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 -7.518...