Variabilidade espacial do fósforo e das frações granulométricas de um Latossolo Vermelho Amarelo

This study was conducted to study the spatial variability of phosphorus, estimating it through cokriging taking as covariables the size fractions of soil. The study was conducted at the experimental farm INCAPER-ES. The soil was sampled in the canopy projection of culture and depth of 0-0.20 meters in an irregular mesh with 109 points. The data were initially submitted to a descriptive analysis and correlation. Through geostatistics was made the adjustment of the variograms. The P showed significant correlation with the sand and clay fractions indicating that areas with higher concentrations of clay have lower availability of this nutrient. Both fractions have equal performance as co-variable in the estimate of the levels of P in the soil.

Variabilidade espacial da textura de um argissolo vermelho amarelo sob cultivo de pastagem e vegetação nativa

The study of the spatial variability of soil attributes under different crop helps the study of changes due the management. This research was carried out to determine spatial variability the particle-size distribution, using of the classic statistic and geostatistics, of a soil cultivated with pasture and native vegetation. Soil samples were collected in the layer 0-0.20m, at the crossing points of a regular grid with 10m-intervals, summing up 64 samples points in each area. In the pasture area the fractions of coarse and total sand presented larger mean values in relation to the native vegetation, and negative correlation with the altitude of the points samples in the two areas. All of the fractions presented moderate to high spatial dependence in the two areas and with the defined still, with exception of the fine sand and the silt in the pasture. Much of this variability occurs as a function of water erosion.

Sistemas agroflorestais e seus efeitos sobre os atributos químicos em Argissolo Vermelho-Amarelo do Cerrado piauiense

This study aimed to quantify the effects of agroforestry systems (AFS), with different periods of adoption, and slash and burn agriculture (SB) on the chemical attributes of an Ultisol in the 'Cerrado' of Piaui State, Brazil. In two distinct climatic seasons (dry and rainy) four systems were studied: AFS with six (AFS6) and thirteen years (AFS13) of adoption, an area under SB and a native forest (NF), as a reference. In the AFS, in all depths, higher reduction in the Al3+ and H+ + Al3+ contents were observed as well as an increase of pH value and contents of nutrients (N, P, Ca, Mg and K) and organic carbon in soil. In the soil under SB, only in superficial layers, the ash deposited on the soil caused an increase in contents of nutrients, except for P, which was higher in all the depths. There was significant seasonal effect in the contents of nutrients, reducing in the rainy season. Agroforestry systems promoted increase in the nutrient contents of an Ultisol and can be considered useful to improve soil chemical quality in areas of 'Cerrado' of Piau State, Brazil.

Atributos físicos de latossolo vermelho sob pousio ou cultivado com forrageiras tropicais sob pastejo

The objective was to study the physical attributes of an Oxisol under fallow or planted with tropical grasses under grazing. The experiment was conducted under the experimental design of randomized blocks in split-plot 2 x 5, being five types of use of soil (Brachiaria ruziziensis, Panicum maximum cv. Aries, Brachiaria brizantha cv. MG5, Panicum maximum cv. Mombaca and fallow) and two evaluation periods (after the first and after the second grazing), with four replications. We evaluated the characteristics of soil bulk density, total porosity, microporosity and macroporosity, after the first and second grazing, and soil resistance to penetration after the second grazing. In layer of 0.00 to 0.10 m, the macroporosity was affected by the interaction between types of use and evaluation periods, while the microporosity and total porosity were reduced and the density was increased from first to second evaluation time. In the subsurface layer (0.10-0.20 m), there were significant effect only of evaluation time, on the macroporosity, total porosity and density. The porosity were reduced, while the density increased from first to second evaluation time. No significant effects of types of use of soil on penetration resistance in all layers studied. The maintenance of an Oxisol under fallow or cultivation with tropical grasses subjected to grazing cattle causes a reduction in total porosity and increased density of surface soil layers (0 to 0.10 m) and subsurface (0.10 - 0.20 m), without promoting changes on resistance to penetration mechanics.

