一、试验目的在世界许多地方,由于水源不足,限制了农业的发展。在我国西北部地区年降雨量少,作物生长期的需水,主要靠人工灌溉。华北地区的水资源也不甚足,而且降雨受季风的影响,常有春早和伏旱。补充性灌溉已成为棉花稳产高产的关键措施。本试验在人为干旱条件下,研究棉花生育和产量的变化,以便把有限的水量用在棉 I. PURPOSE OF TEST In many parts of the world agricultural development has been limited due to the lack of water. In the northwestern part of our country, there is little annual rainfall, and crop water demand mainly depends on artificial irrigation. North China’s water resources are not enough, and the impact of monsoon rainfall, often early spring and drought. Supplementary irrigation has become a key measure of cotton yield. This experiment under artificial drought conditions, the study of cotton growth and yield changes in order to limit the amount of water used in cotton