The primary season of nitrate leaching in the Loess Plateau region is the monsoon,which is caused by heavy rainfall during
the growth season of corn ( Zea mays L.) abstract Nitrate leaching to groundwater is an increasing concern in agriculture,and is one of the major nitrogen losing ways in dryland farming system.Localized compaction and ridge
fertilization is a method for nitrogen fertilizer application,by which,less fertilizer leaching would occur.The NO_3 --N
transport in soil profile,corn yields and nitrogen use efficiency under localized compaction and ridge fertilization were investigated through two years field study.The factors that affect NO_3 --N transport under localized compaction and ridge fertilization were studied,combined with simulated experiment. The results showed that NO_3 --N was leached to below 90cm in plat fertilization in the year of about 370mm rainfall,a mean precipitation during the season,while the NO_3 --N leakage of the fertilizer zone was reduced by localized compaction and ridge fertilization,as a result that the NO_3 --N concentration below 60cm was less than 10mg·kg -1 ,and NO_3 --N accumulated in 20～40cm with a concentration 80～90 mg·kg -1 . There was no significant difference in yield between application methods with 240.0kgN·hm -2 . However,the absorbed amount of nitrogen was improved significantly by localized compaction and ridge fertilization,and the nitrogen use efficiency was increased by 9%. The bulk density of the barriers had an evident effect on NO_3 --N transport under localized compaction and ridge fertilization,but the effect of ridge slope was insignificant.