VARIABILIDADE ESPACIAL DE ATRIBUTOS FÍSICO-HÍDRICOS DO SOLO EM ÁREA IRRIGADA

Abstract

The optimization of irrigation water use is a task that involves a series of variables. The knowledge about the soil, soil, implements and culture are used on irrigation management. Geostatistics is a prominent tool on irrigation management because it helps in detailing the characteristics of an area, making it more accurate. The objective of this work was to determine and spatialize physical-hydric attributes and soil organic matter in a central pivot irrigated area at the Goiano IF - Campus Ceres - GO. The study area was sampled in 8 transects spaced 45° apart, and 9 meters between points at depths 0 to 10 cm and 10 to 20 cm. The evaluated attributes were: clay (ARG), sand (ARE), silt (SIL), soil organic matter (SOM), soil density (DS), particle density (PD), total porosity (TP) and infiltration rate at 19 minutes (TI19).The values of maximum, minimum, average, median, standard deviation, variance, coefficient of variation (% CV), kurtosis, asymmetry and normality tests were analyzed in the exploratory statistic Shapiro-Wilk and Komorogov-Smirnov. The variograms were calculated and later adjusted to theoretical models and then validated by the cross validation technique. The attributes interpolation was krigagem and presented spatial variability. The exploratory analysis indicated large amplitude of the TI19 data, which led to a high % CV. The same happened to silt. Only clay, Ds, Pt and MOS in depth of 10 to 20 cm obtained normal distribution. The Ds was on average above the level of soil compaction. All the evaluated attributes showed moderate to strong spatial dependence and obtained adjustments to the gaussian and exponential. The attributes sand and silt in the depth of 10 to 20 cm did not present range, indicating soil homogeneity. The infiltration rate at 19 minutes indicates correlation with clay and total porosity. Geostatistics was adequate on the study of physical-hydric characteristics in irrigated area by central pivot. The study shows that there is unevenness in the physical-hydric characteristics of the soil, which can be useful in planning irrigation management and experiments implementation.