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1.
Semina ciênc. agrar ; 42(3,supl. 1): 1567-1578, 2021. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1501944

Resumo

The objective of this work was to evaluate the retention of P, K, Ca and Mg nutrients, as well as pH and electrical conductivity in Oxisols. Soil samples were placed into columns, with addition of humic substances (soil with and without liming). The experiment was conducted in a greenhouse and the columns consisted of PVC tubes with 40 cm height x 5 cm diameter. The humic substances used were humic acid and fulvic acid, applied at rates of 0, 60, 120 and 240 L ha-¹, in soil with or without lime. Ten irrigation events were performed, simulating 32 mm rainfall. After that, samples were collected from the columns, at 0-20 and 20-40 cm depths, to identify the residual effect of the addition of humic substances. A completely randomized design was used for this experiment, with 2×2×4 factorial statistical model and 3 replications. The results showed that, under acidic soil conditions, the use of fulvic acid provides more significant P release (up to 40%) in soil when compared to humic acid. When the rate of 240 L ha-¹ is applied, the fulvic acid can release up to 83% of P in the soil.


Neste trabalho avaliou-se a retenção dos nutrientes P, K, Ca e Mg, além do pH e condutividade elétrica em Latossolos, inseridos em colunas e adicionados de substâncias húmicas (na ausência e presença de calagem). O experimento foi conduzido em casa de vegetação e as colunas foram compostas por colunas de PVC de 40 cm de altura e 5 cm de diâmetro. As substâncias húmicas utilizadas foram o ácido húmico e o ácido fúlvico aplicados nas doses 0, 60, 120 e 240 L ha-¹ em solo com ou sem calcário. Dez eventos de irrigação foram realizados simulando chuvas de 32 mm. Em seguida, amostras das colunas foram coletadas nas profundidades de 0-20 e 20-40 cm para identificar o efeito residual da adição de substâncias húmicas. O experimento foi em delineamento inteiramente casualizado, com modelo estatístico fatorial 2×2×4 com 3 repetições. Os resultados mostraram que em condições de solo ácido, o uso do ácido fúlvico é mais expressivo na liberação de P (até 40% de liberação) no solo quando comparado ao ácido húmico. E, quando utilizada a taxa de 240 L ha-¹, o ácido fúlvico pode liberar até 83% de P no solo.


Assuntos
Análise do Solo , Cálcio/análise , Fósforo/análise , Magnésio/análise , Potássio/análise , Química do Solo , Umidade do Solo
2.
Semina Ci. agr. ; 42(3,supl. 1): 1567-1578, 2021. tab, graf
Artigo em Inglês | VETINDEX | ID: vti-765824

Resumo

The objective of this work was to evaluate the retention of P, K, Ca and Mg nutrients, as well as pH and electrical conductivity in Oxisols. Soil samples were placed into columns, with addition of humic substances (soil with and without liming). The experiment was conducted in a greenhouse and the columns consisted of PVC tubes with 40 cm height x 5 cm diameter. The humic substances used were humic acid and fulvic acid, applied at rates of 0, 60, 120 and 240 L ha-¹, in soil with or without lime. Ten irrigation events were performed, simulating 32 mm rainfall. After that, samples were collected from the columns, at 0-20 and 20-40 cm depths, to identify the residual effect of the addition of humic substances. A completely randomized design was used for this experiment, with 2×2×4 factorial statistical model and 3 replications. The results showed that, under acidic soil conditions, the use of fulvic acid provides more significant P release (up to 40%) in soil when compared to humic acid. When the rate of 240 L ha-¹ is applied, the fulvic acid can release up to 83% of P in the soil.(AU)


Neste trabalho avaliou-se a retenção dos nutrientes P, K, Ca e Mg, além do pH e condutividade elétrica em Latossolos, inseridos em colunas e adicionados de substâncias húmicas (na ausência e presença de calagem). O experimento foi conduzido em casa de vegetação e as colunas foram compostas por colunas de PVC de 40 cm de altura e 5 cm de diâmetro. As substâncias húmicas utilizadas foram o ácido húmico e o ácido fúlvico aplicados nas doses 0, 60, 120 e 240 L ha-¹ em solo com ou sem calcário. Dez eventos de irrigação foram realizados simulando chuvas de 32 mm. Em seguida, amostras das colunas foram coletadas nas profundidades de 0-20 e 20-40 cm para identificar o efeito residual da adição de substâncias húmicas. O experimento foi em delineamento inteiramente casualizado, com modelo estatístico fatorial 2×2×4 com 3 repetições. Os resultados mostraram que em condições de solo ácido, o uso do ácido fúlvico é mais expressivo na liberação de P (até 40% de liberação) no solo quando comparado ao ácido húmico. E, quando utilizada a taxa de 240 L ha-¹, o ácido fúlvico pode liberar até 83% de P no solo.(AU)


