Greenhouse tomato experiment was conducted in Shouguang

Shandong province in order to investigate the effects of different water and nitrogen strategies on fruit yield and soil inorganic nitrogen of greenhouse tomato.Compared with conventional water and nitrogen management(CWN)

optimize water and nitrogen management(OWN) is real-time control of rootzone N management and related target values were used to optimize N sidedressing

and irrigation up to field capacity by employing with bubbler irrigation system during the growing season

and applied for Calcium Cyanamide mixed with wheat straw in summer-fallow

Recommended water and nitrogen management(RWN) is sidedressed 100 kg/hm2 at the duration of first

third and fifth fruit ear enlargement separately.The result showed that there were no significant differences on tomato fruit yield of the OWN and RWN with 36.5% and 50% of sidedressed N input in comparison with conventional water and nitrogen management during two season greenhouse tomato system

in addition

the OWN decreased the irrigation water by 44% and 39% in two growing seasons

but the fruit yield increased by 10% significantly.Conventional nitrogen input made the content of soil inorganic nitrogen kept in a high level during the tomato growing season;The residue of soil inorganic nitrogen above 200 kg/hm2 in every layer and the total residue of soil inorganic nitrogen more than 1500 kg/hm2 in 0-180 cm soil depth after harvesting.The residue of soil inorganic nitrogen is 1/2 of CWN after the OWN and RWN improved the water and nitrogen management

significantly reduced the risk of nitrogen leaching and the effects of unreasonable water and nitrogen management on environment.