Model For Growth,Yield And Quality Of Hydroponic Lettuce Based On N,P,K Concentration

NPK plant growth and development is the greatest impact of the three elements, and thus a reasonable allocation study plant nutrient solution is the key to build the model.Through regression analysis, quantitatively study the NPK three factors and their interactions on the relationship between the quality and yield formation of lettuce. In order to provides a theoretical guidance to achieve high quality and high yield of lettuce,the lettuce high-yield, high efficiency, high quality model and regression model was established to make the realization of the vegetable nutrient solution in the process of growth and development of intelligent control. The conclusion is as follows:(1) Basing on the multivariate regression model modeling principle, the yield of lettuce multiple quadratic non-linear regression equation was established.The correlation between lettuce yield and main agronomic traits is: r3(leaf width) > r2(leaf length) > r5(plant expansion) > r1(leaf number) > r4(plant height). Leaf length, leaf width, and plant expansion have the most closely relationship with yield.( 2) Lettuce yield regression mathematical model of three factors( NPK) was established, the model has been tested to reach significant level. Analysis and prediction can be revolved in. At later growth stage, when the concentration of NPK tendency for 4.65mmol/L, 0.69 mmol/L and 2.43 mmol/L respectively, the maximum yield can be reached. The order of three factors on the yield was N > P > K.;At the early stage of the growth of lettuce,the influence order of three factors on the yield of lettuce was N > K > P, when the concentration of NPK tendency for 8.46 mmol /L, 0.62 mmol /L and 2.57 mmol/L respectively, the highest yield can be reached.(3)The nitrogen is the main factor of nitrate accumulation, nitrate content increased with the increase of nitrogen concentration; When phosphorus in a certain stage, nitrate content decreased with the decrease of nitrogen concentration. When nitrogen in a certain stage, with the phosphorus increased,nitrate content concentration showed a trend of decline after rising first, but the increase is not obvious. When the phosphorus in a certain stage,nitrate content decreased with the increase of potassium concentration. When concentration of potassium in the middle level, nitrate content declined with the increase of nitrogenconcentration; When potassium concentration in the intermediate level or above, nitrate content showed a trend of decline after rising first with the increase of nitrogen concentration.The NPK combined application to VC content of lettuce is not obvious. Fertilizing NPK respectively, VC content proves the form of opening downward parabola. When the content of NPK were 6.36, 0.61, 3.97 mg/L, vitamin C content is up to 480.17 mg/kg.