区域农田土壤质地剖面的随机模拟模型

STOCHASTIC SIMULATING MODELS FOR SOIL TEXTURAL PROFILES OF REGIONAL FIELD

冲积土壤剖面的质地层次分异是该类土壤的重要特性，对农田水分转化和溶质运移具有重要影响。要准确地定量农田水转化和溶质运移，定量模拟区域冲积土壤质地剖面是十分必要的。本文依据已取得的研究结果，采用Markov链理论提出了区域冲积土壤质地层次的随机模拟模型——MC模型和MC－LN模型，采用蒙特卡罗方法模拟了研究区的土壤质地剖面，并与实测结果进行了对比。结果表明，两模型模拟结果均很好地反映出了区域土壤剖面质地层次的垂向变化规律，但在质地层次厚度的分布上，MC模型结果偏差较大，而MCLN模型模拟结果与实测结果颇为一致。

The spatial change of textural layers is one of the impotant features of alluvial soils. It affects soil water transport and solute movement in field intensely. But the quantitative studies on it are limited. Based on the results obtained in our research,this paper presented tWo stochastic models-MC (Markov chain) model and MCLN (Markov chain--Lognormal distribution) model for simulating textural profiles of regional alluvial soils using Markov chain theory, and simulated soil textural profiles by Monte Carlo method. Results showed that the vertical changes of textural layers along soil profiles in the research region could be reflected by this tWo models. But in the probability distribution of textural layer thickness, MC model often brought on more error, and MC-LN model was in accord with the measured data. Considering the far more intensive effects of number and sequence of textural layers in profiles than the error of textural layer thickness on field warer and solute movement. two models would be accepted simultaneously.