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砀山是我国四大棚菜生产示范基地之一。近几年来．随着保护地的发展．保护地内肥害问题愈来愈重．1988年1000公顷大棚黄瓜．其中90%以上的田块都不同程度地发生黄瓜氨气和亚硝酸危害，造成严重的经济损失。其危害及防治方法为：一、危害症状1．氨过周幼苗叶片褪色．叶缘呈烧焦
Dangshan is one of the four demonstration bases for greenhouse vegetable production in China. In recent years. With the development of protected areas. Protected land increasingly fatter problem. 1988 1,000 hectares of greenhouse cucumbers. More than 90% of the plots are harmful to the ammonia and nitrite of cucumber to varying degrees, causing serious economic losses. The harm and prevention methods are as follows: First, endanger the symptoms 1. Ammonia peridous seedling leaves fade. Leaf edge was charred