Biometric and morphological adjustments of Eugenia. dysenterica DC. seedlings in response to increased soil water deficit

Water stress can affect all aspects of plant growth and development, compromising its productive potential. The cultivation of fruit species native to the Cerrado and the study of their behavior under conditions of low water availability are necessary activities, in view of their socioeconomic and environmental potential. This study was conducted to evaluate the effect of water deficit on growth and biomass production of the cagaita tree (Eugenia dysenterica DC.), a species endemic to the Cerrado (Brazilian Savannah). The experiment was performed in a greenhouse for 120 days in a randomized block design (RBD), with a double factorial arrangement (2x5), corresponding to two cagaita mother plants and five water conditions. We evaluated the growth and leaf, stem and root functional characteristics. The most severe water deficit conditions reduced shoot growth, number of leaves, production of biomass and dry matter and increased the specific and per plant mass root length of cagaita plants. Deficit extension had negative effects on its growth and development. There was a statistical difference between mother plants, with mother plant 2 being more resistant to drought. The application of a severe or longer water deficit affected shoot growth and reduced the appearance of new leaves. The stress caused by water deficiency allowed an increase in root functional characteristics, supporting the hypothesis that plants under adverse conditions focus on higher biomass production and convert a higher amount of dry matter into the roots. Leaf area did not show to be a functional characteristic, explaining the stress effects in E. dysenterica DC plants.(AU)

Nonlinear models for soil moisture sensor calibration in tropical mountainous soils

Electromagnetic sensors are widely used to monitor soil water content (θ); however, site-specific calibrations are necessary for accurate measurements. This study compares regression models used for calibration of soil moisture sensors and investigates the relation between soil attributes and the adjusted parameters of the specific calibration equations. Undisturbed soil samples were collected in the A and B horizons of two Ultisols and two Inceptisols from the Mantiqueira Range in Southeastern Brazil. After saturation, the Theta Probe ML2X was used to obtain the soil dielectric constant (ε). Several readings were made, ranging from saturation to oven-dry. After each reading, the samples were weighted to calculate θ (m³ m-³). Fourteen regression models (linear, linearized, and nonlinear) were adjusted to the calibration data and checked for their residue distribution. Only the exponential model with three parameters met the regression assumptions regarding residue distribution. The stepwise regression was used to obtain multiple linear equations to estimate the adjusted parameters of the calibration model from soil attributes, with silt and clay contents providing the best relations. Both the specific and the general calibrations performed well, with RMSE values of 0.02 and 0.03 m³ m-³, respectively. Manufacturer calibration and equations from the literature were much less accurate, reinforcing the need to develop specific calibrations.

Aggregates morphometry of a Inceptisol under conservationist system / Morfometria de agregados de um Cambissolo sob manejo conservacionista

Morphological characteristics of the soil aggregates are important tools to analyzing and monitoring the structural quality. The present study aimed to characterize morphometrically aggregates of a Inceptisol, originated from pelitic rocks, after 1.5 years of the implementation of a management system that adopts conservation tillage practices in the coffee cultivation. The aggregates were collected at the depths of 0.0-0.05; 0.05-0.20; 0.20-0.40; 0.40-0.80 m, both at row and interrow position in a coffee field, and also a natural environment of native vegetation that was used as a reference for the study. The analyzes of the aggregates were carried through 2D images obtained by scanning at 300 dpi spatial resolution. Each image contained 60 households and were processed using the software QUANTPORO. The morphometric variables were obtained: area, perimeter, compactness, roughness, appearance and Ferret diameter. For validation, the correlations among morphometric variables determined by image analysis and pattern aggregation indices (GMD, MWD and aggregates retained in the class > 2.00 mm) obtained by wet sieving were studied. After 1.5 years of implantation increased the dimensions of the aggregates on the natural environment have been detected, as well as better structural quality Inceptisol.(AU)

