【作者】 王志刚；

【导师】 高聚林；

【作者基本信息】 内蒙古农业大学 ， 作物栽培学与耕作学， 2009， 博士

【摘要】 内蒙古平原灌区是我国玉米高产潜力最大的地区,玉米超高产纪录不断刷新;目前限制产量进一步提高的主要问题:一是小面积上的高产纪录重演性差,在大面积上难以实现,且高产纪录突破难度不断增加;二是高产优势区水资源短缺,且水资源利用效率不高。问题的实质是玉米实现超高产的机理和超高产条件下水分高效利用途径不明确。本研究以进一步挖掘玉米高产潜力和提高超高产玉米水分利用效率为目标,在不同产量水平、不同密植定额和不同节水措施条件下,对超高产春玉米根冠结构、功能特性进行系统研究,并结合超高产群体产量性能分析,揭示春玉米实现超高产的机理和产量挖潜的途径,探索建立超高产和水资源高效协调的技术途径。主要研究结论如下:1.超高产春玉米产量提高实质上是密度(EN)增加促使单位面积上总籽粒数(TGN)增加的结果。TGN的提高:一是通过增加密度提高单位面积收获穗数(EN),二是通过采用多花型品种和提高小花受孕率提高穗粒数(GN)实现。相关分析表明,平均净同化率(MNAR)通过影响穗粒数(GN)间接影响产量提高,说明通过优化群体结构,提高个体光合生产性能是产量潜力挖掘的重要途径。产量性能定量化分析表明,超高产春玉米安全群体的平均叶面积指数(MLAI)值为5左右;中大穗型品种应保持适宜密度,控制营养生长并加强花粒期管理,减少生长冗余、提高收获指数、增加粒重是其产量提高的主要途径;中小穗型品种耐密性较强,可以依靠密度增加产量,但密度不宜超过90000穗/hm2,生产上要优化群体结构,加强水肥管理,抗倒防衰,提高结实率和穗粒数,稳定千粒重。2.超高产春玉米根冠结构、功能特性具体表现为:群体冠层LAI增大,个体株型相对紧凑,上部叶片叶倾角和叶面积明显减小,下部叶片叶倾角略有减小且叶片面积较大,因而冠层在截获更多PAR的同时优化了冠层整体垂直空间上的光分布状态;使穗位及穗位以上叶片Pn和WUE显著提高,而穗位下部叶片不降低。超高产春玉米个体根系生物量略有减小,但群体生物量显著增加;根系生物量、总活力和活跃吸收面积横向分布相对集中,垂直方向上向土壤深层扩展比例增加。超高产春玉米群体“源”明显扩大,但“库”降低成为产量进一步提高的限制因子,采用耐密品种,减少败育粒,提高结实率,稳源扩库,协调源库比例,是超高产春玉米结构性挖潜的重要途径;而稳定植株下部叶片生产效率的基础上,提高植株穗位以上叶片的光合效率将成为产量挖潜中功能性挖潜的重要途径。3.超高产春玉米在密度增加过程中,生育后期叶片特别是穗位层以下叶片的衰老加快,光合性能和光化学效率降低,吐丝后LAD比例降低,不利于花后物质积累和产量的提高。但超高产春玉米可以通过自动调节补偿密度增加产生的不利影响,其群体冠层通过提高穗位层以上冠层的LAI弥补个体叶面积的降低;其个体通过自动调节中上部叶片的角度和弯曲度而相对紧凑使叶片处于较佳的受光位置,超高产玉米棒三叶上部叶叶倾角在高密度压力下小于20°,棒三叶叶倾角25°~35°之间,而棒三叶下部叶叶倾角为35°左右;随着密度的增加,根系的干物质量、总活力和活跃吸收面积横向分布趋于集中,垂直方向上向耕层以下的深层扩展比例增加。大穗型品种自动调节能力差,密度过高产量降低,中小穗型品种则在密度增加过程中表现较强的自动调节适应能力。根冠关系分析表明,根系分布越集中,在深层土壤中分布比例越大,株型越紧凑。因而,超高产条件下通过增加群体容量提高中上层叶片LAI,进而提高光能截获和利用率,同时提高深层根量和吸收面积比例,可以促进产量和水资源利用效率的提高。4.行间覆膜通过调节中上部叶片改善PAR在穗位层及下层的分布,同时提高叶片保护酶系统活性,提高中上部叶片在强光下的抗氧化能力并延缓下部叶片衰老;同时,行间覆膜明显提高玉米植株根系的生物量、总活力和总活跃吸收面积;横向上显著提高根系在宽行的分布量,扩大吸收的范围,纵向上提高根系生物量和总活跃吸收面积在耕层以下的分布比例。行间覆膜通过增加穗位上部冠层的LAI增加后期冠层的LAI,使超高产群体花后LAD比例和花后干物质积累比例显著增加,同时行间覆膜使子粒“库容”显著增大,群体“源库”协调,其增产作用始于营养生长和生殖生长并进时期,主要体现在生育后期。行间覆膜通过横向水分运移使玉米根系长期生长在土壤含水量相对较高的区域,通过提高降水和灌溉水利用效率显著提高水分利用效率。5.调亏灌溉使冠层和根系生长表现为明显的超补偿效应。各生育时期调亏复水后,叶面积皆明显增加,保护酶系统活性提高,各层叶片衰老进程延缓,花后叶片光合效率和水分利用效率显著提高,棒三叶上部叶片光合超补偿优势明显,下层叶片则在水分利用效率上体现超补偿优势;苞叶、叶鞘等非叶光合器官对产量的相对贡献在调亏灌溉下更加突出。根系生物量、活力和活跃吸收面积显著增加,且横向分布拓展,深层分布比例增加,复水后,表层根系和正在发育的深层根系同时表现出功能上的超补偿作用。行间覆膜条件下,不同生育时期调亏灌溉能显著降低不同生育阶段玉米群体的耗水量和耗水强度,显著提高超高产春玉米的WUE,运用行间覆膜和调亏灌溉综合农艺,可以实现产量提高20-30%,水资源利用效率提高20%以上的高产高效目标。更多还原

【Abstract】 The maize yield potential in irrigation districts of Inner Mongolia plain is highest in China, where the newsreel of super high yield spring maize was refurbished continually. At present, there were two main questions that limited yield promoting. First, the replaying of high yield newsreel in small area into large area was difficult, and the yield promoting was more and more diffcult; second, the illogicality between the shortage of water resource and low WUE in high yield potential regions limited yield promoting. The key of these tow questions was that the mechanism of super-high yield of maize and method of improving WUE were not clear. This research took the yield potential mining and the water use efficiency promoting as the final goal, and the structural and functional properties of canopy and root of super high yield spring maize was researched under different yield level, different density and different water saving agronomic measure. Based on it, and combined the yield properties