Antonio Carlos Tadeu Vitorino

Avaliação do estado nutricional da soja

The objetive of of this work was to compare the diagnostics of the nutritional state of a group of 111 commercial soybean plantations, obtained by Diagnosis and Recommendation Integrated System (DRIS) and Compositional Nutrient Diagnosis (CND) methods applying the response potencial to fertilization concept. It was observed that zinc, phosphorus and iron were the nutrients diagnosed by both methods as the more restrictive for lack, and magnesium and manganese the more restrictive for excess. Agreement between DRIS and CND diagnoses was higher for nutrients considered of greater relative deficiency (90.3%) than for those considered of greater relative excess (81.9%). When the classes of nutritional state were evaluated, the frequency of plantations with concordant diagnosis varied from 85.9% for phosphorus to 98.6% for manganese. DRIS and CND methods tend to be consonants about nutritional status diagnoses; classes grouping of potential response to fertilization may result in grouping in one class of nutritional state nutrients with high and low probability of response.

Determinação de teores ótimos de nutrientes em soja pelos métodos chance matemática, sistema integrado de diagnose e recomendação e diagnose da composição nutricional

Several studies pointed out the promising use of nutritional diagnosis methods for the determination of optimum nutrient contents and critical levels in plant tissues. Thus, the objective of this study was to compare the optimum nutrient content for soybean, estimated by the Mathematical Chance (ChM), Diagnosis and Recommendation Integrated System (DRIS) and Compositional Nutrient Diagnosis (CND) methods. The optimum nutrient contents estimated by DRIS and CND where identical to the mean content in the reference population. Apart from the nutrients Cu, Fe, Mn and Zn, the optimum contents were also equal or in close proximity to the mean nutrient contents of the reference population by the ChM method. The ChM, DRIS and CND methods proved promising for the calibration of optimal nutrient contents for soybean based on data obtained from nutrient monitoring of commercial fields.

Intervalo hídrico ótimo em um latossolo vermelho distroférrico sob diferentes sistemas de produção

The objective of this work was to characterize the growing systems related to the structural soil quality for plants development by the Least Limiting Water Range (LLWR). The study was developed using soil samples with preserved structure of a Distroferric Red Latossol under the conventional, no tillage and integrated growing systems in de county of Dourados-MS, Brazil. In each system 28 points were sampled, in 0-0.05, 0.05-0.10 and 0.10-0.20 m deep layers, ending up with 84 samples by system which was used to adjust the water retention curve in the soil, soil resistance to penetration curve and porosity determination, all of them necessary to the LLWR determination. In the conventional and no-tillage systems the smallest restriction to de roots development was in the 0-0.05 m layer, while in the integration system the smallest limiting was in 0.10-0.20 m layer. In the conventional system, in the 0-0.05 m layer, the LLWR was equal to the available water capacity, in the direct and integrated systems the resistance to penetration was the limiting factor. The resistance to penetration was the major limiting factor in most of the studied situations.

Mineralogia, química e estabilidade de agregados do tamanho de silte de solos da Região Sudeste do Brasil

The objective of this work was to evaluate the relationship of soil mineralogical and chemical composition with stability of silt-size aggregates. The studies were carried out using samples of A and B horizons of some soils from the Southeast Region of Brazil. Fine-earth samples were dispersed at 12,000 rpm during 20 minutes and the silt fraction was separated through clay fraction drain, constituting the fraction named pseudo-silt, which was sonificated, separating the desegregated clay fraction (by sonication) from the properly named silt fraction. Correlation analyses showed that the soil mineralogical and chemical compositions have marked influence upon clay dispersion, with reflections on the silt fraction. Higher amounts of gibbsite reflect in higher stability of silt-size aggregates, while the kaolinite promotes inverse effect. The Al forms determined on the pseudo-silt fraction are associated with higher difficult of dispersion of clay fraction of soils.

INOCULAÇÃO DO FEIJOEIRO COM RHIZOBIUM TROPICI ASSOCIADA À EXSUDATO DE MIMOSA FLOCCULOSA COM DIFERENTES DOSES DE NITROGÊNIO

The aim of this work was to evaluate the effect of the Rhizobium inoculation, associated with seed exudates of Mimosa flocculosa, under different rates of nitrogen fertilization was evaluated in bean crops following soybean (Glycine max L. Merril) and corn (Zea mays L.). The experimental design was randomized blocks with four replications, with treatments arranged in sub-divided parcels. The parcels were constituted of two summer crops preceding the common bean crop: soybean and corn. In the sub-parcels three treatments involving inoculation of the common bean seeds were considered: control treatment without inoculation; bean seeds inoculated with Rhizobium tropici, strains CIAT 899 and PRF 81, and the association of Rhizobium with the exudates of the Mimosa flocculosa seeds. The sub-subparcels received of four doses of nitrogen fertilization applied on covering: 0, 40, 80 and 120 kg ha-1 N. The inoculation of Rhizobium associated with the addition of exudates of Mimosa flocculosa seeds resulted in higher shoot dry weight. Besides that, the nitrogen fertilization, on the tested doses, reduced, in a linear way, the nodulation of the bean plant. It was also verified that corn as a preceding crop for bean has contributed to the increase of the weight of 100 grains, while the addition of combined N did not contribute to the improvement on the number of beans per plant, neither of the grain yield of bean plants, independent of the dose that was used.

