| Plant factories are the product of the development of agricultural modernization,which can achieve annual crop production through the internal environmental regulation of the facility.Plant factories mainly produce leafy vegetables by hydroponics.The nutrient distribution ratio and concentration of the nutrient solution play a vital role in the yield and quality of leafy vegetables.Water spinach（Ipomoea aquatica Forssk.）is loved by people because of its rich nutrients and delicious taste.At present,the research on the nutrient solution of hydroponic leaf vegetables mainly focuses on lettuce,and there are few researches on the formula of the adaptive nutrient solution of water spinach.Therefore,this experiment carried out the effects of different nutrient solution formulations as well as nitrogen and potassium concentrations on the growth,yield and quality of hydroponic water spinach,in order to provide theoretical basis and technical support for the optimization of hydroponic water spinach nutrient solution under plant factory conditions.The main results are as follows:1.Comparing the effects on the quality and biomass dynamics of water spinach for 5 kinds of nutrient solution formulas,which are commol·L-1only used in hydroponics of leafy vegetables.Both used 1/2 concentration,they were Hoagland（CK）,Japanese garden experimental（T1）,Yamazaki Chrysanthemum（T2）,Copper（T3）and Dutch greenhouse（T4）formula.The results showed that compared with CK and other formulas,T2 treatment was more conducive to the growth and nutrient accumulation of water spinach.Moreover,the yield of water spinach for each plant under this formula increased by 24.1%compared with CK,while the nitrate content of leaves was significantly reduced.Therefore,this formula has the best effect on hydroponic cultivation for water spinach.2.According to the previous results,the influence of different nitrogen and potassium concentration on the growth and quality of water spinach were studied on the basis of the formula for yamazaki chrysanthemum.It was found that compared with the CK(6.7 mmol·L-1),reducing the nitrogen concentration appropriately could promote the accumulation of dry matter of water spinach and increase its yield.When the nitrogen concentration was 6.0mmol·L-1,the root vitality,photosynthetic pigment content and yield of water spinach were significantly higher than those of the CK and other treatments.Analyzing the indicators of growth,yield and cost of water spinach comprehensivly,the results showed that the concentration of 6.0 mmol·L-1 nitrogen was more suitable for water spinach cultivation.3.When the potassium concentration was increased within a certain range,the yield of water spinach increased firstly,and then decreased.When the potassium concentration is 4.8mmol·L-1,the yield of water spinach reached the highest level.In terms of quality,the Vc content of water spinach increased with the increment of potassium concentration.The content of soluble sugar,soluble protein and nitrate showed an increasing tendency,after that,it dropped.Furthermore,when the potassium concentration was 4.8 mmol·L-1,the overall quality of water spinach is optimal,and higher benefits for per plant and output-input-ratio could also be obtained.Therefore,a potassium concentration of 4.8 mmol·L-1 was more suitable for hydroponic water cultivation under plant factory conditions. |
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