【作者】 曹国军；

【导师】 赵兰坡；

【作者基本信息】 吉林农业大学 ， 土壤学， 2011， 博士

【摘要】 玉米在我国粮食生产中具有重要作用,对保障国家粮食安全意义重大。然而,在我国粮食需求和资源紧缺的双重压力下,增加粮食总产的唯一途径是提高单产。因此,要突破玉米目前的单产限制,发展可持续的玉米超高产技术,就要加强玉米超高产基础研究,不断丰富玉米超高产理论,揭示玉米超高产的形成机理,以指导玉米超高产实践,实现在有限的资源条件下生产出足够的粮食,保障国家粮食安全。为此,本研究采用了田间试验及室内检测相结合的方法,探讨了超高产春玉米的经济产量特性、生物产量特性、氮素和磷素营养特性,并进行了营养调控效果试验,力求从理论上揭示超高产春玉米的营养规律,并在实践中得以验证。研究结果如下：1、研究表明,超高产春玉米与其他产量相比,经济产量构成3要素均最高。春玉米要获得超高产其公顷穗数应>87200穗/hm2、穗粒数应>540粒／穗、千粒重应>280g。产量与产量构成因素的通径分析结果显示,超高产春玉米公顷穗数对籽粒产量的相对重要性最大,其次是穗粒数,千粒重影响最小。因此,同一品种,在相同密度条件下,春玉米获得超高产首先要注重减少空秆率及缺苗数,从而获得最大的公顷穗数；同时要创造良好的营养条件,减少籽粒败育和秃尖,提高穗粒数；在生育后期加强水肥管理,延缓叶片衰老,提高千粒重,实现超高产。2、超高产春玉米植株地上部生物产量以灌浆期—乳熟期最高,此阶段生物产量占总积累量的36.3%；超高产春玉米植株干物质最大积累速率及平均积累速率都高于其他产量,且最大积累速率出现的日期较晚,为出苗后86天,正值灌浆期。可见,超高产春玉米植株在生育后期表现出更明显的干物质积累优势,为经济产量的形成奠定了物质基础。3、超高产春玉米各器官干物质积累特性表现为：茎秆干物质积累的高峰是在乳熟期,而且峰值出现的时间比低产春玉米(CK处理)延迟20天；超高产春玉米各器官干物质转移量均最大,而其各器官干物质转移率和贡献率均最小。相反,低产春玉米(CK处理)各器官干物质转移量均最小,而各器官干物质转移率和贡献率均最大。超高产春玉米各器官总转移量占成熟期籽粒干物质重的比率为27.5%。而后期叶片光合产物直接运输到籽粒中的干物质重占粒重的比率为72.5%。可见,产量越高,籽粒对各器官干物质转移的依赖程度越低,而对生育后期叶片光合作用的依赖程度越高。4、超高产春玉米植株氮素积累的特性表现为在拔节期以后始终具有高度的氮素营养需求。体现出三个氮素营养调控的关键时期,即拔节期、抽雄吐丝期和灌浆期。最大吸收速率出现的时间为喇叭口期后的第三天。5、超高产春玉米叶片和茎秆在拔节期和抽雄吐丝期为氮素营养调控的重要时期。超高产春玉米氮素在各器官间分配特征表现为：各器官间氮素分配比例变幅缩小,各器官间分配比例更趋于均衡,这对保持生育后期营养器官具有一定的氮素分配比例,延缓营养器官过早衰老具有重要作用。超高产春玉米营养器官的氮素转移量虽然较大,但转移率和对籽粒的贡献率却较低。超高产春玉米籽粒中的氮素有46.7%来源于营养器官的转移,另有53.3%来源于生育后期根系的直接供给。6、超高产春玉米植株磷素吸收积累特点表现为在拔节期—喇叭口期、抽雄吐丝期—灌浆期磷的吸收速率和积累量明显高于其他产量水平春玉米；超高产春玉米磷最大吸收速率比其他产量水平高45.2%—-84.4%,磷最大吸收速率出现的时间为喇叭口期后的第五天。7、拔节期是超高产玉米叶片、叶鞘和茎秆磷素积累的瓶颈,也是磷素营养调控的关键时期。超高产春玉米磷素在叶片、茎秆中分配比例相对较高,而在籽粒中的分配比例相对较低。超高产春玉米营养器官的磷素转移总量最高,但转移率和对籽粒的贡献率却较低。超高产春玉米籽粒中的磷素有50.6%来源于营养器官的转移,另有49.4%的磷素来源于生育后期根系的直接供给。8、综合超高产生物产量特性及氮磷营养特性,本研究认为春玉米获得超高产的关键因素之一是要注重春玉米生育中后期的养分管理,延长营养器官的功能期,增强根系生育后期养分吸收能力,满足超高产春玉米后期对氮磷养分的需求；同时增强生育中后期叶片光合能力,促进生物产量的形成,为春玉米超高产奠定物质基础。本研究认为,在理论上,超高产春玉米氮素营养调控关键时期为拔节期和抽雄吐丝期。考虑到磷在土壤中的移动小,提出超高产春玉米磷素营养调控关键时期为拔节期,在拔节期追施磷肥在理论上是可行的。9、在本试验条件下,超高产春玉米养分调控技术为：氮肥施用量(N)360 kg/hm2,其中总施氮量的30%作基肥、10%作苗期追肥、25%作拔节期追肥、35%作抽雄吐丝期追肥；磷肥施用量(P205)为150 kg/hm2,其中施磷量的90%作基肥、10%作苗期追肥；钾肥施用量(K20)为225 kg/hm2,其中总施钾量的40%作基肥、30%作拔节期追肥、30%作喇叭口期追肥。上述养分调控技术可获得15000 kg/hm2以上的超高产水平。在本试验条件下,超高产春玉米氮磷钾施用比例为N:P205:K20=1:0.42:0.63；氮磷钾对产量的贡献率分别为27%、14%和17%,对产量贡献大小顺序为氮>钾>鳞。发现超高产春玉米追施钾肥具有较明显的增产效果。更多还原

【Abstract】 Maize plays a very major role in our country’s grain production and it has great significance to ensure national food security. However, under the double pressures of food needs and resources shortage, the only way to increase grain yield is to enhance the yield per unit. So the only way to break the limitation of maize yields per unit and develop the sustainable technology for maize super-high yield is to strengthen the basic research of maize super-high yield, enrich the theory and reveal the formation mechanism of maize super high yield, so that the theory can be used to guide maize super-high yield practice and give enough yield with limited resources to ensure national food security. This thesis combined field experiments and lab test, researched the characteristics of maize economic yield, biomass, N, P and tested the effects of nutritional regulation in order to