Assuntos
Análise do Solo , Química do Solo , Umidade do Solo , Fósforo/análise , Potássio/análise , Cálcio/análise , Magnésio/análise
3.
Ci. Rural ; 50(8): e20190606, July 10, 2020. tab, graf, ilus
Artigo em Inglês | VETINDEX | ID: vti-26811

Resumo

The construction of the hydroelectric power plant of Ilha Solteira, in state of São Paulo, was initiated in the 1960s, when an average, 8.60 m of soil depth was removed, resulting in a degraded area. A plan for the recovery of the area started in 2005 in Selvíria /MS with the use of plant species adapted to the Cerrado biome. This study aimed to evaluate the soil macrofauna of an area under recovery by using different types of soil cover (1- bare soil (control); 2- native Cerrado vegetation; 3- specie Astronium fraxinifolium; 4- Astronium fraxinifolium + Canavalia ensiformis; 5- Astronium fraxinifolium + Raphanus sativus; 6- Astronium fraxinifolium + Brachiaria decumbens + sewage sludge). Soil macrofauna was evaluated in 2005, 2006 and 2007 using the direct collection method and manual counting. Number of species, diversity and uniformity index were determined. Principal component analysis (PCA) and cluster analysis were used for data interpretation. Results showed that treatment 6 (Astronium fraxinifolium+ Brachiaria decumbens+ sewage sludge) increased the soil macrofauna population by approximately 4 to 6 times more than the other types of cover after three years of evaluation. And the PCA and cluster analysis showed the approximation of the data between treatment 6 and Cerrado, which represents the most appropriate treatment for the recovery of the degraded soil.(AU)


A construção da usina hidrelétrica de Ilha Solteira, no interior de São Paulo, foi iniciada nos anos 1960, quando foi retirado, em média, 8,60 m de solo em profundidade, dando origem a uma área degradada. Com isso, iniciou-se em 2005 um plano de recuperação da área no município de Selvíria/MS com plantio de espécies vegetais adaptadas ao bioma Cerrado. Assim, este trabalho teve como objetivo avaliar a macrofauna do solo de uma área em processo de recuperação com plantio de diferentes tipos de cobertura vegetal (1- solo nu (testemunha); 2- vegetação nativa de Cerrado; 3- espécie arbórea Astronium fraxinifolium; 4- Astronium fraxinifolium + Canavalia ensiformis; 5- Astronium fraxinifolium + Raphanus sativus; 6- Astronium fraxinifolium + Brachiaria decumbens + lodo de esgoto). A macrofauna de solo foi avaliada em 2005, 2006 e 2007 utilizando o método de coleta direta e contagem manual. Foram determinados: quantidade de espécies e índices de diversidade e uniformidade. As análises de componentes principals (PCA) e de cluster foram utilizadas para interpretação de dados. Os resultados mostraram que o tratamento 6 (Astronium fraxinifolium + Brachiaria decumbens + lodo de esgoto) aumentou a população de macrofauna do solo em aproximadamente 4 a 6 vezes mais que os demais tipos de cobertura vegetal após três anos de avaliação. As análises de PCA e de cluster mostraram aproximação dos dados do tratamento 6 às condições ambientais naturais de Cerrado, indicando ser o tratamento mais adequado para a recuperação do solo degradado.(AU)


Assuntos
Tratamento do Solo , Biomarcadores Ambientais , Pradaria
4.
Sci. agric. ; 75(4): 281-287, jul.-ago. 2018. tab, graf
Artigo em Inglês | VETINDEX | ID: vti-728767

Resumo

The Random Forest algorithm is a data mining technique used for classifying attributes in order of importance to explain the variation in an attribute-target, as soil CO2 flux. This study aimed to identify prediction of soil CO2 flux variables in management systems of sugarcane through the machine-learning algorithm called Random Forest. Two different management areas of sugarcane in the state of São Paulo, Brazil, were selected: burned and green. In each area, we assembled a sampling grid with 81 georeferenced points to assess soil CO2 flux through automated portable soil gas chamber with measuring spectroscopy in the infrared during the dry season of 2011 and the rainy season of 2012. In addition, we sampled the soil to evaluate physical, chemical, and microbiological attributes. For data interpretation, we used the Random Forest algorithm, based on the combination of predicted decision trees (machine learning algorithms) in which every tree depends on the values of a random vector sampled independently with the same distribution to all the trees of the forest. The results indicated that clay content in the soil was the most important attribute to explain the CO2 flux in the areas studied during the evaluated period. The use of the Random Forest algorithm originated a model with a good fit (R2 = 0.80) for predicted and observed values.(AU)


