Thinking up solutions Chang thought endlessly on the problems of how to create economies of scale and how to standardize farming techniques. In 2002, he began using the October-February period when the paddies lie fallow to plant roots and tubers. He called the new technique the "halfback production system," and formed something akin to a strategic production and marketing alliance to promote it.
思路決定出路不斷思考如何擴大經濟規模、建立標準作業程序的張有擇，於 2002 年開始利用水稻田休養生息的「裡作」（10 月至次年 2 月）期間，種植根莖類蔬菜，建立一種類似產銷策略聯盟、稱之為「中衛生產體系」的作業方式。