Study On Processing Tomato Mulched With Plastic Film Under Regulated Deficit Drip Irrigation

In this research, 9 treatments of soil water deficit were designed to explore the effect of regulated deficit irrigation on the soil moisture, water consumption, the indicators of growth, yield and water use efficiency of processing tomato with drip irrigation. The results showed that:1. During the whole growth period ,The trends performance of water consumption of processing tomato showed decreases at first, then increases and decreases at last. the treatments with water deficit showed the water consumption was lower than the control, and increased rapidly after recovering water, even more than the control. The rate of Water consumption of processing tomato declined compared with the control at the water deficit stage, and declined more obvious with more degree of deficit. the leaves of aging rate of processing tomato was declined by water deficit at later growth stage, which led to water consumption rate of processing tomato was higher than the control at the later growth stage, and water consumption modulus was lower at the water deficit stage than other treatments, and water consumption modulus of severe deficit treatments was lower than the rest phases of this treatments and other treatments.2. Plant height, stem diameter and leaf area index of processing tomato grew fast at the flowering and fruiting period, and tended to be stable after fruiting flourishing period, leaf area index showed a decreased trend after fruiting flourishing period. Dry matter accumulation of processing tomato was few at the seedling period, which increased rapidly at the flowering and fruiting period, then tended to be sustained increase with the pressing of growth period, and reached maximum at the last fruiting period.3. With different water deficit treatments, the overall performance of the soil temperature of each layer was 5cm> 10cm> 15cm> 20cm> 25cm, which has a distinct feature of diurnal variation. Diurnal variation rate was greatly between 5cm to 15cm, which changed slowly from 20cm to 25cm.stage differences occurred for each treatments.4. Under the condition of drip irrigation with regulated deficit, the exerted of water stress in the seeding stage of F2 and F1 treatments, of which the irrigation water use efficiency reached maximum, was 61.46kg/m~3 and 51.77kg/m~3 respectively. Followed were F8 and F7 treatments with being exerted water stress in later fruiting period, was 49.30kg/m~3 and 45.43kg/m~3 respectively. treatments F4 and F3 with being exerted water stress in the flowering and fruiting period, of which the water use efficiency was lowest, was 30.41kg/m~3 and 31.10kg/m~3 respectively. Water use efficiency of treatments F2 with being exerted water stress at seedling stage was the highest(35.48kg/m~3), the followed was CK treatments with plenty water supply(30.71 kg/m~3), and treatments F3 with being exerted water stress in the flowering and fruiting period was the lowest(23.74 kg/m~3).5. The irrigation amount of the treatments CK (with plenty water supply ) was the largest but the yield was not the highest. While the treatments F2 with slight water deficit at seedling stage,the irrigation amount was low but yield was the highest, reached 2025m~3/hm~2 and 124458.31kg/hm~2 respectively, the proportion of water conservation was 35.71% compare with the control treatments. Meanwhile, the treatments of F2 have the highest net income, reached 30729.99 RMB per hectare. Overall, the efficiency of slight water deficit at seedling stage was the best.6. By using the Blank model and the Jensen model, that the maximum sensitivity index of processing tomato was the flowering and fruiting stage, which means the effect of water shortage on yield was most critical at the stage of flowering and fruiting, While the sensitivity index was the minimal at the seedling and later fruiting stage, which showed that the effect of water shortage on yield was not significantly.