1974年冬种后不久,即出现麦苗大面积反黄。据白泉公社、金星、万强两个大队,在12月中旬调查,黄苗面积已达64%,发生期之早,发生面积之大,为历史上罕见年。为弄清大麦早期黄苗的发生原因及其防治,我们对黄苗的发生发展,进行试验观察和分析,现简述如下:黄苗的症状黄苗一般可分为两种类型:一种是黄叶斑点型,先在麦株下部第一叶上端出现针头大小的黄褐色的坏死斑点,直接破坏输导组织阻碍了无机盐类和光合产物运转,致使叶片上端发 Shortly after the winter of 1974 species, wheat seedlings that appear large area of ​​anti-yellow. According to the White Springs Commune, Venus, Wanqiang two brigade in mid-December survey, Huangmiao area has reached 64%, the occurrence of early, the occurrence of large area, a rare in history. To understand the causes of barley early emergence and prevention and treatment of barley, we develop the occurrence of yellow seedlings, the experimental observation and analysis are as follows: The symptoms of yellow seedlings Yellow seedlings can generally be divided into two types: one is Yellow leaf spot type, first in the lower part of the first leaf of wheat appeared needle size of the brown necrotic spots directly destroy the conduction tissue impede the operation of inorganic salts and photosynthetic products, resulting in leaves on the hair