Effects Of Different Nutrient Solution Potassium Concentrations In Nutrient Solution And Three-dimensional Dislocation Cultivation On The Growth And Yield Of Hydroponics Lettuce

Leafy vegetables are one of the main vegetables grown in my country’s facilities,and their consumption is huge.In order to further tap the potential of leafy vegetables to increase production and improve the efficiency of water and fertilizer use,In this experiment,the ’Flandre’lettuce variety was used as the test material,starting from the optimization of the three-dimensional dislocation cultivation structure and the regulation of the potassium concentration of the nutrient solution,two experiments were carried out:Experiment 1 set 5 nutrient solution potassium concentrations to explore different nutrient solution potassium The effect of concentration on the growth,quality,nutrient solution consumption and nutrient solution utilization efficiency of hydroponic lettuce,the water and nutrient absorption of lettuce,and the gas exchange parameters of lettuce leaves;Experiment 2 was based on optimizing the potassium concentration of nutrient solution and according to the height of the cultivation rack and spacing hydroponic tank is provided six different three-dimensional structures dislocation cultivation,cultivation explored different perspective lettuce dislocation growth,yield,and canopy net photosynthetic rate of radiation,to achieve efficient production of lettuce provide a scientific basis.The specific experimental research results are as follows:1.The effect of potassium concentration in different nutrient solutions on hydroponic lettuceThe dry and fresh weight of the root and cap and leaf area of lettuce showed a trend of first increasing and then decreasing with the increase of potassium concentration.The growth indexes of lettuce treated with T4 were the best,and the potassium concentration of nutrient solution was too low or too high to inhibit it.Lettuce grows.The potassium concentration of the nutrient solution has little effect on the root to shoot ratio(fresh weight),leaf SPAD value,and lettuce moisture content;it has no obvious effect on the lettuce Vc content and nitrate content.Under the condition of low potassium concentration in the nutrient solution,an appropriate increase in the potassium concentration is conducive to the absorption of nitrogen,phosphorus,potassium,calcium and magnesium by lettuce plants,and also helps to improve the utilization efficiency of the nutrient solution,but excessive potassium concentration will inhibit the lettuce plants The absorption of nitrogen,phosphorus,potassium,calcium and magnesium reduces the utilization efficiency of nutrient solution.By establishing the relationship between the potassium concentration of the nutrient solution,the yield of the lettuce and the utilization efficiency of the nutrient solution,the optimal potassium concentration of the nutrient solution is 3.7mmol L-1,which can take into account the yield of lettuce and the utilization efficiency of the nutrient solution,and is suitable for efficient lettuce production.2.The influence of different three-dimensional dislocation cultivation structure on hydroponic lettuceThe leaf area,SPAD value,dry and fresh weight of crown and root,root-to-shoot ratio(fresh weight),middle and lower layer and total yield of W4 treatment were all larger than those of other treatments;the net photosynthetic rate of lettuce leaves was "double peak" type,in the morning,The net photosynthetic rate of the leaves of lettuce in W4 treatment was the highest.In the afternoon,the net photosynthetic rate of lettuce leaves was the highest in treatment W1;the total radiation and photosynthetic active radiation in the canopy of W4 treatment were the highest,and the accumulated photosynthetic active radiation in the day of the lettuce canopy was greater than the lowest.Under the premise of daily average light,lettuce yield is given priority,and the daily accumulated photosynthetically active radiation in W4 treatment is the best.Considering comprehensively,W4 treatment(the cultivation layer is 500mm from the ground,the cultivation layer spacing is 870mm,the middle hydroponic tank spacing is 950mm,and the lower hydroponic tank spacing is 150mm)the lettuce grows best,and the light environment conditions are the best.It is a suitable three-dimensional dislocation cultivation structure for lettuce cultivation.