Study on Grading Standards for Field Investigation of Frost Damage to Winter Wheat
Zhao Tianhong · Mailei zuowu xuebao · 2011
Frost damage of winter wheat is a main meteorological disaster for winter wheat production in North China.For the field monitoring of this meteorological disaster on winter wheat and evaluating its severity,informative grading criteria for classifying the frost damage on winter wheat would be established.In this study,based on the field tracking investigation to winter wheat,the practical experiences of investigating and assessing the meteorological and agricultural data and the morphological characteristics of freezing-suffered wheat,the grading criteria of frost damage to winter were established with 5 grades of no frost damage,mild frost damage,moderate frost damage,severe frost damage and serious frost damage.The characters of each grade were as followed.The wheat suffered from mild frost damage appeared that a few of leaves were frostbitten,parts of them could resume growth and the yield reduction rate was about 5%.The wheat suffered from moderate frost damage appeared that some leaves of wheat were frostbitten,the growths of those parts were difficult to restore and the yield reduction rate was by 5%~30%.The wheat suffered from severe frost damage appeared that most leaves of plants leaf canopy were frostbitten,the growth of this part could not be restored and the yield reduction rate was by 30% to 50%.The wheat suffered from extraordinarily severe frost injury appeared that a large number of leaves were frostbitten,the leave tips were dry a few days later and the yield reduction rate was more than 50%.This grading standards established on the damage of frost on wheat,which would provide a guide for agricultural workers to accurately evaluate the severity of frozen damage and pave the way for producers to adopt scientific and effective remedy measures to reduce losses.