Qualidade física de um Latossolo Vermelho em recuperação há dezessete anos

The bulk density and resistance to penetration as indicators of recovery were studied with the objective to investigate the physical quality of a Red Latosol (Oxisol) under restoration for 17 years using green manures, soil correction, gypsum and pasture. The experimental design was a completely randomized with nine treatments and four replications. The treatments were: control (tilled soil without crop); Stizolobium aterrium; Cajanus cajan until 1994 and then substituted by Canavalia ensiformis; lime+S. aterrimum; lime+C. cajan until 1994 and then substituted by C. ensiformis; lime+gypsum+S. aterrimum; lime+ gypsum+C. cajan until 1994 and then substituted by C. ensiformis, the treatments were installed in 1992 and remained for seven years, in 1999 Brachiaria decumbens was planted; two other controls (native vegetation and exposed soil) were also used to compare. Bulk density, resistance to penetration and soil moisture were evaluated. The results were analyzed performing analysis of variance and Tukey test at probability of 5% to compare means. The treatments of reclamation are improving the physical qualities of soil and the results of treatment with C. cajan/C. ensiformis, lime and gypsum attained physical conditioning similar to soil under natural conditions.

Adubação verde em Citrus: Influência na porosidade e retenção de água de um latossolo vermelho-escuro do noroeste do estado de São Paulo

The objective of this research was to study the porosity, bulk density and retention of water of an Oxisol, located in the Northwestern region of Sn̄o Paulo state, Brazil. The soil was cultivated with Citrus sp., to which green manure was applied between rows for three years. Each of six species of green manure crops (Crotalaria juncea L., Mucuna deeringiana Steph. & Bart., Canavalia ensiformis L. DC., Cajanus cajan L., Lablab purpureum L. and Ricinus communis L.) were seeded for three years (1995, 1996 and 1997) between Citrus rows, plus a treatment with a mix of all six species and a control (natural regrowth af vegetation). The experimental design was a randomized complete block design, with four replications for each of the eight treatments. Water retention, microporosity, macroporosity, total porosity and bulk density were analyzed in the beginning (1995) and end (1997) of the experiment, at three depth ranges (0-0.10; 0.10-0.20 and 0.20-0.40m). We concluded that there were statistically significant differences for bulk density, macroporosity, total porosity and retention of water among the different soil depth ranges; there were no significant differences among treatments though.

Efeitos de sistemas de preparo do solo no potencial matricial de um Latossolo Vermelho (Oxisol)

The present work aimed to investigate which was the soil tillage system that better fits for conditions of intensive agriculture, on the region of Selviria-MS. The main objective of this paper was to study the conservation and availability of water in the soil profile. In order to evaluate the soil matric potential in field conditions, readings were accomplished, using tensiometers with a mercury gauger. Matric potential was measured at 0.10 m depth, during the vegetative period of Triticum aestivum L. and at four depths 0.10; 0.20; 0.30 e 0.40 m during the vegetative period of Phaseolus vulgaris L. The study areas were located in the municipal district of Selviria, MS, Brazil. The used experimental set-up was entirely random designed, with treatments disposed in strips; three treatments and four repetitions were used. In the different treatments, soil matric potential was determined. Result allow to conclude that the water matric potential was highest for no-tillage and minimum tillage; however, it was also shown that these two tillage systems, allowed to conserve more water in the soil, when compared to the conventional tillage. In the last cycle of the Phaseolus vulgaris L. crop, no-tillage presented smaller storage of water in the soil, compared to the minimum tillage.

