SPATIAL VARIABILITY AND GEOSTATISTICAL ANALYSIS OF SOIL REACTION, ELECTRICAL CONDUCTIVITY AND ORGANIC MATTER CONTENT
Spatial variability of soil parameters is important for refining agricultural management practices and has a crucial efforts to introduce sustainable agricultural systems. Soil properties change in time and places, even spatial structure of soil variables change in various geographic directions. The study was conducted on Keshabpur upazila at Jessore district in Bangladesh to analyze the spatial variations of soil pH, electrical conductivity and organic matter content and to predict the degree of spatial variability for those properties by applying kriging technique and semivariogram modelling. Soil pH, EC and OM content ranged from minimum 6.95 to 8.60, 0.24 to 2.27 dSm−1 and 1.03 to 2.81% respectably. The coefficient variation was the lowest for soil pH (5.88 %) and the highest for EC (69.32 %) among the studied soil properties while CV of SOM was 26.01 % respectively. High and significant correlations between soil pH, EC and OM content was found. Soil pH, EC and OM follow a random spatial distribution and clear patchy distribution all over the studied area as the percent nugget value includes 100%, 90.92% and 79.18% respectively and the spatial variability of estimating soil properties varies within range of 0.1591 for pH, 0.1203 for EC and 0.0671 for SOM and this model can calculate the unsampled within neighboring distance of about 10.00m for pH, 56.60m for EC and 149.06m for SOM respectively. Higher pH value found in the south east site and gradually decreasing with distance to North regions. EC of the soil was higher in the south east where there has a scope of small amount of littoral deposition of estuarial intrusion of brackish tidal water from river through creeks and possess slightly saline soil. Soil degradation increased with soil tillage and rapidly deteriorated soil fertility by decreasing OM. Therefore, a sustainable soil management system should be applied to decrease soil degradation.