Papers

Summary

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 conducted in August and September, 1999 at the Experimental Station of UNESP – Ilha Solteira campus, located in Selvíria (MS). Soil sampling was accomplished according to an appropriate geostatistical analysis design defined as a grid with 150 m length in South direction and 30 m width in North direction. There were 103 points equaly spaced, 10 m apart from each other, and 39 points equaly spaced, 1 m apart from each other, randomly distributed in the grid. From each point defined according to the grid it was taken one sample at the 0,00-0,05 m and one at the 0,15-0,20 m depths. The results were firstly evaluated by exploratory statistics analysis calculating average, frequency distribution, variance, coefficient of variation, and coefficients of kurtosis and skewed. Subsequently, the spatial dependence was verified through semivariogram. The microporosity, total porosity and bulk density attributes followed normal distribution, while the macroporosity and penetration resistance followed the lognormal distribution. Soil moisture presented distribution closer to the lognormal. The largest variation coefficient was verified for macroporosity and penetration resistance. The other evaluations presented variation coefficient below 10%. It was observed moderate spatial dependence for every attribute studied. The spatial dependence reachness varied from 8,36 m (soil moisture) to 58,80 m (penetration resistance).