State-space approach to evaluate spatial variability of field measured soil water status along a line transect in a volcanic-vesuvian soil

The spatial structures of soil water status, in terms of soil water content θ and tension h, had been examined on a bare volcanic soil in Ponticelli, Naples (Italy). Measurements were made in situ at 0.3 m depth on two transects consisting of 50 positions 1 m apart. The ACF and the PACF were used to identify the univariate ARMA(1,1) model for the analyzed series and the AR(1) model for the extracted signals. Relations with a state-space model are investigated and a bivariate AR(1) model fitted. The simultaneous relations between θ and h are considered and estimated.