| Water shortage and environmental pollution led by over-fertilization had become a serious constraint to the development of contemporary agriculture, How to allocate the limited water and fertilizer resources rationally to increase crop yield, quality and resource use efficiency were the most important things need to be solved in china's agricultural development. This study carried in the greenhouse of Beijing Academy of Agriculture and Forestry at 2007—2009, taking cucumber (Cucumis sativus L.) crops as a research object. The researches used a negative pressure water control technique to controll different soil mositure by adjusting the water supply tension of the irrigation device, the cucumber growth, yield, quality and their physiological mechanism were studied under different WSTs, fertilizations and water and fertilizer coupling, in order to provide a theoretical and practical basis for the high quality, high yield and high-performance of cucumber cultivations. The study`s results were as follow:1,To study the influences of soil moisture conditions on growth and development of greenhouse cucumber, negative pressure water supplying and controlling pot devices were used in the experiment to control different soil moisture by setting different water supply tension (WST) for the devices. Seven WSTs were set up in the experiment, i.e., 1, 3, 5, 7, 9, 11 and 13 kPa. The experiment results showed that the experiment device can maintain soil water content in an enactment state by setting the WST. WST and soil water content had an inverse correlation. Plant growing had a significant difference under different WSTs. The leaf photosynthetic rate, biomass accumulation as well as yield and marketable fruit rate of cucumber were much higher at 35 kPa WST treatments, and the range of WST from 35 kPa are more suitable for greenhouse cucumber growth when the relative soil water content ranges from 67% to 81 %. The highest root weight and activity appeared at 7 kPa when the relative soil water content was 54.58%. However, controlling the same soil moisture in whole growth period can`t increase WUE of cucumber significantly. There are no significantly effects on fruit water content, specific gravity and average fruit weight under different soil water content, higher soil water content lead to the decrease of fruit peel pigment, but the fruit soluble solids, Vitamin C, organic acid content, nitrate content increased and tannin content, sugar-acid ratio and free amino acids decreased under higher WST. The oluble protein content and sugar-acid ratio of cucumber fruits increased and nitrate content decreased under lower WST. The results indicated that he range of WST from 35 kPa were more suitable for greenhouse cucumber growth and fruit quality improvement when the relative soil water content ranges from 54.58 %66.61 %.2,Different fertilizer combinations and fertilizations levels experiment results showed that the N600P300K300 kg·hm-2 fertilization levels had a significantly positive effects on plant height, total leaves area, total dry mass accumulation and yield, but leaf photosynthesis and yield quality were lower than other fertilization levels, specifically manifested on the higher content of nitrate, tannin and organic acids, while the total sugar, soluble protein, Vitamin C and free amino acid content of fruit were low. There are no significantly difference on plant height and total leaves area under N300P150K150 kg·hm-2 and the 1800 kg·hm-2 of compound fertilizer fertilization, but leaf photosynthesis were higher than other treatments. And plant growth speed and yield were very low under 22500 kg·hm-2 fertilization of organic manure, but fruit quality was higher than other treatments. There are no significantly positive effects on plant growth and yield with adding the organic manure fertilizer at the N600P300K300 kg·hm-2 fertilization, but it could improve some fruit quality indexes values. However, There are had a significantly positive effects on plant growth and yield with adding the organic manure fertilizer at the N300P150K150 kg·hm-2 fertilization, and also it couldn improve the fruit quality at different harvest period. The above results showed that the mixed of N300P150K150 kg·hm-2and 22500 kg·hm-2 of organic manure fertilization were more suitable for the high yield and quality of cucumber cultivation in greenhouse.3,Water and nitrogen fertilizer coupling experiment results showed that water and nitrogen fertilizer coupling had a significantly effects on the growth of cucumber plant. Increasing soil moisture can improve the growth speed, leaf photosynthesis, root activity and dry mass accumulation of cucumber plant. The upground and underground dry mass weight increased with the increasinge fertilization levels during the range of N900 kg·hm-2 fertilization levels, and the N1200 kg·hm-2 fertilization levels had a negative effect on cucumber plant growth. The fertilization levels had a positive relationship with leaf SPAD value, but decreasing the soil moisture could increase the leaf SPAD value. If using leaf SPAD values to diagnose N fertilization of plant, need considering the factors of soil moisture. Increasing the nitrogen fertilization levels could improve the yield and WUE of cucumber under 4kPa WST, but the nitrate, tannin and organic acid content of fruit also increased, the fruit quality declined. However, the yield and WUE of cucumber will decrease if the nitrogen fertilization levels were above N900 kg·hm-2 under 8kPa WST. The soil nitrate content after harvest had a positive relationship with nitrogen fertilizer levels. The soil nitrate content under 4kPa WST was lower than 8kPa WST under the same nitrogen fertilizer levels. It's