Assuntos
Saccharum , Dióxido de Carbono , Análise do Solo , Argila/análise , Mineração de Dados , 24444 , Estação Seca , Estação Chuvosa
5.
Sci. agric ; 73(6): 543-551, 2016. ilus, tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1497602

Resumo

The harvesting system of green sugarcane, characterized by mechanized harvesting and no crop burning, affects soil quality by increasing the remaining straw left on the soil surface after harvesting, thus, contributing to the improvement of physical, chemical, and microbiological soil attributes, influencing CO2 fluxes. This study aimed to evaluate CO2 fluxes and their relation to soil properties in sugarcane crops under different harvesting managements: burned (B), Green harvesting for 5 years (G-5) and Green harvesting for ten years (G-10). For this, a 1 ha sampling grid with 30 points was installed in each area, all located in the Northeast of São Paulo State, Brazil. In each point, CO2 fluxes were measured and the soil was sampled to analyze the microbial biomass, physical (soil moisture and temperature, mean weight diameter, bulk density, clay, macroporosity and microporosity) and chemical characterization (pH, organic C, base saturation and P). The CO2 fluxes were divided into four quantitative criteria: high, moderate, low and very low from the Statistical Division (mean, first quartile, median and third quartile) and the other data were classified according this criterion. The Principal Component Analysis (PCA) was used to identify the main soil attributes that influence CO2 fluxes. The results showed that G-10 CO2 fluxes were 28 and 41 % higher than those in the G-5 and B treatments, respectively. The PCA analysis showed that macroporosity was the main soil attribute that influenced the high CO2 fluxes.


Assuntos
Biologia do Solo , Características do Solo , 24444 , Dióxido de Carbono , Saccharum , Agricultura , Biomassa , Porosidade , Produtos Agrícolas , Qualidade do Solo
6.
Sci. agric. ; 73(6): 543-551, 2016. ilus, tab, graf
Artigo em Inglês | VETINDEX | ID: vti-684152

Resumo

The harvesting system of green sugarcane, characterized by mechanized harvesting and no crop burning, affects soil quality by increasing the remaining straw left on the soil surface after harvesting, thus, contributing to the improvement of physical, chemical, and microbiological soil attributes, influencing CO2 fluxes. This study aimed to evaluate CO2 fluxes and their relation to soil properties in sugarcane crops under different harvesting managements: burned (B), Green harvesting for 5 years (G-5) and Green harvesting for ten years (G-10). For this, a 1 ha sampling grid with 30 points was installed in each area, all located in the Northeast of São Paulo State, Brazil. In each point, CO2 fluxes were measured and the soil was sampled to analyze the microbial biomass, physical (soil moisture and temperature, mean weight diameter, bulk density, clay, macroporosity and microporosity) and chemical characterization (pH, organic C, base saturation and P). The CO2 fluxes were divided into four quantitative criteria: high, moderate, low and very low from the Statistical Division (mean, first quartile, median and third quartile) and the other data were classified according this criterion. The Principal Component Analysis (PCA) was used to identify the main soil attributes that influence CO2 fluxes. The results showed that G-10 CO2 fluxes were 28 and 41 % higher than those in the G-5 and B treatments, respectively. The PCA analysis showed that macroporosity was the main soil attribute that influenced the high CO2 fluxes.(AU)


Assuntos
Biologia do Solo , Características do Solo , Saccharum , Dióxido de Carbono , 24444 , Agricultura , Produtos Agrícolas , Porosidade , Biomassa , Qualidade do Solo
7.
Braz. J. Microbiol. ; 45(3): 963-969, July-Sept. 2014. tab
Artigo em Inglês | VETINDEX | ID: vti-28043

