Establish Of Lettuce Hydroponics Nutrient Solution Formula Model And Design Of Expert System

By means of quadratic general rotational design under the conditions of Veroponic Hydroponics.the comprehensive effects of the concentrations of N, P, K, CaandMgon lettuce yield was studied.With the aid of computer,the model demonstrationg the ralationships between yield factor(y) and five element factors the concentrations of N, P, K, Ca and Mg ( xl -X2, X3, X4, xs) were established.The model is as follow:Y=106.01839+5.09917*, +3.64083 X2 +4.41583 X3 +2.17417X4 -4.45591 xf -7.51841 x22 -3.60591 x\ -2.23091 x] -2.90591 x] -3.47625 xl X2 +3.96125 x, *4 +2.97375 X3 X5Analysis result showed that: firstly, the effects of five factors on the yield of lettuce increased by degrees in series of magnesium (Mg), calcium (Ca), phosphorus (P), Potassium (K.) and nitrogen (N). Secondly, the interaction among five factors existed. The interaction between N and K % N and P were significant;There is significant positive interaction between them in lower level and significant negative interaction between them in higher level. Thirdly,by simulation with computer,to achieve the individual plant yield of 111.44g,the optimal combination of these factors was obtained, that is to say, the application amount of the concentrations of N^ P, K^ Ca and Mg could be 285.21 mg ?/', 35.25 mg ?L/1, 350.06 mg ?I/1, 228.71 mg ?L'1 and 66.04 mg ?I/1.In the verification experimention with treat AN B> C-. D and CK,the root vigor> photosynthesis> transpiration and yield of the lettuce that planted with the optimal nutrient formula from the model were superior to CK, and it with the baddish nutrient formula from the model was inferior to CK,that prove the model is accuracy and reliability.In order to improve management level of soilless culture, based on the model, the expert system of lettuce soilless culture was designed. The system adopted three layers calculate system of Browser/Server/Database, and could be running in internet. It contain eight module viz. nutrient solution manage, greenhouse biuld and manage, before seeding preparative, field planting, field manage, harvest manage, prevention and cure of the lettuce diseases ang insect pests, prevention and cure of the lettuce physiology obstacle.The system based on the model of examination and more scientific and reliability.But by the limited of time* labour power and found,it require improving and prompting, and now it is only to supply references to biuld other expert system.