showed that increasing soil moisture could decrease soil nitrate content. The above results indicated that WST with 4kPa and fertilization levels with N900 kg·hm-2 coupling treatment and WST with 8kPa and fertilization levels with N600 kg·hm-2 coupling treatment was more suitable for the improvement of yield and quality of cucumber.4,Water and fertilizer coupling experiment results showed that water had a significantly positive effects on cucumber plant growth, dry mass accumulation and yield. The plant growth, leaf photosynthesis, root activity and root shoot ratio increased with the increasing of fertilization under 3 kPa and 5 kPa WST, but there are an opposition effect on high fertilization at 7 kPa WST. WUE increased with the increasing of fertilizations during the range of N900P450K450 kg·hm-2. There are no significantly effects on fruit length, diameter, water content and specific gravity under different treatments. The fruit quality would become bad at different harvest period under N1200P600K600 kg·hm-2 fertilization, while the nitrate and tannin content of fruit were higher and Vitamin C and soluble sugar content of fruit were lower. The fruit quality would increase if added the soil water content. It could increase Vitamin C and soluble sugar content of fruit and decrease nitrate and tannin content of fruit if decrease the soil moisture under N900P450K450 kg·hm-2 fertilization. There are a significantly effects on marketable rate, soluble proteins, free amino acids and soluble solids content of fruit under water and fertilizer couplings. The above results indicated that yield, dry mass accumulation, leaf photosynthesis, root activity and WUE were higher under 3kPa WST and fertilization levels with N1200P600K600 kg·hm-2 coupling treatment, but the fruit quality was lower than other treatments. The fruit quality will be better under 5kPa WST and fertilization levels with N900P450K450 kg·hm-2 coupling treatment.5,The different N ratio of base fertilizer and top dressing experiment results showed that the plant growth and development had a positive relationship with the N ratio of base fertilizer under the range of 80% for N ratio of base fertilizer, but the highest leaf photosynthesis appeared at 40% N ratio of base fertilizer treatment, followed by N60% treatment. The biggest upground dry mass and root dry weight appeared at N20% treatment, the highest yield of cucumber appeared at N60% treatment. The root activities under the range of N20%60% treatments were higher than other treatments. However the dry mass accumulation, yield and root activity of cucumber plant were very low under 0 % and 100% treatments. WUE of cucumber increased with the increasing N ratio of base fertilizer, the highest WUE value appeared at N100% treatment. Different N ratio of base fertilizer and top dressing had no significantly effects on fruit diameter, water content. The fruit marketable rate under N80% treatment was higher than other treatments, the nitrate and organic acids and Vitamin C content of cucumber under N60% treatment were lower than other treatments, while Vitamin C content of cucumber was higher. The N100% treatment fruit nitrate content was highest, but Vitamin C and soluble sugar content were lower than other treatments. NRA of cucumber leaves had a positive relationship with nitrate content of fruit. The above results indicated that the plant growth, leaves photosynthesis, root activity, dry mass accumulation, yield and fruit quality under the N ratio of base fertilizer range of 60%80% are more better than other treatments, and it could be used in the cucumber cultivation.6,Different concentrations of nitrogen solutions for potted cucumber results showed that the plant growth rate, dry mass weight and yield under 1? times of the Yamazaki concentration were higher than other treatments, the leaf photosynthesis was lower than the standard Yamazaki concentration treatment. Plant growth rate, dry mass weight and yield use the negative pressure water supply device were better than traditional irrigation method, which the yield increased 62.9%, but there are no significantly effect on nutrient solutions use efficiency. The fruit average weight, diameter, water content and specific gravity had no significant difference under different concentrations of nitrogen solutions and nitrogen solutions supply methods. Fruit length and marketable under ?S and 1S were higher than other treatments. Fruit nitrate and tannin content at different harvest period under higher concentrations of nitrogen solutions were higher than other treatments, including the soluble protein, Vitamin C, soluble sugar, and amino acid content of fruit. N, P element concentration in extractor solutions at the last growth period were significantly lower than the added nitrogen solutions, however, Ca, Mg and S and other elements there were a serious accumulation, indicated that the Yamazaki nutrient solution needs to be improved if using it in the cucumber medium cultivation, and it's better to increase the N and P concentration of nitrogen solutions and decrease the Ca, Mg and S concentration of nitrogen solutions, The above results indicated that negative nitrogen solutions supply and controlling method had a positive effect, the plant growth, yield and some fruit quality were better than traditional irrigation method, it's more suitable for the cucumber, the research results showed that taking regular EC value and mineral ions concentration monitoring of medium was a good way to know the plant consumption and the need for fertilizer, so as to guide the setting of different concentration of nutrient solution formulations.
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