As características morfológicas dos agregados são importantes indicadores da qualidade estrutural do solo. O presente trabalho teve por objetivo caracterizar morfometricamente os agregados de um Cambissolo originado de rochas pelíticas (siltito) após 1,5 anos da implantação de um sistema de manejo que adota práticas conservacionistas do solo no cultivo do cafeeiro. Os agregados foram coletados nas profundidades de 0,0-0,05; 0,05-0,20; 0,20-0,40; 0,40-0,80 m, nas posições linha e entrelinha do cafeeiro e também em um ambiente natural Cerrado Nativo tomado como referência para o estudo. As análises dos agregados foram realizadas por meio de imagens 2D obtidas por escaneamento, em 300 dpi de resolução espacial. Cada imagem continha 60 agregados e foram processadas utilizando o software Quantporo. As variáveis morfométricas obtidas foram: área, perímetro, compacidade, rugosidade, aspecto e diâmetro de Ferret. Para validação, foram estudadas as correlações entre as variáveis morfométricas determinadas pela análise de imagem e dos índices de agregação padrão (DMG, DMP e agregados retidos na classe > 2,00 mm) obtidos por tamisamento úmido. Após 1,5 anos de implantação do sistema de manejo foram detectados aumento nas dimensões dos agregados em relação ao ambiente natural, assim como melhor qualidade estrutural do Cambissolo.(AU)

Aggregates morphometry of a Inceptisol under conservationist system / Morfometria de agregados de um Cambissolo sob manejo conservacionista

Morphological characteristics of the soil aggregates are important tools to analyzing and monitoring the structural quality. The present study aimed to characterize morphometrically aggregates of a Inceptisol, originated from pelitic rocks, after 1.5 years of the implementation of a management system that adopts conservation tillage practices in the coffee cultivation. The aggregates were collected at the depths of 0.0-0.05; 0.05-0.20; 0.20-0.40; 0.40-0.80 m, both at row and interrow position in a coffee field, and also a natural environment of native vegetation that was used as a reference for the study. The analyzes of the aggregates were carried through 2D images obtained by scanning at 300 dpi spatial resolution. Each image contained 60 households and were processed using the software QUANTPORO. The morphometric variables were obtained: area, perimeter, compactness, roughness, appearance and Ferret diameter. For validation, the correlations among morphometric variables determined by image analysis and pattern aggregation indices (GMD, MWD and aggregates retained in the class > 2.00 mm) obtained by wet sieving were studied. After 1.5 years of implantation increased the dimensions of the aggregates on the natural environment have been detected, as well as better structural quality Inceptisol.

As características morfológicas dos agregados são importantes indicadores da qualidade estrutural do solo. O presente trabalho teve por objetivo caracterizar morfometricamente os agregados de um Cambissolo originado de rochas pelíticas (siltito) após 1,5 anos da implantação de um sistema de manejo que adota práticas conservacionistas do solo no cultivo do cafeeiro. Os agregados foram coletados nas profundidades de 0,0-0,05; 0,05-0,20; 0,20-0,40; 0,40-0,80 m, nas posições linha e entrelinha do cafeeiro e também em um ambiente natural Cerrado Nativo tomado como referência para o estudo. As análises dos agregados foram realizadas por meio de imagens 2D obtidas por escaneamento, em 300 dpi de resolução espacial. Cada imagem continha 60 agregados e foram processadas utilizando o software Quantporo. As variáveis morfométricas obtidas foram: área, perímetro, compacidade, rugosidade, aspecto e diâmetro de Ferret. Para validação, foram estudadas as correlações entre as variáveis morfométricas determinadas pela análise de imagem e dos índices de agregação padrão (DMG, DMP e agregados retidos na classe > 2,00 mm) obtidos por tamisamento úmido. Após 1,5 anos de implantação do sistema de manejo foram detectados aumento nas dimensões dos agregados em relação ao ambiente natural, assim como melhor qualidade estrutural do Cambissolo.

Potential use of zeolites in attenuation water deficit in cerrado latosol / Potencialidade de uso de zeólitas na atenuação do déficit hídrico em latossolo do cerrado

The improvements of hydro-physical conditions of the Cerrado Biome soils are extremely important in the view point of agricultural limitations in seasons of poor rainfall distribution and drought period. Against this background, we emphasize the potential use zeolites as soil conditioners, because they are minerals that have large interconnected voids that give them a high degree of hydration with ease to retain and release water. This study aimed to characterize the water retention in dystroferric Red Latosol, as well as the mineral zeolite, beyond their mixtures in order to investigate about ability of this mineral increasing the water availability range of Latosol for plants. The completely randomized experiment consisted of treatments based on mixtures of zeolite:Latosol in the proportion 2,5: 97,5%; 5:95%; 10:90% and 20:80%, respectively. In order to determination of water retention curve was established the water content in the following potential matric: -1, -2, -4, -6, -10 kPa suction units and -33, -100 kPa in chambers Richards and -500 the -1500 kPa in thermocouple psychrometer WP4-T in soil samples. Was fitted the van Genuchten model by nonlinear regression procedures of software SWRC, to experimental data. The addition of zeolite promoted changes in pore intermediates distribution of Latosol, enhancing water release for plants.

