Based on the fact of the formation of large-scale soil dry layers in recent years

a field soil column up to 10 m was established to simulate the drying soil in jujube forests at the Mizhi experimental station

which is located in the north of Shaanxi Province. The purpose was to explore the regularities of rainfall infiltration and water migration

also to clarify the infiltration capability of dry loess. By using the CS650-CR1000 automatic system

changes of soil moisture within different depths were observed continuously under natural conditions. Meanwhile

the precipitation during the monitoring period was recorded by an automatic weather station. The results showed that both of the depths of infiltration and migration under independent rainfall mainly depended on the precipitation. The depth could reach up to 90-140 cm

70-80 cm

and 40 cm

respectively

when influenced by heavy rain

middle rain

and light rain. With the same precipitation

it was affected by other factors such as rainfall intensity and initial soil water content. The greater the rainfall intensity and the higher the initial soil water content was

the deeper the depth was. Under intermittent rainfall conditions

several rainfall events promoted infiltration and migration interactively. Compared with independent rainfall

the intermittent rainfall could significantly increase the infiltration depth by 100-160%

and the migration depth by 91%-197% with the same precipitation. In the loess region

not all the rainfall events could influence the soil. During the observation periods

the effectiveness of the rainfall frequency and amount were 36.3%

72.7% respectively. Under the influence of multiple rainfall events

the soil profile tended to be layered. According to the changes of soil moisture

the affected soil could be mainly divided into three levels

i.e. the sensitive layer of rainfall infiltration within 90 cm

the delayed layer of rainfall infiltration between 90 cm and 160 cm

and the migrating layer of rainfall between 160 cm and 240 cm. The results are of great theoretical and practical significance to the restoration of woodland drying soil and scientific management of soil moisture in the loess hilly region.