The study is on community structure of spiders which is main predator in crop fields in North China,and distribution dynamics of dominant species in habitats of forest belt,crop field and ridge of field.

Soft-ridged bench terrace design in hilly loess region;

Vertical sliding surface of slope was anatomized,and used in stability and regression analysis of terrace embankments,numerical model has given that little land was occupied by terrace embankments,it is possible that the best design and practice apply in terrace embankments.

Based on that, rooting patterns of plants on the terrace embankments are classified.