Abstract:

【Objective】Nitrogen management and irrigation model of greenhouse tomato were studied. 【Method】 Four treatments, control (CK), conventional nitrogen (CN),optimized nitrogen (ON) and recommended nitrogen (RN) management treatments were designed to investigate tomato yield, N application rate, loss of N, the agronomic efficiency of chemical N fertilizer and irrigation water. 【Result】 Tomato yield of CK reached a higher level although any chemical N fertilizer was not used, the phenomenon of yield reduction appeared with the increasing of the rate of N sidedressed in winter-spring season. The rate of N sidedressed of CN is 600 kgN?hm-2, and the irrigation water is about 7 500 m3?hm-2, there are 1 416 kgN?hm-2 has been lossed as the result of the unreasonably water and N management; Compared with CN, the loss sidedressed N and the loss of total N decreased by 50% and 32.2% in RN; The rate of N sidedressed of ON is 314 and 124 kgN?hm-2 in two seasons respectively, and the irrigation water is 3 900 and 4 550 m3?hm-2, with the total loss of N reduced by 38.6%. The agronomic efficiency of chemical N fertilizer in CN, ON and RN treatments in the whole year is 0, 24.9 and 0.3 kgFW?kg-1N, respectively. Tha agronomic efficiencies of irrigation water of the conventional and optimized irrigation treatments are 12.2 and 23.2 kgFW?m-3, respectively. The ON can reduce 4 000 yuan/hm2 by decreasing N fertilizer and irrigation water input. 【Conclusion】 The rate of N sidedressed is not the leading factor restricting the increase of tomato yield. Water and N management mothods of optimizing N sidedressing and irrigation by employing bubbler irrigation system during the growing season, and applying calcium cyanamide mixed with wheat straw in summer-fallow are considered as the better water and N management.

Key words: greenhouse tomato, nitrogen management, irrigation methods, wheat straw, calcium cyanamide, yield, agronomic efficiency