+20A, and 70V+15CA+15VC showed slight superiority over Bioplant® for seedlings of such species. The results revealed that the copaiba seedlings behaved differently in relation to shading levels evaluated, it demonstrates they have great adaptive plasticity.Keywords: Copaifera langsdorffii; production of seedlings; levels of brightness; containers

SAMPLING OF CHEMICAL ATTRIBUTES IN FOREST SOILS

Information about sample adequacy that represents soil chemical attributes distribution are fundamental for a better rationalization of the use of correctives and fertilizers. The objective was to evaluate the variability of these attributes and to size the minimum number of composite samples to represent the fertility of forest soils. The total area planted was 9,101ha, constituted of 265 commercial eucalypt stands. The 687 soil composite samples obtained were for chemical analysis. It was evaluated the performance of two exploratory analysis techniques and six sampling procedures. The attributes P, K, Ca, Mg and S presented higher coefficient of variation (>35%). In contrast, the distributions of Al, organic matter and, mainly, pH were the most homogeneous. The sample error was smaller as the amount of composite samples increased. The representative of all chemical attributes (sample error of 5%) was achieved with a minimum of 309 (one each 29ha, 1:29) and 295 (1:31) composite samples from sampling procedures simple casual and stratified by altitude class, respectively. Both procedures were promising for soil sampling, especially, when applying the boxplot for identification and removal of outliers