In order to evaluate the effects of gravel mulching in arid and semi-humid regions of China on soil water
storage，crop growth，crop yield and water use efficiency，based on the measured data of summer corn grown at Yangling
in 2014 and the meteorological data，evapotranspiration of the reference crop was calculated at various growth stages by adopting
the formula of Penman － Monteith． The actual crop evapotranspiration was calculated by adopting the formula of
field water balance equation，then the variation of the crop coefficient of different growing periods was analyzed，as well as
the water use efficiency under different mulching levels． The results showed that gravel mulching could maintain water at
the beginning of crop growth by 12． 8%，reaching the maximum at the jointing stage，and then became decreased because
of canopy． A linear relationship between gravel degree and crop coefficient was found． The larger the amount of coverage，
the higher the increases of the corresponding crop coefficients at different growing stages． Leaf area and plant height had
good regression relationships with crop coefficient，and thus corn evapotranspiration can be forecasted during the growth period．
Gravel mulching made the growing period shortened，reaching a the maximum of nineteen days． Gravel mulching
also preserved soil moisture better，and reduced soil evaporation，increased soil water storage and water retention
capacity，thereby increasing crop water use efficiency and yield by 4． 65% ～ 38． 17% and 2． 94% ～ 32． 00%，respectively． The effects became enhanced when the mulching coverage was increased extensively within the extent of
this research．
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