Variabilidade espacial de atributos químicos em latossolo e argissolos

O trabalho teve como objetivo caracterizar a variabilidade espacial de atributos químicos de Latossolos e Argissolos, sob cultivo de cana-de-açúcar em áreas com variações na forma do relevo. No presente estudo utilizou-se duas áreas, sendo uma em Latossolo em pedoforma convexa (158ha) e a outra em Argissolo na pedoforma linear (172ha). Foi coletada amostra de solo em malha na profundidade de 0,00-0,50m, realizando-se análise química de cada ponto amostrado. Os maiores coeficientes de variação e alcances foram observados na pedoforma convexa (Latossolo). Portanto, o Latossolo inserido na pedoforma convexa apresentou maior variabilidade espacial para os atributos químicos em relação ao Argissolo na pedoforma linear. O latossolo inserido pedoforma convexa necessita de maior número de pontos de coleta por apresentar maior variabilidade espacial. Recomenda-se que o intervalo de amostragem seja igual ao alcance da dependência espacial, para associar menor esforço de amostragem com maior representatividade.

Variabilidade espacial da textura de um latossolo sob cultivo de citros

O relevo influencia a variabilidade da textura, uma vez que condiciona o tempo de exposição dos materiais à ação do intemperismo. Neste trabalho, desenvolvido no município de Gavião Peixoto (SP), objetivou-se caracterizar a variabilidade espacial da textura de um Latossolo Vermelho distrófico sob cultivo de citros. A encosta foi dividida em três segmentos: topo, meia encosta e encosta inferior. O solo foi amostrado em malha, com intervalos regulares de 50 m, perfazendo o total de 332 pontos em uma área de 83,5 ha, nas profundidades de 0,0-0,2 m e 0,6-0,8 m. Os dados foram submetidos à análise estatística descritiva e geoestatística (modelagem de semivariogramas e mapas de krigagem). O comportamento espacial da textura de latossolos está diretamente relacionado com as formas do relevo neste estudo, que controla o sentido dos fluxos de água superficial e subsuperficial. O conceito de homogeneidade da distribuição de argila no perfil dos latossolos é uma informação que pode ser ajustada pelo conhecimento do padrão espacial dessa distribuição em diferentes formas do relevo.

Variabilidade genética do peso adulto de matrizes em um rebanho Nelore do Estado de São Paulo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos da temperatura e da movimentação do ar sobre o isolamento térmico do velo de ovinos em câmara climática

Foram utilizados dez ovinos da raça Corriedale - cinco machos e cinco fêmeas com pesos entre 52,2 e 87,6 kg - com o objetivo de avaliar o efeito da combinação da movimentação do ar (0 e 5,0 m/s) com a temperatura do ar (25, 30 e 40ºC) sobre a temperatura retal (T R, ºC), da epiderme (T E, ºC), da superfície do velo (T V, ºC) e do interior do velo (T I, ºC) e a espessura do velo (E V, cm) e suas relações com o isolamento térmico do velo. A presença de vento não teve efeito sobre as variáveis estudadas, o que sugere que fluxo de ar (<5,0 m/s) paralelo ao eixo corporal do animal tem pouco efeito sobre o isolamento térmico do velo, independentemente da temperatura do ar, que se mostrou altamente correlacionada, de forma positiva, com as temperaturas retal, do velo, do interior do velo e da epiderme. Sob temperaturas inferiores a 30ºC, a transferência de calor através do velo ocorreu via condução e convecção livre, enquanto sob altas temperaturas (>40ºC) o fluxo de calor sensível não foi significativa.

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.

Variabilidade espacial da resistência do solo à penetração e do teor de água em sistema de plantio direto na cultura da soja

A harmful and limiting factor regarding culture productivity is soil compaction, a parameter that can be quantified by the resistance of the soil to penetration and highly influenced by water content. These variables present spatial and temporary variability, characteristics which can be determined by the geostatistical technique. In the light of the above, the present work had as its objective the study of spatial variability of soil resistance to penetration (RP) and water content in the soil (U) in soy culture. The RP values at depths of 0,00-0,10; 0,11-0,20 and 0,21-0,30 m varied from 2,9 to 4,28 MPa and are considered harmful to the root development of legumes, although they have not influenced soy productivity which was 3887 kg ha(-1). The medium water content of the soil was between 0,210 and 0,213 kg kg(-1) for the three depths studied. The resistance of the soil to penetration, expressed through semivariograms, presented spatial dependence at all depths, being adjusted to the spherical model at depths of 0,00-0,10m and exponential at depths of 0,110,20 and 0,21-0,30 m. The spatial variability for all studied layers presented a range of about 20m. The water content in the soil did not present spatial dependence for the depths, presenting randomized distribution.

