土壤的结构形态,叫土体构型,是整个土体的各个层次的排列组合关系,把土壤作为一个整体,不仅耕作层有重要作用,同时其下各层对整个土壤肥力也有重要影响。

North China Plain is an alluvial plain. The alluvium are alternatingly deposit. In-vestigation shows that the soluni structure patterns of North China Plain are very complex and diversified. The interstratified solum pattern and the loam (apposite) solum pattern are much fertile than the clay solum pattern, dispersed sandy solum pattern and sandy gravel solum pattern.There is a close relationship between the solum structure patterns and the growth of crops. The differences in function and effect of the solum patterns depend on the presence or absence of the barried-layer in the soil profile of 0-100 cm. When there is no such layer, the supply of water and fertilizer will be higher and crops yield is ge-nerally high and stable.The barrier layer or barrier factors in solum of farm-land of North China Plain include thin cultivated horizon, hard plowpan, lower content of waterstable aggregate, hard calcic horizon, alkali-saline soil and pollute etc. All these are unfavorable to the growth of crops.