Mathematical models of recommended fertilization of nitrogen, phosphorus and potassium for corn in com-soybean stereo-cultivation were set up by means of universal rotational combinatorial design and computer tcchnology. 10fertilization schemes bringing maxium production of corn and profit were selected separately. The fertilization amounts for maxium production are 50 kg/hm2 of urea, 1125 kg/hm2 of superphosphate and 332 kg/hm2 of potassium chloride, and N: P2O5 : K2O=1:0.39: 0.58. The fertilization amounts for maxium profit from corn production are 712.8 kg/hm2 of urea, 1125 kg/hm2 of superp...