Abstract

OBANDO MONCAYO, Franco Humberto; VILLEGAS HINCAPIE, Andrés Mauricio; BETANCUR P., Jorge H.  and  ECHEVERRI TAFUR, Leyder. SPATIAL VARIABILITY OF CHEMICAL AND PHYSICAL PROPERTIES OF A SANDY TYPIC UDIVITRANDS IN THE COLOMBIAN CENTRAL ANDEAN ZONE. Rev. Fac. Nac. Agron. Medellín [online]. 2006, vol.59, n.1, pp.3217-3235. ISSN 0304-2847.

A study of the spatial variability of the chemical and physical properties of a Sandy Typic Udivitrands was conducted in the Tesorito Experimental Farm of Universidad de Caldas, located in the Colombian Central Cordillera at 5° 01'47" N, 75° 26' 03" W and 2280 m elevation. The experimental plot was located in a Coluvial Piedmont with previous and current soil use and management based on pastures, moderately cold weather fruits and horticultural crops. A systematic sampling of an approximately 30 m grid was carried out at 15 cm depths with an effective area of 3,96 ha for 60 sites. The geostatistical analysis was carried out in three stages: 1) exploratory analysis of the data using the STATGRAPHICS Plus v 2.0 and SPSS 9.0 software packages; 2) structural analysis or "semivariography"; 3) interpolation by punctual Kriging using the geostatistial package GS + version 5.3b.  Spherical and exponential models best fit the theoretical models except for DPM (Weighted Mean of Water Stable Aggregates) which better fit a linear model (pure Nugget). Ranges for spatial dependence for the analyzed variables were within the maximum distance ( 350 m) of the sampling area considered for the calculation of the semivariograms, except for phosphorous that showed a range of 479,4 m. Range fluctuated between 33,9 m for Na and 308,5 m for DPM. Spatial variability of soil attributes of the experimental plot was high, being higher for chemical properties. Geostatistical analysis allowed visualization of the spatial variability of soil structural deterioration which coincided with the area of greatest chemical variability.

Keywords : geostatistical analysis; spatial variability; site specific management.

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