Resumo

Humic substances result from the degradation of biopolymers of organic residues in the soil due to microbial activity. The objective of this study was to evaluate the influence of three different ecosystems: forest, pasture and maize crop on the formation of soil humic substances relating to their biological and chemical attributes. Microbial biomass carbon (MBC), microbial respiratory activity, nitrification potential, total organic carbon, soluble carbon, humic and fulvic acid fractions and the rate and degree of humification were determined. Organic carbon and soluble carbon contents decreased in the order: forest > pasture > maize; humic and fulvic acids decreased in the order forest > pasture=maize. The MBC and respiratory activity were not influenced by the ecosystems; however, the nitrification potential was higher in the forest than in other soils. The rate and degree of humification were higher in maize soil indicating greater humification of organic matter in this system. All attributes studied decreased significantly with increasing soil depth, with the exception of the rate and degree of humification. Significant and positive correlations were found between humic and fulvic acids contents with MBC, microbial respiration and nitrification potential, suggesting the microbial influence on the differential formation of humic substances of the different ecosystems.


Assuntos
Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Substâncias Húmicas/análise , Microbiologia do Solo , Solo/química , Agricultura , Carbono/análise , Florestas
8.
Jaboticabal; s.n; 26/02/2010. 115 p.
Tese em Português | VETTESES | ID: vtt-3723

Resumo

A mineralização da matéria orgânica do solo pode ser compreendida como o processo de degradação de compostos orgânicos por resíduos de culturas e outros materiais orgânicos adicionados no solo. O efeito da mineralização em diferentes ecossistemas e tipos de solos é uma oportunidade para avaliar mudanças nas variáveis microbiológicas e químicas do solo. Nesse trabalho, foi avaliado o efeito da mineralização da matéria orgânica do solo em duas situações: experimento: (1) em diferentes ecossistemas e (2) - em dois solos adicionados de folha e caule de soja. Experimento 1- O objetivo desse trabalho foi quantificar a mineralização da matéria orgânica nos ecossistemas de floresta natural, pastagem e cultura anual na atividade microbiana do solo. As amostras de solo foram coletadas nas áreas de floresta, pastagem e cultura anual (milho), nas profundidades de 0 ?10, 10 ? 20 e 20 ? 40 cm. O carbono da biomassa microbiana (CBM), atividade respiratória microbiana (ARM) e o potencial de nitrificação (PN) foram determinados. Carbono orgânico total (COT), carbono solúvel (CS), ácido húmico (AH) e fúlvico (AF) e a taxa de humificação (TH) e grau de humificação (GH) também foram determinados. O modelo estatístico usado foi o de parcelas subdvididas (fator 1: ecossistemas e fator 2: profundidade) com quatro repetições. No inverno, os teores de COT e CS foram maiores no solo de floresta que no de pastagem e cultura anual de acordo com a ordem: floresta>pastagem>cultura anual e no verão prevaleceu floresta=pastagem>cultura anual. Os teores de AH e AF variaram no inverno e verão de acordo com a ordem floresta>pastagem=cultura anual. O CBM no inverno não foi influenciado pelos ecossistemas e no verão apenas o ecossistema com cultura anual apresentou menor teor de CBM. A ARM foi maior no solo sob pastagem que em solo de floresta e cultura anual, porém...


Soil organic matter mineralization can be understood as a process of degradation of organic compounds from crop residues and other organic material added into the soil. The effect of mineralization in different ecosystems and soil types is an opportunity to assess changes in microbiological and chemical variables of soil. The effect of soil organic matter mineralization was evaluated in two experiments: (1) in different ecosystems; and (2) - in two soils added with leaves and stems of soybean. Experiment 1 ? the objective of this study was to quantify the mineralization of organic matter from different ecosystems including natural forest, pasture and annual crop on soil microbial activity. Soil samples were collected from areas of forest, pasture and maize, at depths of 0 -10, 10 - 20 and 20 - 40 cm. The microbial biomass carbon (MBC) contents and the activities of microbial respiratory (MRA), potential nitrification (PN) were determined. Total organic carbon (TOC), dissoLVefd carbon (CS), humic acid (HA) and fulvic (FA) contents and humification rate (TH) and degree of humification (GH) were also determined. The statistical model used was a split plot (factor 1: ecosystem and factor 2: depth) with four replicates. In winter, the TOC and CS contents were higher in the forest soil than in the pasture and annual crop soil and decreased in the following order: forest> pasture> annual crop. in the summer, the relationship was the following: forest =pasture> annual crop. The HA and FA contents varied in winter and summer in the order forest>grassland=annual crop. The CBM content was not influenced by ecosystems in winter and in summer the lowest CBM amount was showed in annual crop. ARM was higher in pasture soil than in forest soil and annual crop, however, the NP was highest in forest soil. The chemical and biological attributes decreased with soil depth, except the rate and degree...

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