Spatial variability of the physical properties of andisols in the colombian coffee zone. Variabilidad espacial de las propiedades físicas de andisoles en la región cafetera colombiana.

The  soil  physical  properties  show  spatial  variability  due  to  the  intrinsic  characteristics  and  the  changes  generated  by  soil  management.  Since  this  is  important  for  agriculture,  a  research  was  carried  out  in  order  to evaluate that variability by the deterministic and geostatistical method in two plots of soils coming from volcanic  ash  and  located  in  the  Department  of  Quindío–Colombia.  In  each  farm,  1.0  ha  was  delimited  and soil samples were taken in a grid pattern every 10 m. Sand, silt and clay, humidity retention to field capacity  (FC)  and  wilting  point  (WP),  particle  density  (DP)  and  bulk  density  (DB),  aggregates  stability  (AS),  hydraulic  conductivity  (HC)  and  penetration  resistance  (PR)  were  evaluated.  Most  of  the  properties  showed normal distribution and coefficients of variation from low to intermediate. The spatial variability of the properties was different in both plots, which was attributed to the influence of the geomorphology because  in  the  plot  with  heterogeneous  geomorphology,  5  properties  showed  spatial  tendency,  2  showed  Nugget effect, and in 2 the prediction was not reliable. In the most homogeneous plot, 3 properties showed spatial  tendency  and  the  remaining  7  were  adjusted  to  theoretical  models  with  reliable  results.  Therefore,  the sampling grid system in plots with heterogeneous topography was not the most appropriate for studies with  geostatistical  purposes.  Besides,  the  IDW  method  was  useful  to  expose  the  spatial  variability  of  the  properties  that  did  not  meet  the  geostatistical  assumptions.