The Effects Of Irrigation Amount And The Water And Nitrogen Application Of Drip Irrigation System On The Growth And Development Of Tomato

The production of vegetable in greenhouse plays an important role in the development of rural economy, improving the income of farmers and people’s lives. At present, the phenomenon of blind irrigation and fertilization is widespread in the production of vegetable, resulting in the decline of vegetable crop production and quality, the waste of water and fertilizer resources and the deterioration of soil etc. With the development of water-saving irrigation technology, drip irrigation with high yield and good quality is gradually introduced into the greenhouse production, but how to scientifically reasonable use these irrigation technologies still lacks systematic and deep research. This experiment was conducted in the greenhouse at Yangling, Shaanxi, to study the influence on the growths of tomato under diffirent water and nitrogen management and provide a scientific foundation for high yield and quality cultivation.The main conclusions are as follows:1. The variation trend of plant height, stem diameter and leaf area under different water and nitrogen management is the same: with the increasing of irrigation water, plant height, stem diameter and leaf area has the rising trend. The plant height, stem diameter, leaf area in the whole growth has the regularity of "s" curve. The crop logistic curve model has a good simulation on tomato morphology growth trend across the growth period. The chlorophyll content of tomato leaf showed the trend of first increased and then decreased as the promote of growth period.2. The root length under S1 strategy is higher than under S2 strategy, but the surface area, diameter, volume and dry weight of root were less than the S2 strategy. Almost all tomato root were mainly concentrated in the 0 ~ 30 cm soil layer. With the deeper of soil depth, the ratio of soil root length was decreasing. The equation y=Aexp(-Kx) can well fit the variation of tomato root length in soil depth under different water and nitrogen management; Using principal component analysis method to analysis root length, surface area, volume, dry weight and average root diameter by mathematical statistics. The results show that, W-N-W operation mode with middle water(W2) treatment had the best effect on root regulation.3. Under N-W mode the yield increased with the improving of irrigation amount. Under W-N-W operation mode the yield was first increased and then decreased with the improving of irrigation amount. Under the same operating conditions, the water use efficiency was decreased with the increase of irrigation amount. Under the same irrigation amount, W-N-W operation mode has a higher water use efficiency than that of N-W. Under N-W operation mode, fruit weight, root weight and dry matter weight increased with the increase of irrigation amount. Under W-N-W operation mode, fruit weight, root weight and dry matter weight were first increased and then decreased with the increase of irrigation amount. As stem and leaf, the dry weight of stem and leaf increased with the increasing of irrigation amount, and the dry weight of stem and leaf had no significant difference under the same water amount.4. The soluble solid content and soluble sugar content were decreased with the increasing of irrigation amount. VC, nitrate, tomato red element and the organic acid were first increased and then decreased with the increasing of irrigation amount. Nitrate and vitamin C showed a very significant positive correlation, organic acid and nitrate has a significant positive correlation, ratio of sugar to acid and soluble sugar showde a extremely significant positive correlation. Using principal component analysis method on the tomato quality under different water and nitrogen management for comprehensive evaluation, the results show that, N-W operation mode with middle water(W2) was the best treatment.5. The content of nitrate nitrogen decreased rapidly after irrigation in 1-5d, 5-7d tended to decline. After drip irrigation, centered below the drop head, the moisture content has a ladder distribution from the emitter. The content of soil nitrogen decreased obviously near the drop head, soil nitrogen accumulate at 20 cm away from the emitter. Under the same operation mode, with the increasing of irrigation amount, the accumulation of nitrate nitrogen in 0-20 cm soil layer decreased gradually, while increased in 40-60 cm soil layer. Across whole irrigation process, the operation mode of W-N-W can better retained the nutrients in the crop root layer, reduce the leaching loss of nitrogen. N-W operation mode with middle(W2) water has the best nitrogen utilization rate.