关键词: 双黄连口服液, 双黄连口服液, 正交试验, 制备工艺

Abstract: Abstract: Trend of soil nutrient and soil nutrient restriction factors of three crops were studied through testing the soil nutrient content and adopting the principle of least nutrient during the rotation period of summer maize→peanut-winter wheat. The result showed that in the Jidong Sand Rejion the line of trend of effective-N and effective-P was a trough form, but a complete wave form of effective-K; in the sand soil, effective-N and effective-K were common soil nutrient restriction factors of the three crops. On the base of this conclusion, the effective applying fertilizer method was forward: the nitrogenous and potash fertilizer was enough during summer maize period, but phosphate fertilizer may not apply; the count of potash fertilizer was increased , the count of nitrogenous fertilizer was stabilized and phosphate may apply few during peanut period; during the winter wheat period, this three fertilizers were took account of, but the nitrogenous and potash fertilizer was important .