DPC调控棉花氮素追肥时期的复合效应研究

STUDIES ON THE COMPLEX RESPONSE OF APPLYING NITROGEN AT DIFFERENT STAGE UNDER DPC CONTROL

1986～1988年,选用陆地棉(Gossypium hisrsutum L.)农大7631、北农1号和中棉12号品种,在大田栽培和应用植物生长延缓剂 DPC(1.1-二甲基哌啶(钅翁)氯化物,编节安)调控条件下,分别于蕾期、初花期和盛花期进行 N 素追肥处理(每亩施纯氮6～7.5kg,其中2/3用作基肥,1/3用于追肥),进行了 DPC 系统化控与 N 素追肥时期相结合的复合效应研究。试验结果表明:(1)在 DPC 调控下,前二期、特别是蕾期施氮肥,较盛花期施用有较强的提高根系活力的作用,表现为根系伤流量增加,伤流液中的可溶性糖、还原糖、氨基酸和无机磷的总量提高,以及根系合成细胞分裂素能力增强。(2)DPC 调控早施氮肥可以协调棉株生育前期的营养生长与生殖生长,在棉株发育的中后期,可以改善棉铃的时空分布,并对棉铃和纤维细胞的发育有促进作用。(3)三年试验选用三个品种,经历了不同气候条件,DPC 化控早施氮肥对产量均无不良影响,尤其是在棉花主要生育期间降雨多日照少的年份,化控早施氮肥对产量的形成和增加霜前花比率更为有利。这表明在 DPC 调控下将传统的重施花铃肥的时间提早到盛蕾期或初花期施用是有益的和可行的,同时还表明追施氮肥的施用时期可以有较大的主动性和灵活性,这对于提高施肥的经济效益和劳动效率也都很有意义。

During 1986-1988,under the conditions of DPC application in the field,the complex response of applying nitrogen at square,early-flowering or full- flowering stage was studied with three cultivars.The results showed that:(1)Com- pared with applying nitrogen at full-flowering stage,applying nitrogen early, especially at square stage,the root activity of cotton plants was increased,e.g., root bleeding sap,the amounts of soluble sugar,induced sugar,amino acids,inor- ganic phosphorus and cytokinnins in root bleeding sap were all increased.(2)Apply- ing nitrogen early could keep the balance between vegetive growth and reproductive growth,and improve boll setting,as well as promote the development of boll and fibre.(3)Applying Nitrogen early did not have negative effects on cotton yield, and increased the percentage of cotton yield harvested before frost in the year of too much rainfall and little sunlight during cotton growth stage.This result showed that changing traditional way of applying nitrogen at full flowering stage to square or early flowering stage was possible and beneficial,and there were more activity and flexibility of applying nitrogen.To apply nitrogen early is also beneficial toraising. labour efficiency and getting more profit.