find the nutrition rules of super-high yield maize and authenticate that theory in practice. The results are as follows:1、The three elements of economic yield in super-high maize were higher than those in other yield maize. Spring maize should have more than 87200 ears per hm2, more than 540 grain number per ear and more than 280g per thousand grain weight for super-high yield. The path analysis of yield and its elements showed that the most importance to grain yield is ears number per hectare, then is the grain number per ear and the weight per thousand grains. So for the same kind of maize and same density, spring maize should decrease the rate of empty pole and seedling in order to get the maximum ear number per hectare. At the same time, good nutrition, less abortion and bald tip should be made to enhance the number of ears. And water and fertilizer in the late growth stage should be strengthened to delay leaves aging, enhance weight per thousand grains and get super-high yield.2、The biomass of aboveground plants was the highest in filling-milky stage, whose biomass was 36.3% of total accumulation. The maximum and average accumulation rate of dry matter of super-high yield maize were higher than other yield, and the date of appearing maximum accumulation rate was 86 days after emergence, just during the filling stage. So the obvious advantage of dry matter accumulation rate could be found in the late growth stage of super-high yield, which established matter basis to the formation of economic yield.3、The accumulation of dry matters in different organs of super-high yield spring maize was maximum in the milky stage, the date of appearing peak was 20 days later than low yield spring maize (CK). The transfer amount of dry matters among organs was the highest in super-high yield spring maize, while the transfer rate and contribution rate was the least in super-high yield spring maize. The rate of transfer amount of super-high yield spring maize to dry matter weight in mature stage was 27.5%. And the rate of weight of dry matter in grain which transferred from leaves in photosynthetic products to the weight of grain accounted for 72.5%. So the higher yield we have, the lower of the dependence extent of grain on dry matter of various organs, and the stronger dependence extent on the leaves photosynthesis.4、Characteristics of nitrogen accumulation in super-high yield spring maize lies in a high and continuous need for nitrogen nutrition after jointing stage. Three key stages for N control were jointing,anthesis silking and filling stages. The maximum absorption rate appeared on the third day after bell stage.5、The jointing stage and anthesis silking stage were important to N control for leaves and stems of super-high yield spring maize. The characteristics of N distribution in various organs was that the change of N distribution rate among organs decreased and more balance, which was important to retain proper distribution rate of N among nutrition organs in the late growth stage and delay the organ caducity. Though the transfer