Variabilidade espacial de atributos químicos em um Argissolo sob pastagem

Studies show the importance of knowing the variability of soil attributes for a more efficient management. This work was carried out to evaluate the spatial variability of the chemical attributes of an Ultisol, cultivated with Brachiaria decumbens pasture in Alegre - ES. Soil samples were collected at a depth of 00-0.2 m, at the crossing points of a regular grid with 10 m-intervals, comprising a total of 64 points. Data were submitted to descriptive statistics, geostatistics and kriging interpolation analysis. The coefficient of variation was low for pH, high for Al and m%, and medium the other attributes. The attributes pH, P, H+Al and m% presented strong dependence, and the other moderate dependence. The attributes presented a spatial dependence structure, allowing their mapping by geostatistics techniques.

Variabilidade da precipitação pluvial na UGRH do Médio Paranapanema, Estado de São Paulo

The purpose of this work was to analyze the variability of pluvial precipitation at the Mid-Paranapanema Hydric Resources Management Unit (UGRI II-17), both spatially and temporally. To that effect, 33 pluviometric series were used, obtained from the National Water Agency (ANA), for the period from 1940 to 2000. The averages, standard deviation, upper and lower quartiles, maximum rainfalls, within the analyzed period, as well as the anomalies in these series, were calculated. The anomalies of the 1982/1983 El Nino, as well as the classification of homogeneous areas inside the basin were also calculated. Variability was observed from one year to the other, with rainier years - for example, 1982 and 1983 - and drier years - such as 1985 and 2000.

Avaliação da variabilidade genética em quatro gerações de Eucalyptus urophylla S.T. Blake por meio do marcador molecular RAPD

Molecular markers have gradually replaced morphological markers in population studies. The advantages of molecular markers are the speed and precision of evaluations, mainly for long cycle cultures, where determinate traits can take years to manifest. The principle objectives of this research were to assess variability and genetic distances in four generations of Eucalyptus urophylla and provide data that help with the continued improvement of these materials. The populations can be found at the Experimental Forestry Sciences Station, Anhembi, SP, belonging to the College of Agriculture Luiz de Queiroz of São Paulo University. The initial base population was introduced by seeds collected in indonesia and designated P0 generation. The subsequent segregated generations, derivatives of recombination starting with open pollination, were designated P1, P2, and P3. One hundred and seventy four individual trees representing the four generations were analysed. The RAPD technique allowed the identification of 86 loci that were analysed with the Jaccard Coefficient, generating a genetic similarity matrix, permitting the estimation of genetic distances. The genetic distance of generation PO was 0.3338333, P1 was 0.336824, P2 was 0.40000, and P3 was 0.381093. In percentage terms the genetic distances between individuals grew in relation to base population, being 0.15% for generation P1, 18.93% for P2, and 13.31% for P3. This shows an increase in genetic variability with the advance of the program, despite the selective processes. From this came the belief that the initial base population was resulting from seed collection from isolated trees. These populations, although going through successive selections, had a high cross efficiency through satisfactory pollination, which then permitted genetic variation to increase, the outcome of effective recombination between individuals. Generations P2 and P3 gave a better perspective for the continuance of the improvement program due to the high number of different groups with standard genetic distances of 35%. The selections made between the diverse genetic groups allowed the efficient use of genetic variability evaluation.

Caracterização silvicultural, botânica e avaliação da variabilidade genética por meio do marcador molecular RAPD em um teste de progênies de Eucalyptus urophylla S. T. Blake