analysis of super high yield colonies, the super-high yield mechanism and the way of yield potential mining were revealed, and the coordinate technical way of super-high yield and water resource saving was explored. The main result was expouned below.1. The essential of yield promoting of super high yield spring maize was the result of increasing of TGN unit area which was at the bottom of density increasing. There were two ways to increase TGN. One was to increase EN unit area; the other was to increase GN by adapting floribunda type maize and raising floret pregnancy rate. Correlation analysis showed that MNAR had indirect effect on yield by effecting GN. So promoting individual photosynthetic productivity by optimizing population structure was an important way to excavate yield potential. The MLAI value of safe super-high yield population was about 5 by quantitative analysis. The main way to promoting yield for middle and large ear cultivars should be to maintain suitable density, control vegetable growth and intensify the management in anthesis maturity period, so as to reduce growth redundance and promote harvest index and grain weight. Yield promotion of middle and small ear cultivars should depend on densitifacation, but the density should be less than 90000 ears per hectare, so optimizing population structure, enhancing water and fertilizer management, promoting seed-setting rate and stabilizing 1000 kernals weight were very vital in production.2. The structural and functional characteristics of root and canopy of super high yield spring maize mainly represented below. The population canopy LAI increased, plant profile was relative compact, leaf angle and leaf area of top leaves decreased, but leaf area of bottom leaves increased, so optimaizing the light distribution when intercepted more PAR.The Pn and LWUE of ear position leaves and top leaves of super high yield maize promoted remarkably while that of bottom leaves was not fall. The root biomass reduced a little but population biomass increased obviously. Root biomass, total vigor and active absorption area had relative centralized for transverse distribution and the distribution ratio in deep soil layer in vertical direction increased. The population source enlarged significantly but sink had become limited factor of increasing higher yield for super high yield maize. So construct a stable source, enlarging sink and coordinating the relationship of source and sink had become vital ways to excavate yield potential in population structure, furthermore, increasing the photosynthetic rate of top leaves and stabilizing that of bottom leaves was an important way for functional yiled mining.3. With the density increased of super high yield spring maize, the senescense of bottom leaves especially in anaphase accelerated and the photosynthetic properties and photochemical efficiency reduced, the LAD ratio after flowering reduced. All above block material accumulation and yield enhance after flowering stage. But the super high yield maize could regulate and compensated automatically for the adverse effect by increasing density. For example, the increasing of canopy LAI above ear could compensate the reduction