Análise espacial e estabilidade temporal da armazenagem de água em Cambissolo da região do Vale do Açu, RN

Irrigated fruit growing in the Açu Valley is an important component of the Potiguar agribusiness. Knowledge of the spatial and temporal behavior of water in the soil is essential for precise irrigation management. This study was conducted aiming to analyze, by means of geostatistics, the spatio-temporal variability of water storage in the soil and the temporal stability of these variations. The studies were conducted in an area cultivated with hoses (Manguifera índica L.), irrigated by micro in Alto do Rodrigues, RN. Monitoring soil water was by tensiometers. In the evaluation of temporal stability, we used the techniques suggested by Vachaud et al. (1985) and Kachanoski and Jong (1988). The results indicated adequate geostatistics to describe the spatial dependence structure, and soil water storage present spatial variability in the area, showing the need to manage irrigation differently and not considering the homogeneous area, as is currently done in practice. The water in the soil showed temporal stability in all sampled points. And, this condition provides the identification points in the area that have values representative of the spatial average.A fruticultura irrigada no Vale do Açu é importante componente do agronegócio potiguar. O conhecimento do comportamento espacial e temporal da água no solo é fundamental para um manejo preciso da irrigação. Em função disso, o objetivo desse trabalho foi analisar, por meio da geoestatística, a variabilidade espaço-temporal da armazenagem de água no solo e a estabilidade temporal dessas variações. Os estudos foram realizados numa área cultivada com mangueiras (Manguifera índica L.), irrigada por microaspersão, em Alto do Rodrigues, RN. O monitoramento da água no solo foi por tensiometria. Na avaliação da estabilidade temporal, utilizaram-se as técnicas sugeridas por Vachaud et al. (1985) e Kachanoski e Jong (1988). Os resultados indicaram a geoestatística adequada para descrever a estrutura de dependência espacial, sendo que a armazenagem de água do solo apresentou variabilidade espacial na área, mostrando a necessidade de se manejar a irrigação de forma diferenciada e não considerando a área homogênea, como é feito atualmente na prática. A água no solo apresentou estabilidade temporal em todos os pontos amostrados. E, essa condição, proporciona a identificação de pontos na área que apresentem valores representativos da média espacial

Spatial variability of available water and micro-sprinkler irrigation in cambisol

ABSTRACT The technology of irrigation is vital for agricultural production. Thus, description of spatial patterns of both water application and available water capacity in the soil, as well as their interactions, is essential to maximize efficiency of water use in irrigated areas. The objective of this study was to analyze spatial variability of available water capacity in the soil and water application via irrigation using geostatistics. The experiment was conducted in a commercial mango orchard in Cambisol irrigated by micro sprinkler system, in the municipality of Alto do Rodrigues, RN. Analyses of descriptive statistics and geostatistics were performed using the programs GeoR and GS+. Geostatistics was found suitable for describing the structure of spatial dependence of available water capacity in the soil and the flow rate distributed in the area by sprinklers. Moreover, even with good results for Christiansen Uniformity Coefficient (CU) and Distribution Uniformity Coefficient (DU), the area showed spatial variability of flow rate