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一、缺氮的症状与防治(一)症状氮素营养是草坪植物生长发育的限制因素之一,如果氮营养不足,植物地上部和根系生长会受到显著抑制,缺氮对叶片发育的影响最大,会导致叶片细小直立,与茎的夹角小,叶色淡绿,严重时呈黄色。失绿的叶片色泽均一,一般不出现斑点或花斑。缺氮症状通常先从老叶开始,老叶较快地变黄或提早脱落,逐渐扩展到上部幼叶。缺氮的植株生长矮小,分枝或分蘖减少,植株容易早熟,对于收籽植物来说,种子小而不饱满,显著影响种子的产量和品质,缺氮时根量少,且生长后期停止伸长,呈现褐色。(二)施肥防治氮肥品种很多,大致可分为铵态、硝态、酰胺态和长效氮肥4种类型,各种氮肥的性质在土壤中的转化和施用,既有其共同之处,也各具有特点。现归纳介绍各类氮肥的共同性质及施用。
I. Symptoms and Prevention of Nitrogen Deficiency (I) Symptoms Nitrogen nutrition is one of the limiting factors for the growth and development of turfgrass. If the nitrogen is undernourished, the growth of plant shoots and roots will be significantly inhibited, and nitrogen deficiency has the greatest impact on the development of the leaves , Will lead to small and erect leaves, and the angle between the stems small, light green leaves, when serious yellow. Green leaf color uniformity, generally do not appear spots or piebald. Nitrogen deficiency symptoms usually begin with the old leaves, the old leaves turn yellow sooner or earlier, gradually expanding to the upper leaves. The nitrogen-deficient plants have short growth, fewer branches or tillers, and the plants are easy to get premature. For the seed-receiving plants, the seeds are small and not full, which significantly affects the yield and quality of the seeds. When the nitrogen is deficient, the amount of roots is small and the growth stops Long, brown. (B) fertilization prevention and control of many varieties of nitrogen, can be divided into ammonium, nitrate, amide and long-acting nitrogen four types, the nature of various nitrogen in the soil conversion and application, both in common, but also Each has its own characteristics. Now introduce the common nature of all types of nitrogen fertilizer and application.