Erosão hídrica de Latossolo Vermelho muito argiloso relevo ondulado em área de pós-plantio de eucalipto no Vale do Rio Doce, região Centro Leste do Estado de Minas Gerais

The erosion caused by running water constitutes important cause of environmental degradation and productivity reduction, which justifies its evaluation in areas of eucalypt commercial plantations, mainly in ondulated slope conditions. The present study was intended to evaluate the influence of different management systems, in an undulated eucalypt pos-planting area, upon soil and water losses by erosion. The experiment was installed in a very clayey Red Latosol (Oxisol) under three eucalypt management systems (downhill planting with burning of crop residues - EDq; downhill planting with maintenance of crop residues on soil surface - ED; level planting with maintenance of crop residues on soil surface - EN), native forest (FN), bare soil (SD), and native pasture (PN). The soil and water losses evaluations were performed in standard plots installed in the field. All eucalypt systems presented very low values of soil losses in relation to the established tolerance limit, indicating the adequacy of these management systems concerning water erosion. The sustainability of these environments regarding erosion is indicated by the fact that soil losses in eucalipt were very close to those observed in native forest (reference).

Estudo quantitativo da lágrima pelo teste de fenol vermelho na população brasileira

Purpose: To detect normal values of red phenol thread test in the Brazilian population and compare it between different races, age and sex. Methods: 280 white individuals (560 eyes) and 280 non-white individuals (560 eyes) were analyzed regarding sex and age, and analyzed using the Phenol Red test. Individuals with ocular diseases, contact lens or ocular drug users were excluded from this study. Results: Of the 1,120 evaluated eyes, the mean ± standard deviation result was 19,77±7,90 mm. Conclusion: The mean result found in this study was an intermediate value compared to the previously studied populations (Japanese and American).

Propriedades físicas e infiltração de água de um Latossolo Vermelho Amarelo (Oxisol) do noroeste do estado de São Paulo, Brasil, sob três condições de uso e manejo

This study presents the results obtained in a field experiment carried out at Glicério, Northwest of São Paulo state, Brazil, whose objective was to analyze changes of selected soil physical properties and water infiltration rates on a Yellow-Red Latosol, under three different management conditions. The experimental design was arranged as completely randomized split-block with twelve treatments, which corresponded to four depths (0-0.05 m; 0.05-0.10 m; 0.10-0.20 m and 0.20-0.40 m) and three conditions of soil use and management with four replications. The soil surface conditions were: conventional tillage (one disking with moulboard plus two levelling passes with harrow), nine months before starting filed experiences; recent conventional tillage (also one disking with moulboard plus two levelling passes with harrow) and native forest. The conventional tillage areas were cropped for about fifteen years with annual cultures. The considered soil general physical properties were: macroporosity, microporosity, total porosity, bulk density, soil moisture and penetration resistance and, in addition; soil water infiltration rates were also recorded. According to our results, differences on general soil physical properties and infiltration rates appeared when both tilled sub-treatments and native forest were compared. Both, plots recently prepared by conventional tillage and those prepared by tillage but left nine months in rest, presented a statistically significant decrease of constant (final) water infiltration rates of 92.72% and 91.91% when compared with native forest plots.

Mapeamento da produtividade e perímetro do tronco de clones de seringueira em argissolo vermelho amarelo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Propriedades físicas e indicador de qualidade de um latossolo vermelho submetido a diferentes sistemas de uso e manejo

The conventional system for soil management and preparation has the intensive mechanization as its basic principle and that changes soil properties, especially physical ones, faster and significantly. This study aimed to obtain and compare physical properties such as distribution of particle sizes, density, distribution of pore sizes, curves of water retention and degradation index of a Red Latosol, under intensive cultivation and no-cultivation for six years. Soil samples were collected at depths of 0.1, 0.2, 0.3, 0.4, 0.6, 0.8 and 1.0 m. There was a clay increment as a result of cultivated soil increase. The no-till soil density decreased as depth increased; however, in the arable layer (0.3 m) of the cultivated soil, the opposite was verified. The largest volume of pores was verified in the cultivated soil, especially in the superficial layers. In the smallest applied tension (0.001 MPa), the cultivated soil retained more water; however, starting from 0.033 MPa, the highest humidity values occurred in the no-till soil. The highest degradation index was observed at a depth of 0.1 m in no-till soil. However, that value was superior (0.020) to what is physically considered very poor soil.