of individual LAI. The individual plant could make the leaf at better light interception position by regulating the angle and bending of middle and top leaves automatically. Leaf angle above ear of super high yield maize was less than 20°, leaf angle of ear was between 25°and 35°, and leaf angle below ear was about 35°. Root dry matter, total vigor and active absorption area had centralized lateral distribution with the increase of density and the rate increased with the increase of soil depth. Root and canopy relationship analysis showed that the more centralized the larger of deep root rate. So the way of increasing yield and WUE was the increase of top leaf LAI.4. Covering film between furrows ameliorated the PAR distribution in canopy below ear through adjust the top leaves and middle leaves, meanwhile, promoted the protective enzyme system activity and the antioxidant capacity of leaves so as to delay leaf senescence. Biomass, vigor and active absorption area of root system were promoted under covering film between furrows, furthermore, the root distribution amount in wide row was increased then the absorption range was enlarged, and the distribution ratio of root biomass and root total active absorption area increased. Covering film between furrows increased canopy LAI in anaphase through promoted the canopy LAI above ear, therefore, the ratio of LAD and dry matter accumulation after flowering increased, meanwhile, the grain sink increased obviously, so the source-sink ratio was harmony. The yield increasing effect of covering film between furrows started in the abreast period of vegetable growth and reproductive growth, and mainly represented in anaphase. Covering film between furrows made a suitable water condition for root through water horizontal movement, and promoted water use efficiency through promoted the use efficiency of rainfall and soil water.5. Super compensate effect was incarnated obviously in canopy and root growth which was under regulated deficit irrigation treatments. Leaf area, protective enzyme system activity, photosynthetic rate and leaf water use efficiency was increased remarkably, and leaf senescence delayed obviously after rewatering in different deficit irrigation treatments. the top leaves had the super compensate effect in photosynthesis and the bottom leaves had the super compensate effect in water use efficiency, furthermore, the contribution of non-leaf organs such as bract and leaf sheath to yield was outstanding under regulated deficit irrigation. Regulated deficit irrigation promoted the dry matter, vigor and active absorption area of root remarkably, and the root function in top soil and deep soil all had the super compensate effect after rewatering. In the condition of covering film between furrows, regulated deficit irrigation could reduced water consumption and water consuming intensity remarkably, and promoted water use efficiency of super high yield spring maize. The comprehensive farming of covering film between furrows and regulated deficit irrigation could reached the goal of high yield and high water resource efficiency which promote maize yield by 15% to 30%, and promote water use efficiency above 20%.更多还原