Study on the spatial distribution of the content of potassium in the upper stream of the Hunhe River basin, Northeastern China

摘要

Continuous soil nutrient data is the basic data of soil information system, soil nutrient spatial interpolation study becomes very important because it can affect the data reliability of soil nutrient data straightly. Kriging was used for analysing the spatial variability of soil K content in the upper stream of the Hunhe River basin, Liaoning Province which covers 53% of the total area of Qingyuan County, by employing geostatistical methods and GIS technique. The topsoil samples were collected at 217 locations in cropland or forest land. The results show that soil total K and available K are strongly spatially dependent, followed a normal distribution, with an arithmetic mean of 1.83%, 88.00 mg/kg and median of 1.82%, 79.52 mg/kg. Semivariograms showes that both the soil total K and available contents had strong spatial dependency, which might be attributed to intrinsic and extrinsic factors. The soil available K contents were the highest in secondary forest soils and lowest in non-irrigated farmland soils. The experimental variogram of soil K content has been fitted with an exponential model. Map of the soil K content was generated through interpolation of measured values by ordinary kriging.