Admittedly, agricultural prices have all external factors. Such as inevitable scourge lead to agricultural production, the so-called "content with rare for expensive" rare natural its price is high. Another such as prices generally rises planting higher costs, caused the agricultural product also had to on price rising over the and so on. However, any product prices have a "degree". It should not be the irrational and limit prices at random, also should not be far beyond the product itself contains the value, more should not serious from current market demand and people's consumption level. If excessive beyond, is the "and is not caused by man-made" cut teasing of the scourge .