O melhoramento das condições físico-hídricas dos solos do Bioma Cerrado é de extrema importânciahaja vista as limitações agrícolas em períodos de veranico, principalmente. Neste contexto, salienta-seo uso potencial das zeólitas como condicionadoras de solo por serem minerais que possuem grandesespaços vazios interconectados que lhes conferem alto grau de hidratação, com facilidade de reter e liberar água. O objetivo foi caracterizar a retenção de água de um Latossolo Vermelho distroférrico; do mineral zeólita, e de suas misturas, no intuito de investigar a capacidade do mineral em incrementar o intervalo de disponibilidade hídrica em Latossolo. O experimento com delineamento inteiramente casualisado consistiu de tratamentos a base de misturas de zeólita: Latossolo nas proporções de 2,5: 97,5%; 5:95%; 10:90% e 20:80%, respectivamente. Para determinação da curva de retenção de água foi determinado o conteúdo de água das amostras submetidas aos potenciais matriciais: -1, -2, -4, -6, -10 kPa em unidades de sucção e -33, -100 kPa em câmaras de Richards e para potenciais de -500 a -1500 kPa no psicrômetro de termopar WP4-T. Foi ajustado o modelo de van Genuchten por meio de procedimentos de ajuste de modelos não lineares do software SWRC, aos dados experimentais. A adiçãode zeólita promoveu alterações na distribuição dos poros intermediários do Latossolo melhorando a liberação de água para as plantas.

Potential use of zeolites in attenuation water deficit in cerrado latosol / Potencialidade de uso de zeólitas na atenuação do déficit hídrico em latossolo do cerrado

The improvements of hydro-physical conditions of the Cerrado Biome soils are extremely important in the view point of agricultural limitations in seasons of poor rainfall distribution and drought period. Against this background, we emphasize the potential use zeolites as soil conditioners, because they are minerals that have large interconnected voids that give them a high degree of hydration with ease to retain and release water. This study aimed to characterize the water retention in dystroferric Red Latosol, as well as the mineral zeolite, beyond their mixtures in order to investigate about ability of this mineral increasing the water availability range of Latosol for plants. The completely randomized experiment consisted of treatments based on mixtures of zeolite:Latosol in the proportion 2,5: 97,5%; 5:95%; 10:90% and 20:80%, respectively. In order to determination of water retention curve was established the water content in the following potential matric: -1, -2, -4, -6, -10 kPa suction units and -33, -100 kPa in chambers Richards and -500 the -1500 kPa in thermocouple psychrometer WP4-T in soil samples. Was fitted the van Genuchten model by nonlinear regression procedures of software SWRC, to experimental data. The addition of zeolite promoted changes in pore intermediates distribution of Latosol, enhancing water release for plants.(AU)

O melhoramento das condições físico-hídricas dos solos do Bioma Cerrado é de extrema importânciahaja vista as limitações agrícolas em períodos de veranico, principalmente. Neste contexto, salienta-seo uso potencial das zeólitas como condicionadoras de solo por serem minerais que possuem grandesespaços vazios interconectados que lhes conferem alto grau de hidratação, com facilidade de reter e liberar água. O objetivo foi caracterizar a retenção de água de um Latossolo Vermelho distroférrico; do mineral zeólita, e de suas misturas, no intuito de investigar a capacidade do mineral em incrementar o intervalo de disponibilidade hídrica em Latossolo. O experimento com delineamento inteiramente casualisado consistiu de tratamentos a base de misturas de zeólita: Latossolo nas proporções de 2,5: 97,5%; 5:95%; 10:90% e 20:80%, respectivamente. Para determinação da curva de retenção de água foi determinado o conteúdo de água das amostras submetidas aos potenciais matriciais: -1, -2, -4, -6, -10 kPa em unidades de sucção e -33, -100 kPa em câmaras de Richards e para potenciais de -500 a -1500 kPa no psicrômetro de termopar WP4-T. Foi ajustado o modelo de van Genuchten por meio de procedimentos de ajuste de modelos não lineares do software SWRC, aos dados experimentais. A adiçãode zeólita promoveu alterações na distribuição dos poros intermediários do Latossolo melhorando a liberação de água para as plantas.(AU)