过量施氮对西藏河谷农区青稞生长发育的影响

Effects of Excessive Nitrogen Application on the Growth and Development of Highland Barley in Tibet Valley Agricultural Area

摸清过量施氮下不同青稞品种(系)生长发育指标的变化和调控机制,为西藏河谷农区青稞高产高效栽培提供科学依据。本研究设置N_(1)(施氮量70 kg/hm^(2),常规施氮处理)、N_(2)(施氮量172.5 kg/hm^(2))、N_(3)(施氮量275 kg/hm^(2))、N_(4)(施氮量345 kg/hm^(2))4个施氮处理,CK(施氮量0 kg/hm^(2))为不施氮处理,比较分析不同施氮量水平下,青稞品种‘藏青3000’和青稞品系‘6927’的株高、分蘖和成穗、叶绿素、粒重和籽粒灌浆特性、氮素利用和产量等因子的变化。结果表明,施氮对青稞的基本苗没有影响,青稞分蘖率呈现出先增加后降低的趋势,相同处理下‘6927’的最高茎蘖数高于‘藏青3000’;随着施氮量的增加,青稞成穗数呈现减少的趋势;随着施氮量的增加,所有生育期的株高均表现为先升高后降低或增加不明显的趋势;随着施氮量的增加,叶绿素SPAD值呈先增加后不再显著增加或降低的趋势,‘藏青3000’各施氮处理的旗叶叶绿素SPAD值高于‘6927’;施氮可明显提高青稞各生育期粒重,粒重在开花后7~28 d时增高趋势十分明显,于花后35 d达到最大值,常规施氮的实际粒重和理论最大千粒重均高于其他处理,本研究2个青稞品种(系)最大灌浆速率(V_(max))和平均灌浆速率(V_(mean))均出现在N_(2)处理;青稞的产量随着施氮量的增加呈现出减少的趋势,相同处理下‘藏青3000’产量均高于‘6927’;氮肥农学利用率和氮肥偏生产力均随着施氮量的增加而降低。

To find out the change and regulation mechanism of growth and development indexes of different highland barley varieties under excessive nitrogen application,providing scientific foundations for high-yield and high efficiency cultivation of highland barley in the Tibet river valley,five fertilization treatments were set in this study,including N_(1)(70 kg/hm^(2) of nitrogen,conventional nitrogen application treatment),N_(2)(172.5 kg/hm^(2) of nitrogen),N_(3)(275 kg/hm^(2) of nitrogen),N_(4)(275 kg/hm^(2) of nitrogen)and CK(0 kg/hm^(2) of nitrogen),to compare and analyze the variations of plant height,tiller and spike rate,chlorophyll,grain filling,nitrogen utilization and yield of the highland barley varieties‘Zangqing 3000’and‘6927’under different nitrogen application levels.The results showed that there was no significant difference on the basic seedlings in different treatments,the variation of tillering rate increased first and then decreased.The tiller number of‘6927’was higher than that of‘Zangqing 3000’under the same treatment;the number of spike decreased with the increase of nitrogen application;the plant height increased first and then decreased or no significant difference in growth stage with the increasing of nitrogen application rate;the chlorophyll SPAD increased first and then kept stable or decreased significantly with the increase of nitrogen application rate;the chlorophyll SPAD of‘Zangqing 3000’was higher than that of‘6927’under the same treatment;nitrogen application could increase the grain weight significantly in each growth period,the grain weight increased significantly from 7 to 28 days after flowering date,reached the maximum value on 35th days after flowering.The actual grain weight and theoretical maximum of thousand-grain weight of conventional nitrogen application were higher than that of other treatments.In this study,the maximum grouting rate(V_(max))and average grouting rate(V_(mean))of two highland barley varieties(lines)were in N_(2) treatment;the yield of highland barley decreased with the increase of nitrogen application,and the yield of‘Zangqing 3000’was higher than that of‘6927’under the same treatment;the nitrogen agronomic efficiency and nitrogen partial factor productivity decreased with the increasing of nitrogen application rate.