| Spatial scale is forefront in soil-scientific research, so the analysis of macropore reasonable sampling size becomes significant which is in case of taking account of spatial variability.This paper based on the soil microscopic structure,progress quantify study on macropore under different circumstances, with technique of the analyzing image and numerical picture system.Connect with classical statistical theory and geostatistic theory to discuss the distribution and reasonable sampling size.Main work are as follows:(1) The quantify description of macropore characters showed that the change trend of macropore numbers was almost conform among distinct diameter ranges. At first, it is lightly fluctuat until 135 mm, from 200mm it began smooth. The macropore degree achieve a peak of 26.4% at 155mm and met the minimum 3% 280mm, until 450mm it reached second peak of 48.2%.(2) Classical statistical analysis showed that macropore degree showed medium intensity variation.Coefficient of variation is from 46.7% to 69.4%. Pc mainly concentrated from 2.58 to 3.122, C s mainly concentrated from 0.1 to 0.168. The macropore of the soil was take on normal distribution.(3) Geostatistics analysis showed that macropore degree mainly changed between 199.1mm and 206.7mm in less than 20mm space,but 25mm and30mm changed in a larger way.With increase of minimum distance lag, model testing parameters increased from 0.0025 to 0.0051,simulate accuracy reduce,reason- -able sampling interval is about 20 mm;Various diameter sampling analysis showed that variable distance changed steadily in 25mm and 40mm,but rate is very large.Meanwhile rate of 60 mm or more scale changed between 89.44mm ~ 97.70mm,relatively stable, structure is very strong.numberof I decreased from 0.00243 to 0.0044,variogram calculation and simulation accuracy are increasingly high,reasonable diameter is within 80 to100 mm area.This paper mainly studied sampling size of macropore,it laid scientific direction of research on macropore flow. |
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