小麦播种出苗后,由于受自然条件和栽培措施的影响,往往会形成各种不正常的异色苗。为便于因苗、对症管理,现分别介绍如下:黄叶苗麦叶黄化的原因:一是土壤干旱。这种情况多发生于底墒不足或透风跑墒的麦田。其特点是:分蘖出生慢,叶色灰绿,心叶短小,生长缓慢或停滞(一般称之为“缩心苗”),中下部叶片逐渐变黄干枯,根少而细。管理要点:结合浇水,每亩追施碳铵15千克。二是缺氮。幼苗细弱呈直立状,分蘖减少,叶片窄短。下部叶片从叶尖开始,逐渐变黄干枯,并向上部叶片发展。管理要点:每亩用尿素7~8千克,或碳铵20~25千克,或 After sowing wheat seedlings, due to the natural conditions and cultivation measures, often will form a variety of abnormal color seedlings. In order to facilitate due to Miao, symptomatic management, are introduced as follows: Yellow leaf seedling wheat yellow causes: First, soil drought. Occurred at the end of this situation is less than the amount of soil moisture or run moisture in the wheat fields. Its characteristics are: the slow-growing tillers, gray-green leaves, heart short leaves, slow growth or stagnation (generally referred to as “shrinking seedling”), the lower part of the leaves gradually turn yellow, thin roots and thin. Management points: combined with watering, topdressing ammonium 15 kg per acre. Second, nitrogen deficiency. Thin seedlings erect, tillers reduced, leaves narrow. The lower leaves start from the tip, gradually turn yellow and dry, and the development of the upper leaves. Management points: urea per acre 7 to 8 kg, or ammonium bicarbonate 20 to 25 kg, or