Campos nativos e matas adjacentes da região de Humaitá (AM): atributos diferenciais dos solos

Existem no sul do Amazonas aproximadamente 560 mil hectares de campos de cerrados, distribuidos principalmente, nos municipios de Humaita, Labrea e Canutama. A regiao nao e coberta por campos continuos, mas por varias unidades isoladas entremeadas por matas. As formas de vegetacao primitiva indicam ambientes peculiares, como o regime hidrico, fertilidade natural e aeracao do solo. Assim, objetivou-se no presente trabalho estabelecer algumas razoes da estratificacao ambiental entre mata e campo nativo na regiao de Humaita (AM). Para tanto, foram observados morfologicamente e amostrados 10 perfis de solos, sendo 5 perfis sob mata e 5 perfis sob campo cerrado nativo. As amostras foram coletadas nas profundidades de 0-20, 20-40 e 60-80 cm, em trincheiras. Os solos sob vegetacao de campo nativo e sob mata possuem atributos quimicos semelhantes e mineralogicos identicos. A ocorrencia de solos com maior profundidade efetiva, com melhor drenagem e maior volume de armazenamento de agua, em associacao a maior inclinacao do horizonte plintico no sentido do igarape, aumentando o fluxo de agua nesta direcao, favorecem o aparecimento da vegetacao de mata, enquanto que condicoes opostas a estas favorecem o aparecimento da vegetacao de campo nativo.

Infiltração de água no solo em áreas cultivadas com cana-de-açúcar sob diferentes sistemas de colheita e modelos de ajustes de equações de infiltração

As tecnicas de colheita da cultura de cana nem sempre seguem preceitos conservacionistas, fato que pode influenciar atributos fisicos do solo com consequente alteracao da velocidade de infiltracao de agua no solo. O trabalho realizado teve como objetivo avaliar o efeito de diferentes sistemas de colheita (manual e mecanizada) da cana-de-acucar (crua e queimada), sobre as caracteristicas de infiltracao e verificar a adequacao de modelos matematicos para a estimativa da taxa de infiltracao de agua no solo. Foi utilizado um simulador de chuva portatil calibrado para aplicar uma precipitacao de 60 mm h-1. Os testes de infiltracao de agua no solo foram realizados em tres sistemas de colheita: colheita manual de cana queimada, colheita mecanizada de cana crua e colheita mecanizada de cana queimada. A qualidade do ajuste dos modelos foi avaliada por meio de regressoes nao lineares entre os valores estimados e os valores medios observados em cada tratamento estudado. Nos tratamentos onde foi empregada a colheita mecânica, observou-se uma reducao da taxa de infiltracao final em relacao a area sob colheita manual de cana queimada. A equacao de Horton foi a mais adequada para a estimativa da taxa de infiltracao de agua no solo estudado.

Parâmetros físicos do solo e erosão hídrica sob chuva simulada, em área de integração agricultura-pecuária

This work was carried out in Dourados, Mato Grosso do Sul State, Brazil, in order to evaluate soil erosion and water loss in pasture and in no tillage agriculture in a pasture-agriculture integration system using a portable rainfall simulator. Four rainfall intensities (40, 60, 80 and 100 mm h-1) were studied, each consisting of a treatment arranged in an experimental design in randomized blocks with four replications. Accumulated average soil loss varied from 1.33 to 10.50 g m-2 and water loss varied from 1.34 x 10-3 to 34.64 x 10-3 m3 m-2. The largest soil and water losses occured in the largest rainfall intensities and the no-tillage system had the largest soil loss and the pasture the largest water loss.

Área superficial específica, porosidade da fração argila e adsorção de fósforo em dois latossolos vermelhos

SUMMARY : SPECIFIC SURFACE AREA AND POROSITY OF THE CLAYFRACTION AND PHOSPHORUS ADSORPTION IN TWORHODIC FERRALSOLS The porosity of the clay fraction is very important for the understanding of thephysicochemical phenomena which are relate to the specific surface area of solid particles. Thespecific surface area (S BET ) and porosity of clay fractions of two Rhodic Ferralsols in the stateof Mato Grosso do Sul, Brazil, natural kaolinite (KGa 2 ), synthetic goethite (Gt) and hematite(Hm) were evaluated through adsorption and desorption isotherms of N 2. . Results concerningS BET and particle porosity were related to the maximum P adsorption capacity (P max ) estimatedby the Langmuir isotherm. The predominant pore class in the clay fractions was mesopores.The clay fractions of the soils and KGa 2 adsorbed similar amounts of P per unit area, butdiffered from the quantities of P adsorbed by Gt and Hm. This difference was possibly relatedto the abundance and distribution of OH groups on the surface as well as imperfections on thematerial surface. The iron and aluminum oxides and other amorphous material in the clayfractions of the soils were more important than kaolinite for P adsorption. Kaolinite, the mainphyllosilicate in the clay fractions of LVDf and LVD soils, was less relevant for P adsorption.Index terms: kaolinite, hemathite, goethite, mineralogy, clay, isotherm; phophorus fixation.

Physical properties and particle-size fractions of soil organic matter in crop-livestock integration

Crop-livestock integration represents an interesting alternative of soil management, especially in regions where the maintenance of cover crops in no-tillage systems is difficult. The objective of this study was to evaluate soil physical and chemical properties, based on the hypothesis that a well-managed crop-livestock integration system improves the soil quality and stabilizes the system. The experiment was set up in a completely randomized design, with five replications. The treatments were arranged in a 6 x 4 factorial design, to assess five crop rotation systems in crop-livestock integration, and native forest as reference of soil undisturbed by agriculture, in four layers (0.0-0.05; 0.05-0.10; 0.10-0.15 and 0.15-0.20 m). The crop rotation systems in crop-livestock integration promoted changes in soil physical and chemical properties and the effects of the different systems were mainly detected in the surface layer. The crops in integrated crop-livestock systems allowed the maintenance of soil carbon at levels equal to those of the native forest, proving the efficiency of these systems in terms of soil conservation. The systems influenced the environmental stability positively; the soil quality indicator mineral-associated organic matter was best related to aggregate stability.