Glécio Machado Siqueira

Distribuição espacial da condutividade elétrica do solo medida por indução eletromagnética e da produtividade de cana-de-açúcar

The current agriculture requires the use of new technologies that allow the identification of soil and plant patterns, and the determination of their spatial variability. This work determined the spatial relationship between the sugar cane yield and soil apparent electrical conductivity (ECa) measured by electromagnetic induction (EMI) and soil texture. The experimental area is located in Goiana (Pernambuco State, Brazil) (07°34’25”S, 34°55’39”W). The experimental area was 6.5 ha. Sugar cane yield and soil apparent electrical conductivity (ECa) were measured at 90 sampling points randomly distributed in the study area. Maps of soil electrical conductivity (ECa-V and ECa-H) were similar to that of sugar cane yield. The linear correlation showed values of 0.74 (yield x ECa-H) and 0.85 (yield x ECa-V). The electrical conductivity measured by electromagnetic induction has been shown to be an important tool for predicting the yield of sugar cane. The textural properties (clay, silt and sand) showed high spatial variability.

CORRELACIÓN ESPACIAL ENTRE MALAS HIERBAS EN UNA PRADERA Y SU RELACIÓN CON LA CONDUCTIVIDAD ELÉCTRICA APARENTE DEL SUELO (CE A )

The objective of this study was to evaluate the ecology and, linear and spatial correlation between weeds in and soil apparent electrical conductivity (ECa, mS m-1) in a grassland. Measurements were done in 23/06/2008 (ECa) and 24/06/2008 (weeds). Data were analyzed using classical statistical and geostatistical tools. Most data presented logarithmic frequency distribution, using the residual kriging being necessary. Low values of correlation measures ECa measurements with weeds in the study area were found, being influenced by the topography of the area. The spatial variability maps have showed relationship between weeds and values of ECa (ECa-V and ECa-H), mainly regarding the number of weed species, as there are an increasing number of species with declining ECa values. The maps of spatial variability for weeds demonstrate the dominance of species and endemism of other species.

Spatial soil sampling design using apparent soil electrical conductivity measurements

Soil sampling is an important stage of digital soil mapping. The objective of this study was to characterize the spatial design of soil sampling using soil apparent electrical conductivity (ECa) and its optimized spatial sampling. For the characterization, it was used the Spatial Simulated Annealing (SSA) technique, incorporated on the software SANOS 0.1, and the method of response surface sampling design on the software ESAP 2.35. The ECa was measured at 1,887 points in an area of 6 ha located in the northwestern region of Spain. The EM38-DD equipment (Geonics Limited 2005) was used at 2 depths: vertical dipole (1.5 m effective measurement depth) and horizontal dipole (0.75 m effective measurement depth). Semivariogram showed trend for ECa in vertical dipole (ECa-V) and ECa in horizontal dipole (ECa-H). Software SANOS 0.1 and ESAP 2.35 were used to obtain the 40-point sampling scheme, using the 2 schemes (SANOS and ESAP). ECa-V estimation values at the 1,887 points were calculated with residual ordinary kriging. The sampling scheme obtained from ESAP was better than with SANOS.

CONTINUIDADE ESPACIAL DA CONDUTIVIDADE ELÉTRICA, CONTEÚDO DE ÁGUA E TEXTURA EM UMA ÁREA CULTIVADA COM CANA-DE-AÇÚCAR

Spatial variability of soil attributes affects crop development. Thus, information on its variability assists in soil and plant integrated management systems. The objective of this study was to assess the spatial variability of the soil apparent electrical conductivity (ECa), electrical conductivity of the saturation extract (ECse), water content in the soil (θ) and soil texture (clay, silt and sand) of a sugarcane crop area in the State of Pernambuco, Brazil. The study area had about 6.5 ha and its soil was classified as orthic Humiluvic Spodosol. Ninety soil samples were randomly collected and evaluated. The attributes assessed were soil apparent electrical conductivity (ECa) measured by electromagnetic induction with vertical dipole (ECa-V) in the soil layer 0.0.4 and horizontal dipole (ECa-H) in the soil layer 0.0-1.5 m; and ECse, θ and texture in the soil layers 0.0-0.2 m and 0.2-0.4 m. Spatial variability of the ECa was affected by the area relief, and had no direct correlation with the electrical conductivity of the saturation extract (ECse). The results showed overestimated mean frequency distribution, with means distant from the mode and median. The area relief affected the spatial variability maps of ECa-V, ECa-H, ECse and θ, however, the correlation matrix did not show a well-defined cause-and-effect relationship. Spatial variability of texture attributes (clay, site and sand) was high, presenting pure nugget effect.

ELDERLY LIFE QUALITY DOMCILIED IN CARPINA (PERNAMBUCO STATE, BRAZIL) DETERMINED BY BARTHEL INDEX

The objective of this study was to determine the quality of life in elderly Health Family Units (HFU) in Carpina (PE, Brazil) evaluated by Barthel Index and application of geostatistical tools. The main conclusions are the Barthel Index characterized the elderly of municipality as independent, with scattered cases of dependency in the elderly, being directly related frameworks of advanced age; the sampling scheme was not sufficient to detect the spatial variability of the data.