نوع مقاله : مقاله پژوهشی
نویسندگان
1 استاد دانشگاه
2 دانشجوی سابق کارشناسی ارشد دانشگاه بوعلی سینا، همدان
3 استادیار پژوهش، موسسه تحقیقات خاک و آب، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران
4 استاد دانشگاه بوعلی سینا، همدان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Soil saturated hydraulic conductivity (Ks) is one of the most important soil physical properties. Its direct measurements is difficult, expensive, and time consuming because of spatial and temporal variability. Therefore, pedotransfer functions have been used to estimate Ks. The purpose of this study was to improve the estimation of Ks using fractal parameters of particle and micro-aggregate size distributions and to compare their efficiency with the structural parameters at six stages in the estimation of Ks. As a matter of fact, one pedotransfer function was developed in each stage with different input variables. In this study, 260 soil samples were taken from different parts of Guilan province, Iran. Particle and micro-aggregate size distributions (0-2 mm) were measured and fractal model of Bird and Perrier (2003) was fitted to them and their parameters were calculated. Significant correlations (P < 0.01) were found between Ks and fractal parameters of particles and micro-aggregates. Estimation of Ks was improved and root mean square error (RMSE) decreased significantly by using fractal parameters of soil particles and micro-aggregates as predictors. Using geometric mean diameters of soil aggregates at the stage four improved Ks estimations significantly, but, using geometric mean and standard deviation of soil particles at the stage five did not improve Ks estimations significantly. Using fractal parameters of particles and micro-aggregates, simultaneously, at the stage six, decreased RMSE considerably and had the highest effect on the estimation of Ks. Generally, fractal parameters may be successfully used as input parameters to improve the estimates of Ks by the pedotransfer functions.
کلیدواژهها [English]
62. Zhang, B. and Horn, R. 2001. Mechanisms of aggregate stabilization in Ultisols from subtropical China. Geoderma 99: 123