Spatial variability of Agricultural fields

Thus, descriptive statistics indicated the size able spatial variability for all soil variables. Further understanding of the spatial structures of soil variables can be helpful for revealing their spatial distribution and achieving the reasonable site specific farming management. The geo-statistical analysis of soil variables suggested that the value nugget-sill ratio ranges from 0% (EC) to 55.22% (Av P), except for available sulfur(72.21%), indicating that internal factors were dominant over external factors. Soil EC and OM had the strong spatial dependence with a nugget-sill ratio of < 25%, because it induced by structural factors. But the spatial variability of other soil variables (pH, TN, Av P, Av K & Av S) had the moderate spatial dependence with a nugget-sill ratio of 25-75%, because the variables were mainly determined by internal and external factors.These results are reflection of many factors including soil pH, CEC, OC, amount of moisture held by soil particles, fertilizer application, animal manure application with different amendments, intensive cropping system, different land use pattern, topography of the field at different weather condition and texture percentage.