不同生态区高粱籽粒产量和品质对氮肥施用的响应

Response of sorghum grain yield and quality to nitrogen application in different ecozones

研究不同生态区高粱产量和品质对氮肥施用的响应,分析生态区影响高粱产量形成机制,对高粱产区优化和促进高粱产业发展具有重要意义。本研究以11个高粱品种为研究材料,于2020和2021年在山西朔州和晋中开展田间试验,研究2个生态区高粱抽穗期和收获期的干物质量和氮素积累量、籽粒产量和产量构成以及籽粒品质对氮的响应,分析高粱籽粒产量形成与物质积累的关系。结果表明:除2021年不施氮(即连续2年不施氮)处理外,其他处理朔州试验点高粱产量高于晋中,施氮和不施氮处理平均增产幅度分别为8.6%~26.7%和13.8%。氮肥施用降低千粒重,但提高了高粱穗粒数,穗粒数对产量的相对贡献率达97%;同一施氮条件下朔州试验点穗粒数显著高于晋中。整体来看2个试验点抽穗期干物质和氮素积累量分别高达收获期的51.93%和68.86%,且抽穗期干物质量和氮素积累量与籽粒产量均呈显著的一元二次回归关系,表明提高抽穗期干物质积累对高粱产量形成至关重要;而不施氮时,抽穗后干物质量形成也显著影响籽粒产量。与晋中试验点相比,朔州试验点抽穗期干物质和氮素积累量分别增加40.17%~61.47%和15.72%~47.03%,而抽穗后干物质和氮素积累量小于晋中试验点,这说明朔州试验点较高产量的形成与抽穗期干物质和氮素积累量密切相关。此外,除连续2年不施氮处理外,朔州试验点高粱籽粒淀粉和单宁含量高于晋中试验点,但蛋白质含量相对较低。昼夜温差不同可能是导致2个生态区产量品质差异的重要原因。综上可知,朔州冷凉区高粱产量显著高于晋中温暖半湿润区,提高高粱抽穗前干物质和氮素积累量对籽粒产量形成十分关键,冷凉区较大的昼夜温差有利于抽穗前干物质和氮素积累,促进籽粒产量提高。

Identifying the response of sorghum grain yield and quality to nitrogen application in different ecozones can enhance the understanding of the yield formation process,help improve sorghum productivity,and promote the development of the sor-ghum industry.This experiment was conducted in Shuozhou and Jinzhong of Shanxi province in 2020 and 2021 in the field.Both no nitrogen and nitrogen fertilizer application were included,with 11 sorghum varieties in each nitrogen application plot.The dry matter and nitrogen accumulation both at heading and harvest stages,grain yield and its components,and grain quality were in-vestigated.The relationships between grain yield and biomass at heading and harvest stages were also studied,respectively.Re-sults showed that the average sorghum grain yield in Shuozhuo was greater than that in Jinzhong,except for the no nitrogen treatment in 2021(i.e.no nitrogen applied for two consecutive years).Compared with the yield in Jinzhong experimental sites,grain yield in Shuozhou increased by 8.6%–26.7%when nitrogen was applied in 2020 and 2021,and 13.8%without nitrogen application in 2020,respectively.Nitrogen application decreased 1000-grain weight but improved significantly grains per parti-cle.Grains per particle exerted great influence on grain yield,and contributed 97%to the yield variation.The grains per particle in Shuozhou was higher than in Jinzhong for the same nitrogen treatment.For both experimental sites,dry matter and nitrogen ac-cumulation at heading stage occupied 51.93%and 68.86%of that at harvest stage,respectively.Substrate accumulation at heading stage had significant quadratic regression relationships with sorghum grain yield.This suggested that it was important to improve dry matter and nitrogen accumulation at heading stage for higher sorghum grain yield.Meanwhile,when nitrogen was withdrawn,the grain yield was more closely correlated with dry matter accumulation after heading stage.Compared with Jinzhong experi-mental site,the dry matter and nitrogen accumulation at heading stage increased by 40.17%–61.47%and 15.72%–47.03%in Shuozhou,respectively.But the regression relationships between their accumulations,from heading to mature stage,and grain yield of Shuozhou were relative low.The enhanced grain yield in Shuozhou,compared with that in Jinzhong,was closely corre-lated with the improved accumulations of dry matter and nitrogen at heading stage.The contents of both starch and tannin were also higher in Shuozhou,and protein was lower relative to Jinzhong,except for the treatment of no nitrogen applied for two con-secutive years.The large daily temperature difference of Shuozhou might accountfor its promoted yield and quality.The variation in terms of grain yield and quality between two ecozones was resulted from difference diurnal temperature range.Obviously,sor-ghum grain yield in high latitude and cold area(Shuozhou)was higher than that in warm sub-humid area(Jinzhong).Promoted dry matter and nitrogen accumulation before heading was crucial to achieve high sorghum yield.The larger temperature difference be-tween day and night in high latitude and cold area was conducive to substrate accumulation before heading and improve grain yield.