Molecular markers have recently been incorporated into genetic improvement programs. They are already considered as powerful tools with several different uses, for instance the monitoring of genetic variability in tree populations. The main objectives of this study were to evaluate genetic variability in Eucalyptus urophylla progenies and together with silvicultural and botanical information, provide assistance to the improvement program. The Eucalypts population is located at the Experimental Forestry Sciences Station, Anhembi, SP, which belongs to the College of Agriculture Luiz de Queiroz. Sixty-nine progenies were analysed representing one individual by family in open pollinated Eucalyptus urophylla trees. The RAPD technique allowed the identification of 72 loci that were analysed using Jaccard's Coefficient generating a genetic similarity matrix to permit estimation of genetic distances. The results obtained showed genetic distance between individuals of 0.40 with 12 groups of genetic variability using a standardised distance of 40%. The progenies showed different bark patterns, allowing the establishment of bark groups. The groups formed based on genetic distances obtained using DNA analysis did not correspond to those based on bark pattern. Genetic selection was simulated in which silvicultural and genetic variability data were linked, thus avoiding excessive variability losses. The simulation of controlled crossings allowed the maximum genetic difference to be obtained linked with height and individual bark roughness.

Variabilidade espacial da estabilidade de agregados e matéria orgânica em solos de relevos diferentes

Soils submitted to the same management system in places with small relief variation manifest different spatial variability on their attributes. The objective of this work was to evaluate the spatial variability of the geometric medium diameter, aggregates in the >2 mm class, aggregates in the 2-1 mm class and organic matter of an Oxisol under culture of the sugarcane. Samplings of the soil in regular intervals of 10 m, in grid form, totaling 100 points, collected in the depths of 0.0-0.2 m and 0.2-0.4 m were made. Data were submitted to descriptive statistics, geostatistics and in sequence to kriging analyzes. Values of the variation coefficient were low for organic matter in the depth of 0.0-0.2 m, mean in the depth of 0.2-0.4 m, high for geometric medium diameter and mean for aggregates in the >2 mm class, aggregates in the 2-1 mm class in all studied depths. The occurrence of space dependence was observed for all the variables, and the largest ones were observed in the depth of 0.0-0.2 m. Small variations in the forms of the relief condition spatial variability differentiated for organic matter and stability of aggregates in the studied depths.

Variabilidade genética intrapopulacional em Myracrodruon urundeuva Fr. All. por marcador AFLP

Levels of genetic variability for in situ and ex situ genetic conservation were estimated in a population of Myracrodruon urundeuva using the PCR (polymerase chain reaction) technique with the AFLP (Amplified fragment-length polymorphism) genetic marker. Seeds for progeny tests were collected from 30 open-pollination trees (matrices) at Paulo de Faria Ecological Station - SP. From this genetic material, three progeny tests were installed on the Teaching and Research Farm of Ilha Solteira Faculty of Engineering - University of São Paulo State (UNESP), which is located in Selvlria - MS, Brazil. The analysis by genetic marker was conducted with three combinations of different starters EcoRl-Msel, resulting in a total number of 137 polymorphic bands, thus forming a table of binary data. These data were used for the analysis of genetic divergence and distance between progenies. High levels of genetic divergence were observed among families. Based on the Analysis of Molecular Variance (AMOVA), it was shown that 16.2% of genetic diversity is found among progenies and 83.8% within progenies, which suggests deviances of random matings. The grouping of progenies, based on genetic distances, suggests that progenies deriving from trees which are close to each other tend to be more similar. This, in turn, indicates that the population originating the seeds may be genetically structured.

Variabilidade espacial das propriedades físicas e químicas do solo em áreas intensamente cultivadas

The spatial variability of physical and chemical properties of soil were evaluated to provide subsidies for management of the agricultural input. The chemical variables: P, organic matter (OM), K, Ca, Mg, pH, CEC and base saturation (BS); and physical variables: sand and clay were analysed. Soil samples were collected at two depths (0-0.2 and 0.6-0.8 m) located at irregular mesh of sampling in the region of Monte Alto, in a Yellow-Red Podzol (Alfissolo) (PVA), under different managements, resulting in 88 points in 1465 ha of total area; and at the region of Jaboticabal in a Red Latosol (LV) cultivated with sugarcane, resulting in 128 points in 2597 ha of total area. The chemical and physical soil properties studied showed spatial dependence, except CEC in 0.6-0.8 m layer for LV; Ca and clay at 0-0.2 m layer and P, OM, K, Mg, sand and clay in 0.6-0.8 m layer for PVA. The chemical and physical variables studied were adjusted to spherical and exponential models and some of them showed semivariogram without defined structure. The PVA showed low spatial continuity of chemical and physical properties, mainly in 0.6-0.8 m layer, which suffers less antropic influence. The LV soil showed more homogenous zones of fertility and granulometric composition.