amount of N was large, the contribution rate of transferring and grain was small.46.7% N of grain in super-high yield spring maize came from transform among nutrition organs and the other 55.3% came from roots in the late growth stage.6、The rate of P absorption and accumulation for super-high yield spring maize in jointing-bell stage and anthesis silking-filling stage was obviously higher than that in other stages. The max P absorption and accumulation rate of super-high yield spring maize was 45.2%-84.4% higher than that in other yield. The max rate of P absorption appeared on the third day after bell stage.7、The jointing stage is not only the bottleneck for P accumulation of super-high yield spring maize leaves、sheath and stem, but also the key stage for P nutrition control. The distribution rate of P in leaves and stem was high than other organs for super-high yield spring maize, and P in grain was relatively low. The P transfer amount among organs of super-high yield spring maize was the highest, but the transfer rate and the contribution rate to grains were relatively low.50.6% P in super-high yield spring maize came from other nutrition organs, but the other 49.4% came from roots supply directly in the late growth stage.8、According to the characteristics of biomass, N and P in super-high yield spring maize, this thesis showed that the key factor to get super-high yield for spring maize lied in as follows: the first was to pay attention to nutrition control of maize in the late growth stage. The second was to prolong the function stage of nutrition organ, at the same time, enhance the ability of absorb nutrition for roots in the late growth stage to satisfy the need to N and P for super-high yield spring maize in the late growth. The third was to enhance the ability of photosynthesis in the mid and late growth stage and promote the foundation of biomass in the late growth stage to make the basis for super-high yield of spring maize. This thesis also showed that the key stage of N control for super-high yield spring maize was the jointing stage and anthesis silking stage. According to the P transfer amount was low in the soil, the thesis proposed that the key stage of P control was the jointing stage, and it is feasible to fertilizer in this stage in the theory.9、This thesis showed that the nutrition control technology for super-high yield spring maize was as followed:The first was to apply N 360 kg/hm2, in which 30% of N was applied when plowing,10% when seeding,25% when jointing,35% when earring; the second was to apply P (P2O5) 150 kg/hm2, in which 90% when plowing, and 10% when seeding; the third was to apply K (K2O) 225 kg/hm2, in which 40% when plowing,30% when jointing,30% when bell stage. Above the nutrition control could get more than 16000 kg/hm2 with super-high yield. In this experiment, the ratio of N:P2O5:K2O was 1:0.42:0.63, the contribution rate of N, P, K to yield was 27%,14% and 17% respectively. The contribution rate to yield was N>K>P, and we found that yield could be obviously enhanced by increasing K.更多还原