【作者】 朱琳；

【导师】 李世清；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2015， 博士

【摘要】 提高产量和资源利用效率是我国玉米栽培的新主题,玉米是我国重要谷类粮食作物之一,种植面积和总产量仅次于水稻,居第二位,而单位面积产量却居谷类作物首位。我国虽然是世界玉米生产第二大国,但我国玉米单产与世界其他发达国家相比仍处于中等水平。为此,在不增加施肥量的同时挖掘现有玉米品种的产量潜力,不断提高籽粒产量和氮肥利用效率是目前玉米生产中的主攻目标。我们通过4年工作已构建了适宜于黄土高原旱地的春玉米高产高效栽培体系,但该体系是否具有足够的理论基础,除从栽培体系、水氮管理及其与气候耦合关系等揭示其理论基础外,还需从植株同化产物/养分累积、转移及源库关系等作物本身揭示。为回答这一问题,本研究提出的基本科学推理是“与一般农户栽培模式相比,高产高效栽培体系植株除在生育后期维持较强同化能力外,源部同化产物及养分向库的转移量及转移效率保持着较高水平”。本研究的主要目的是证明该推理是否成立,从理论上揭示所构建的黄土高原旱地春玉米高产高效栽培体系的可靠性,并对其赋予丰富的理论基础,为黄土高原旱地春玉米高产高效栽培提供可靠的理论依据。通过2~3年田间试验及实验室分析,获得以下主要研究结论:(1)随着生育时期推进,春玉米吸氮量持续增加,幼苗期到拔节期时增加缓慢,拔节期到开花期快速增加,然后增加速度放缓,到完熟期时达到最大。地表覆盖能够显著增加春玉米吸氮量,地膜覆盖增加效果最好,吸氮量为236kg/hm2~245kg/hm2,其次为覆砂,吸氮量为200kg/hm2~217kg/hm2。与不覆膜和覆砂相比,地膜覆盖能够增加各器官特别是促进叶和茎的吸氮量及转移量,但对转移率和转移氮素贡献率效果不显著。地膜覆盖对氮素利用率及氮素生理利用率显著不显著,但显著提高春玉米氮素收获指数及氮肥偏生产力,显著提高春玉米产量,达到13334kg/hm2~13707kg/hm2。(2)随着施氮量增加,春玉米植株吸氮量呈现增加趋势,当施氮量超过200kg/hm2~250kg/hm2时,植株吸氮量增加不显著。施氮量为200kg/hm2~250kg/hm2时,植株吸氮量为212kg/hm2~264kg/hm2。增加施氮量,能够增加叶、茎+叶鞘及籽粒氮素累积量。施氮量为250kg/hm2时,籽粒在完熟期时的氮素累积量为167kg/hm2~180kg/hm2,继续增加施氮量,效果不显著。增加施氮量可以显著提高营养器官向籽粒转移氮素量,但对营养器官转移氮素对籽粒吸氮量的贡献率及氮素转移率没有显著影响。增加施氮量还可以提高籽粒产量。施氮量为250kg/hm2时,籽粒产量最大,为13.7t/hm2~15.1t/hm2。氮素利用率、氮素生理利用率及氮肥偏生产力随着施氮量上升而显著下降。氮素收获指数受施氮量影响不显著。综上所述,较适宜的施氮量为200kg/hm2~250kg/hm2。(3)随着生育时期推进,春玉米吸氮量增加,增加趋势为先缓慢增加,接着快速增加,然后又缓慢增加,到达完熟期时达到最大。花后揭膜处理与生育期不揭膜处理对春玉米各器官氮素累积量、各器官氮素转移量及转移率、转移氮素贡献率、氮素收获指数、氮素利用率、氮素生理利用率影响不显著。花后揭膜处理与生育期不揭膜处理对春玉米植株吸氮量及籽粒产量影响不显著,但是花后揭膜处理提高了春玉米植株吸氮量,为272kg/hm2~320kg/hm2,提高了春玉米籽粒产量,为15669kg/hm2~17523kg/hm2。在春玉米后期,地膜覆盖效果不如揭膜处理。因此,在春玉米全生育期没有必要全程覆膜,花后揭膜效果更显著。(4)覆膜能够提高玉米灌层截获的太阳能辐射量及土壤有效积温量,同时提高玉米对土壤有效积温利用率,以扩大玉米干物质的“源”。同时,覆膜通过增加籽粒数、籽粒体积来扩大玉米自身库容,进而提高籽粒产量。(5)花后揭膜通过改善叶面积指数,提高穗位叶净光合速率、穗位叶SPAD值,扩大玉米生长“源”,同时通过提高单穗穗轴、苞叶及籽粒干物质重,单穗穗粒数及籽粒体积来扩大玉米库容。花后揭膜会促进玉米干物质量,特别是花后干物质累积,提高籽粒干物质同化量,进而提高籽粒产量。而花后揭膜对籽粒收获指数及籽粒干物质转移量没有显著影响。更多还原

