冬小麦抗逆栽培技术原理的研究 Ⅱ不同生育期重施氮肥对冬小麦生育和抗逆性的影响

本文通过不同生育期重肥N肥对小麦器官建成、光合产物分配与籽粒蛋白质含量等的影响,明确了造成小麦贪青、倒伏的“危险施肥期”和施用N肥的“最大效益期”,并对如何防止贪青、倒伏,增强抗逆性,提高产量和品质等安全、经济施用N肥的技术问题进行了初步探讨.结果表明:1.冬小麦生育前期(注1)施N过多,是造成田间群体大、基部节间长、成穗率低、穗小粒少、千粒重低、生育延迟等的主要原因.因而生育前期是引起冬小麦贪青、晚熟和倒伏的“危险施肥时期”,也叫“N素的过剩敏感期”.2.冬小麦生育前期不施N或者底施N“不过量” 时,生育中、后期重施N肥不仅不会引起贪青、倒伏,而且能大大提高小麦后期的光合生产率和抗逆性,达到成穗率高、小穗退化少和提高粒重的明显效果,使抽穗后的干物质生产量达到籽粒产量的90%左右,尤其是春五叶露尖的中期施肥(即拔节肥)可明显提高小麦产量.因此,拔节期是冬小麦的“N素最大效益期”,也叫“N素不足敏感期”,也是冬小麦抗逆栽培技术中的安全、经济施肥期.

THE STUDIES ON THE PRINCIPLES OF STRESS RESISTANCE TECHNIQUES OF WINTER WHEAT CULTIVATION II. The Effect of Heavy Application of N-fertilizer in the Different Growth Stages on the Growth and Stress Resistance of winter wheat

A study of the effect of excessive nitrogen application during different growing stages on the growth and stress resistance of winter wheat was conducted from 1984 to 1985. The results are as follow:1. Excessive application of N fertilizer during the early growing stage of winter wheat is the main cause for large field population, long basal interno-des, low heading percentage, small size of ears and grains, low 1000-grain weight and retardation of growth.Therefore, the early growing stage is "the critical period of fertilization" ( or "the sensitive period of N excess" ,which may cause late-ripening and lodging.2.Both non-application of N or proper application of basal N during the early-growing stage, and heavy application of N during the middle and late growing stages do not cause late ripening and lodging.They can increase the efficiency of photosynthesis,stress resistance and heading percentage, and raise grain weight and dry matter production to 90% of the total seed production. Therefore, the jointing period either can be called "the maximum efficiency period of N" or "the sensitive period of N defficiency" , which is the safe and economical period of fertilization.