چکیده:
The main objective in the present study was to assess the spatial variation of chemical and physical soil properties
and then use this information to select an appropriate area to install a pasture rehabilitation experiment in the
Zereshkin region, Iran. A regular 250 m grid was used for collecting a total of 150 soil samples (from 985
georeferenced soil pits) at 0 to 30, and 30 to 60 cm layers. Soil samples were analyzed for pH, EC, N, K, P, Na, Ca,
Mg and SAR. Conventional statistical methods and geostatistics were performed in order to analyze soil properties
spatial dependence. Mean, standard deviation, skewness, and kurtosis for all measured variables were evaluated. All
variograms generally were well structured with a relatively large nugget effect. Soil properties such as pH, P
semivariograms were best fitted by spherical models, while SAR, Na were best fitted by spherical models. In the
beginning kriging were performed in order to analyze spatial variation of chemical and physical soil properties, then
for enhancing estimation accuracy and comparing results we used cokriging technique. Comparison of the results using
statistical techniques showed that kriging technique has acceptable accuracy in characterizing the spatial variability. Also
results showed that although kriging technique has acceptable accuracy in characterizing the spatial variability of soil
properties but if higher accuracy is needed, cokriging is preferred to kriging particularly when the extra variable has been
used.
خلاصه ماشینی:
Student, Faculty of Natural Resources, University of Tehran, Karaj, Iran c MSc. Graduate, Faculty of Natural Resources, University of Tehran, Karaj, Iran d Faculty member, Hormozgan University, Bandar Abbas, Iran Received: 17 September 2007; Received in revised form: 20 March 2008; Accepted: 16 September 2008 Abstract The main objective in the present study was to assess the spatial variation of chemical and physical soil properties and then use this information to select an appropriate area to install a pasture rehabilitation experiment in the Zereshkin region, Iran.
In the beginning kriging were performed in order to analyze spatial variation of chemical and physical soil properties, then for enhancing estimation accuracy and comparing results we used cokriging technique.
These techniques have provided the means to characterize and quantify spatial variation have been used to process this information for rational interpolation, and have been applied to estimate the variance of interpolated values (Isaaks and Srivastava, 1989; McBratney and Pringle, 1999; Webster, 2000; Gaston et al.
Stark et al (2004) estimated small scale spatial variability of selected soil biological properties by using geostatistics methods.
Our main objective in the present study was to assess the ability of kriging and cokriging techniques to predict spatial variation of chemical and physical some of the soil properties such as texture, gravel, hardness and organic mater in selected soil samples from Zereshkin area in north of Iran, Mazanderan province.