Spatial dependence of selected physico-chemical properties in a major rubber growing soil in Sri Lanka
2009
Mapa, R.B. | Attygalle, T.R. | Perera, S.P. | Silva, S.N. | Dharmakeerthi, R.S.
If soil properties are spatially dependent, this information could be used to delineate management units for site-specific fertilizer application. Spatial dependency of soil pH, organic carbon (OC), gravimetric water content (g ), available P (Pa ), exchangeable K, Mg and Ca (Kex, Mgex, and Ca , and Caex, respectively) were evaluated using geostatistical methods in a , respectively) were evaluated using geostatistical methods in a ex rubber fi eld on Red Yellow Podsolic soils (Typic Paleudults), a major rubber growing soil in Sri Lanka. Soil samples were collected at 5 m intervals along a linear transect of 150 m from crest to bottom in a hilly landscape. Soil pH, OC and g showed a low variability (CV<15%), showed a low variability (CV<15%), g Pa and Caex showed a very high degree of variability (CV>50%), while Kex and Mgex showed a medium variability. Variation in measured soil properties showed some spatial structure. Spatial dependence of available P was poor (81% nugget variance), while that of pH was very high (6% nugget variance). The distance within which the soil properties were spatially correlated ranged from 10.6 m (pH) to 69 m (g ). In general, there was a high degree of randomness in plant available nutrients in this field, particularly at distances less than 5 m. The usefulness of this information in site-specific fertilizer application is discussed.
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