Soil profile, soil moisture content (SMC), soil bulk density and soil water holding capacity both of in-using gravel-sand mulched field (GSMF) and abandoned GSMF in arid and semiarid area were determined to study soil profile structure and soil moisture characters of the GSMF. The effects of different gravel-sand mulching conditions on SMC were also studied through GSMF simulating experiment. The profile of GSMF has five layers, they are gravel-sand mixed layer, soil and gravel-sand mixed layer, roots dense layer, eluviating layer and calcium accumulation layer, respectively. Gravel-sand mulching can increase SMC significantly, and makes the eluviating layer deeper. The soil moisture condition in the GSMF which has full soil profile is better than in the GSMF which hasnt full soil profile. The SMC in upper soil layer is influenced significantly by deeper soil layer. The thickness of 9 cm and the small diameter of gravel-sand can help SMC accumulation. The SMC was the lowest in the first year after gravel-sand mulching, and then it increased slowly with the mulching duration increased. During the mulching year from the sixth to twelfth, the SMC reached the highest level, and then it decreased slowly with the mulching duration increased. When the mulching time is at the sixth year, the soil bulk density reached the lowest, and the water holding capacity reached the highest level, then with the gravel-sand mulching duration increased, the soil bulk density increased and the water holding capacity decreased slowly.

Soil profile of gravel-sand mulched field

Comparison of soil water content in simulated gravel-sand mulched field between different gravel-sand mulching method