To understand the output of agricultural crops that depend on natural conditions. If seasonal rains have produced a price slump last year, which the rain does not fall in season and disaster. There is a little output prices are very wrong with industrial products, which can be controlled to produce at any time.
To understand that agricultural productivity depends on nature. The seasonal rains have produced very low prices are what year did not rain season, and disaster will yield less well against products which can be produced at any time.
To understand that the crop agriculture depends on the state of nature. If the rain season will be produced, the price will decline, years in which no rain season and disaster. มีผลผลิต less, the price is good.