Geospatial assessment and mapping of soil properties of horticultural farm

This study was carried out to evaluate the heterogeneity of selected soil quality properties in surface and subsurface soil layers in an agricultural farm under tuber crops cultivation and to determine the correlation between these soil properties. A total of 260 soil samples were collected in March 2011 from agricultural farm of Central Tuber Crops Research Institute (CTCRI), Thiruvananthapuram, Kerala, India. The samples were collected from 0–15 and 1530 cm soil depths and each sampling locations was noted using a global positioning system. The collected samples were analyzed for soil moisture per cent, soil colour, turbidity ratio, soil pH, organic matter and labile carbon. After data normalization, descriptive statistical analysis of the data was carried out. Correlation between different parameters was analyzed. The spatial analysis was done using geostatistical analyst extension of ArcGIS 10.0 software. Spatial distributions of soil physico-chemical properties in the farm were estimated using kriging interpolation. The results showed that soils were generally acidic in pH. About 55% samples were yellowish red in colour. Among soil properties studied, very high variability was noticed in case of lability of carbon, followed by turbidity ratio and the lowest variation was observed for soil pH and labile carbon. Gaussian and exponential models fitted well with the experimental semivariograms of most of the soil properties. The nugget to sill ratios, which gives the degree of spatial dependence, was observed to be weak to strong for the soil properties. The kriged interpolation maps of the soil properties can be used as very good tools for farm planning at regional scale.