This work explored the applicability of the fractal theory for studies into space variability of soil aggregation. Fractal geometry has become a model for soil size particle distribution. The distribution of soil aggregates in terms of its mass was obtained, and model parameters such as the fractal dimension D, which is a representative measure of the soil fragmentation (the larger its value, the larger the fragmentation), and the largest aggregate size RL were defined as descriptive tools for soil aggregation. […]

The spatial variability of soil water infiltration rate and A horizon thickness were studied in a Red-Yellow Podzolic soil (Kandudalf) showing erosion signs, located in Vera Cruz, SP. Field measurements were taken in regular 5 meter spacing square grid, resulting in 64 sampling points where the infiltration rate at the A, E and B horizon, and A horizon thickness were determined in coffee, pasture and natural vegetation. Statistical analysis showed high variability in the soil water infiltration rate and in […]

In a natural landscape, the soils present a wide variation on morphological, physical, chemical and mineralogical properties due to several soil formation factors. In a cultivated landscape others sources of variation may be present, such as anthropogenical processes. The knowledgement of these variations is important to soil survey, development of sampling designs and soil management practices. This work aimed to study the spatial variability of some physicals attributes of a Dystrophic Red Latosol cropped in no tillage system. It was […]

The objective of this work was to studying the spatial variability of some chemical properties of a saline-sodic soil of alluvial origin, in the Irrigated Perimeter of São Gonçalo, district of Sousa-PB, Brazil. At an experimental area of 2912 m2, soil samples were collected in a grid with a spacing of 4 x 4 m, at a layer depth of 0 to 0.30 m. The data analysis was carried out by means of descriptive statistics and geostatistics. The results showed […]

This study was carried out at the Experimental Station “La Poveda” in Arganda del Rey (Madrid), with the following geographical coordinates: latitude 40º 19′ N; longitude 3º 19′ W Gr; and altitude 550 m. The main objective was to study the spatial variability of chemical and physical properties of a Typic Xerofluvent under three cultivation systems. Sampling for the study of spatial variability was performed according to an appropriate geo-statistical analysis in two directions. Spatial variability was observed with respect […]

A field experiment, located on a private farm close to Piracicaba, State of São Paulo, Brazil, was conducted on a severely eroded soil (Ultisol-Entisol association), which has been planted with sugar cane for the last 30 years. The objective was to characterize the spatial variability of soil and plant attributes. An area of 50 by 70 m was divided into 10 columns and 14 rows in a grid of 5 m, resulting in 140 sampling points. Soil samples were collected […]

Two methods were evaluated for scaling a set of semivariograms into a unified function for kriging estimation of field-measured properties. Scaling is performed using sample variances and sills of individual semivariograms as scale factors. Theoretical developments show that kriging weights are independent of the scaling factor which appears simply as a constant multiplying both sides of the kriging equations. The scaling techniques were applied to four sets of semivariograms representing spatial scales of 30 x 30 m to 600 x […]

The variability of leaf nutrient concentrations (nitrogen, phosphorus, potassium, calcium, magnesium, zinc, copper, manganese, and iron) was assessed in a twelve-year-old orange orchard, cv. Pêra, grown on a dystrophic Yellow Latosol of medium texture plain relief, in Governador Mangabeira, State of Bahia, Brazil, 1990. A transect consisting of 50 trees, spaced four meters apart, was sampled. Twenty leaves were collected from each tree. The leaves were taken from four different points of the crown, opposite two by two, and from […]

With the objective of assisting sampling systems and planning orange experiments, soil variability was assessed in a twelve-year-old orange orchard, cv. Pera, grown on a dystrophic Yellow Latosol of medium texture plain relief, in Governador Mangabeira, State of Bahia, Brazil, 1990. A transect consisting of 50 trees, spaced 4 m apart, was sampled. Soil samples were taken from a fixed point under the tree drip line on the successively fertilized strip. Results showed that only phosphorus and gravimetric soil moisture […]