减氮增密对杂交糯高粱籽粒产量和干物质生产的影响

Effects of Nitrogen Reduction and Densification on Grain Yieldand Dry Matter Production of Hybrid Waxy Sorghum

为探讨减氮增密对高粱光合作用、干物质积累与转运特征及产量的影响,2017-2018年选用杂交糯高粱品种晋渝糯3号为供试材料,大田试验,设置常氮常密(CK)、常氮增密(T1)、减氮常密(T2)、减氮增密(T3)4个处理,测定高粱抽穗期叶绿素含量(SPAD)和叶面积指数(LAI)、干物质积累与转运、产量及其构成因素。结果表明,与CK相比,减施氮肥降低抽穗期高粱顶三叶的SPAD和LAI,增加密度虽然降低顶三叶的SPAD,却能显著提高LAI。随生育进程的推进,高粱群体干物质积累量呈递增趋势,拔节期后迅速增加,成熟期积累最大。减少施氮量,提高高粱叶和茎鞘的花前干物质转运率及其转运量对籽粒的贡献率,但降低群体干物质积累量和花后干物质积累量及其对籽粒的贡献率。增加密度显著提高高粱群体干物质积累量、叶和茎鞘花前干物质的转运量、转运率及对籽粒的贡献率,但显著降低了花后干物质对籽粒的贡献率。增加密度,降低单穗质量和千粒质量,但显著增加高粱籽粒产量。减氮处理降低高粱单穗质量和千粒质量,但减氮下常密产量下降,增密产量却显著增加。与CK相比,T1和T3处理2 a平均产量分别显著增加8.43%和7.92%,但两处理间无显著性差异。因此,晋渝糯3号在重庆地区宜采用减氮增密模式种植,即施氮150 kg/hm^(2),密度12.75万株/hm^(2),有利于实现高粱的高产高效和节氮栽培。

In order to elucidate the effect of decreasing nitrogen rate and increasing planting density on photosynthesis,dry matter accumulation and transportation characteristics and yield of sorghum,a field experiment was conducted using the waxy sorghum hybrid Jinyunuo 3 as experimental material in 2017-2018.Four treatments of normal nitrogen application with normal planting density(CK),normal nitrogen application with dense planting density(T1),reducing nitrogen application with normal planting density(T2),and reducing nitrogen application with dense planting density(T3)were set to investigate the chlorophyll content(SPAD)and leaf area index(LAI)at heading stage,dry matter accumulation and transport characteristics,yield and yield components of sorghum.The results showed that,compared with CK,the SPAD of the top three leaves at heading stage and LAI were decreased by reducing nitrogen application,while the SPAD was decreased by dense planting,but LAI was increased significantly.The dry matter accumulation of sorghum population increased with the development of growth process and increased rapidly after jointing stage and reached the maximum in maturity stage.Reducing nitrogen application improved dry matter translocation efficiency of leaf and stem+sheath before anthesis and contribution to grain,but decreased dry matter accumulation of population,dry matter accumulation after anthesis and its contribution to grain.Increasing density significantly boosted dry matter accumulation of population,dry matter translocation of leaf and stem+sheath before anthesis,as well as their transportation efficiency and contribution to grain,but reduced the contribution of dry matter to grain after anthesis.The ear weight and 1000-grain weight were reduced by dense planting,but the yield increased significantly.The ear weight and 1000-grain weight were decreased by reducing nitrogen application,but the yield of normal density decreased while that of densification increased significantly.Compared with CK,the 2-year average yield of T1 and T3 treatments were significantly higher by 8.43%and 7.92%respectively,and there was no significant difference between the two treatments.In conclusion,the planting mode of Jinyunuo 3 in Chongqing was reducing nitrogen application with dense planting,that was,applying nitrogen 150 kg/ha and density 12.75×108 plants/ha.It was beneficial to realize high yield,high efficiency and nitrogen saving cultivation of sorghum.