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通过水稻田间氮施肥用量试验,氮肥对水稻的增产效果非常明显,最高增产幅度达86.9%。水稻在整个生育过程中叶绿素含量的生理变化特征是:返青期完成后,进入分蘖期,叶绿素含量达到最高点,随着生育进程的推进叶绿素含量逐步降低,灌浆期后叶绿素含量急剧下降,成熟后期降至最低点;生产上一般以前两次追施氮肥最为重要,如果第一次追施氮后SPAD值不足44,第二次追施氮量应适当加大,如果SPAD值超过46,第二次追施氮量应适当减少,第二次追施氮肥后SPAD值不足47时,应考虑在7月中旬适当补追施一定量的穗肥,如果SPAD值超过47,可以免追穗肥。
Through the nitrogen fertilization experiment in paddy field, the effect of nitrogen fertilizer on rice yield is very obvious, with the highest increase rate of 86.9%. The physiological characteristics of chlorophyll content during the whole growth period of rice were as follows: After the greening stage was completed, the chlorophyll content reached the highest point at the tillering stage. With the gradual decrease of chlorophyll content during the growth stage, the chlorophyll content decreased sharply after the grain filling stage, To the lowest point; the production of the last two topdressing nitrogen fertilizer is most important. If the SPAD value after the first topdressing of nitrogen is less than 44, the second topdressing nitrogen should be appropriately increased. If the SPAD value exceeds 46, the second When the SPAD value of the second topdressing nitrogen fertilizer is less than 47, a certain amount of spike fertilizer should be properly replenished in the middle of July. If the SPAD value exceeds 47, it can be avoided.