【Abstract】 Increase of production and resource use efficiency is the new theme of maize cultivation.Maize as one of the important cereal crops in China,its cultivation area and production is in the second place following rice,whereas the yield per unit area of maize ranks first in cereal crops.Although China is the world’s second-largest country in maize production,the yields is still at a moderate level compared to developed countries.Therefore,exploration of yield potential and improvement of nitrogen use efficiency of current maize varieties with increasing the amount of fertilizer are main goals of our research.We had built a suitable Plateau of spring maize yield planting system in last four years,theoretical basis of that sufficient or not,which has to be supported by theoretical foundation from cultivation systems and water nitrogen management coupling to climate,in addition to the need to assimilate products from the plant/nutrient accumulation,transfer and source-sink relations.To answer this question,this study presents the basic scientific hypothesis that "compared with the general pattern of farmers planting,yield planting plants in addition to maintaining a strong system of assimilation in the late reproductive capacity,the source department assimilates and nutrients transferred to the sink and to maintain transfer efficiency at a high level." The main purpose of this study was to demonstrate that the reliability of this hypothesis,and to provide a reliable theoretical and practical basis to the constructed reveal Plateau of spring maize yield planting systems.By 2 to 3 years of field testing and laboratory analysis,the following main conclusions were obtained:(1)With the growth stages advance,spring corn N(Nitrogen)uptake increases continuously,during the seedling stage to jointing stage raises slowly while jointing stage to the flowering stage elevate rapidly,and the increase speed slow down again reaching a maximum point in the ripening period.Mulching can significantly increase the spring corn N uptake,which values are 236 kg / hm2 ~ 245 kg / hm2 by mulching and 200 kg / hm2 ~ 217 kg / hm2 by mulching.Compared to the bare and sand covering mulching can increase the N uptake in various organs and especially the promotion and transfer of leaves and stems,whereas the transfer rate and the transfer of nitrogen contribution rate effect are not significant.Mulching did not improve the nitrogen utilization efficiency significantly,however,nitrogen harvest index and nitrogen partial productivity in spring maize increase significantly,and also the yield reached 13334 kg / hm2 ~ 13707 kg / hm2.(2)With the increase of nitrogen supply,spring corn N uptake showing an increasing trend,while the amount of nitrogen supply exceeds 200 kg / hm2 ~ 250 kg / hm2,the plant nitrogen uptake increase was not significant.Nitrogen was 200 kg / hm2 ~ 250 kg / hm2,the plant N uptake was 212 kg / hm2 ~ 264 kg / hm2.Increase the amount of nitrogen can increase leaf,stem + leaf sheath and grain nitrogen accumulation.Nitrogen was 250 kg / hm2,the grain nitrogen accumulation in the ripening period is when 167 kg / hm2 ~ 180 kg / hm2,continue to increase the amount of nitrogen,the effect is not significant.Increase the amount of nitrogen can significantly improve the vegetative organs to grain nitrogen transfer amount,but no significant effect on the vegetative organs transfer of nitrogen on grain nitrogen uptake and nitrogen contribution rate transfer rate.Increase the amount of nitrogen may also increase grain yield.Nitrogen was 250 kg / hm2,the maximum grain yield,is 13.7t / hm2 ~ 15.1t / hm2.Nitrogen use efficiency,nitrogen use efficiency and nitrogen partial physiological productivity rises with the amount of nitrogen decreased significantly.Nitrogen harvest index is not affected by significant amounts of nitrogen.In conclusion,the more appropriate amount of nitrogen was 200 kg / hm2 ~ 250 kg / hm2.(3)With the progress of growth stages,spring corn N uptake increases,an increasing trend for slow increase first,followed by a rapid increase,and then slowly increase the time to reach the maximum ripening period.Removing membrane after flowering growth stage without removing film processing and handling of various organs of spring corn nitrogen accumulation,transfer the amount of nitrogen in different organs and transfer rate,the contribution rate of transfer of nitrogen,nitrogen harvest index,nitrogen utilization,nitrogen physiological efficiency had no significant effect.Removing film after flowering growth stage without removing film processing and handling of spring corn N uptake and grain yield was not significant,but after flowering,removing film treatment increased the spring maize N uptake,was 272 kg / hm2 ~ 320 kg / hm2,increase the grain yield of spring corn,for 15669 kg / hm2 ~ 17523 kg / hm2.In the late spring corn,removing membrane was as effective as mulching.Thus,in the spring maize growth period is not necessary to the whole film,removing membrane effect more pronounced after flowering.Meanwhile,the mulching increases the corn grain volume to expand their storage capacity,thereby increasing grain yield.(5)Removing membrane after flowering through improving leaf area index,ear leaf SPAD value,expand the corn grow,"source",while a single spike by increasing the cob,husk leaves and grain dry weight,single spike grain number and grain volume to expand corn storage capacity.After flowering removing film will promote corn dry weight,dry matter accumulation especially after flowering,increased grain dry matter assimilation,thereby increasing grain yield.And after flowering,removing film had no significant effect on the grain harvest index and grain dry transfer amount.更多还原