Propriedades físicas de um latossolo vermelho cultivado no sistema plantio direto

The pressure caused by agricultural machinery traffic many result in soil compactation in no-tillage system. The aim of this work was to evaluate no-tillage system onset,time on some physical properties, index S and organic matter (OM) of an oxysol located in Jaboticabal, Sao Paulo State, Brazil. The experiment had completely randomized split-splot design. The treatments consisted of four no-tillage systems: no-tillage for 2 years, no-tillage for 4 years, no-tillage for 6 years and one natural wooded area. The evaluated layers were: Q-0.10m, 0.10-0.20m and 0.20-030m. The following were determined: soil porosity, soil aggregates, bulk density, index S and organic matter. The results were submitted to variance analysis and when there was a difference between averages, Tukey's test was used to compare them. The natural wooded area showed higher organic matter, macroporosity, hydraulic conductivity and Index S. There was no difference between the studied parameters, showing that the no-tillage system for six years was not enough to change the soil physical property.

Propriedades químicas de um latossolo vermelho de cerrado cultivado com algodão sob diferentes preparos e adubações

The high rate of mineralization of organic matter on savannah soils, which is reached fi ve times faster than in temperate regions, leads us to the challenge of electing the best system of management that maintains and/or increase it in soil, guaranteeing its quality and sustainability. In this sense the present research aimed to study the effects of green, organic and mineral manure on the chemical properties on the chemical properties of an Oxisol, on Savannah area, cultivated with cotton (Gossypium hirsutum) under conventional tillage and no-tillage in the pasture fi eld (Brachiaria decumbens) for 20 years. The experimental design was a randomized block design with split plots. The main plots consisted of two treatments: conventional tillage and no-tillage, and the subplots of six treatments: control (no fertilizer), mineral fertilizer recommended for the crop, according to the soil chemical analysis, organic fertilizer (cattle manure - 20 t ha-1), organic fertilizer (cattle manure - 20 t ha-1) + 1/2mineral fertilization recommended according to the analysis of soil, green manure-1 (Crotalaria juncea) and green manure-2 (Pennisetum americanum). There were studied the following soil chemical properties: P, OM, pH, K, Ca, Mg, Al, Al + H, S, exchange capacity cations and base saturation. The soil samples for the analysis were performed on layers of 0,00-0,05 m, 0,05-0,10 and 0,10-0,20 m. Then it came the following conclusions: the fertilization interfere in soil chemical properties and the preparation did not interfere, the cattle manure and its association with the mineral fertilizer caused increasing level elements in the soil, Crotalaria juncea and Pennisetum americanum did not infl uence on soil chemical properties.

Influência do sistema de preparo e manejo de um latossolo vermelho nas suas propriedades físico-hídricas

The intensive use of the land for agricultural propose causes a series of modifications in attributes, which can take to soil degradation. In this context, the main goal of this research was to evaluate the influence of the soil tillage systems and management on its physical and hydric characteristics. The evaluations were carried out in July of 1999, at experimental plots of a Latossolo vermelho, a clay oxisoil, in the Faculdade de Engenharia Agrícola of the UNICAMP, at the county of Campinas, state of São Paulo. These plots were managed with the following treatments, along a period of eight years: no-tillage, chisel ploughing, conventional system with disk ploughing and revolving hoe. The evaluated physical and hydric parameters of the soil were: soil bulk density, particle density, total porosity, macro-porosity, micro-porosity, soil-water retention curve, hydraulic conductivity and basic infiltration. Significant differences were observed between the treatments on soil bulk density, infiltration, total porosity, macro-porosity and the micro-porosity. The chisel ploughing and no-tillage systems presented the higher values of soil bulk density; nevertheless in these conservationist systems were observed the higher values of basic infiltration.