【作者】 王珏；

【导师】 陆卫平； 陆大雷；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2023， 博士

【摘要】 当前,作物产量差与效率差是一个研究热点。江苏玉米生产一直处于供不应求,如何改善这种情况以便更好满足人们的需求对保障江苏粮食安全发挥着至关重要的作用。因此明确江苏玉米产量差及其缩差增效技术途径具有重要意义。研究于2017-2019在江苏省徐州市、宿迁市和扬州市进行,以江苏省主要玉米品种江玉877为材料,经过调研构建了四个不同产量层次,并通过试验阐明四个层次间产量差与效率差形成机制,以及影响这些差异的主要因素,明确缩差增效主要技术途径。另外,于2019、2021和2022年在江苏省徐州市、宿迁市、镇江市,进行合理密度(75000株/hm~2、主推品种江玉877)下等量施氮下(225 kg/hm~2)的试验,探究缓释氮肥与普通氮肥配施调控江苏夏玉米增产增效的生理机制。主要研究结果如下:1江苏夏玉米产量差与效率差结果表明,江苏夏玉米农户产量与基础地力间产量差为1688.4～2781.0 kg/hm~2(平均2090.6 kg/hm~2),高产高效与农户产量间产量差为741.5～1763.8 kg/hm~2(平均 1178.4 kg/hm~2),氮肥偏生产力差为 19.9～32.3 kg/kg(平均 25.5 kg/kg),氮肥农学效率差为3.1～13.7kg/kg(9.3kg/kg),氮素利用率差为12.8%～19.7%(平均17.7%)。超高产水平与高产高效间产量差为758.3～2064.8 kg/hm~2(平均1212.8 kg/hm~2),氮肥偏生产力差为-12.3～-20.1 kg/kg(平均-15.3 kg/kg),氮肥农学效率差为-0.4～-6.5 kg/kg(平均-2.4 kg/kg),氮素利用率差为-2.0%～-9.6%(平均-6.4%)。超高产水平相比于高产高效产量更高,但是肥料利用率却反而降低,综合高产高效产量和效率最优,表明江苏省玉米缩差增效主要是缩减农户产量与高产高效间的产量差与效率差。2江苏夏玉米产量差与效率差形成机理和缩差增效技术途径基础地力与农户产量间产量差是由于农户产量增加了施氮量,提高了穗数、穗粒数、千粒重、生物量的积累速率和群体光能利用率,促进生物量的积累。研究发现可通过增加密度增加施氮量来缩减它们之间的产量差。农户水平和高产高效间的产量差和效率差是由于高产高效提高了穗数和生物量的积累速率,养分吸收周期延长,群体光能利用率提高,促进了生物量的积累,提高了肥料利用率显。研究发现可通过增加密度,优化施肥,精准定量施肥等栽培措施缩减它们的产量差和效率差。高产高效和超高产水平间产量差和效率差的原因是超高产水平增加了施氮量,提高了穗数、生物量的积累速率和群体光能利用率,促进了群体生物量的积累。研究发现可通过合理增密,推广施用缓释肥,化肥深施、追施来提高肥效,同时结合化控等栽培措施缩减它们的产量差和效率差。根据研究,我们明确了适宜密度下优化施肥是江苏玉米缩差增效的主要栽培技术途径。3适宜密度下优化施肥影响玉米产量的机制研究表明,75000株/hm~2密度和相同施氮量下(225kg/hm~2),缓释氮肥与普通氮肥配施对江苏玉米增产增效效果显著。且最佳配比比例为缓释氮肥与普通氮肥2:1配施(缓释氮肥150kg/hm~2:普通氮肥75kg/hm~2)。与单一施肥相比,配施可以增产2.2%～25.4%(平均9.3%),氮肥利用率增加2.5%～12.5%(平均9.6%)。配施显著增加了玉米花前营养器官转运率以及花后转运量对籽粒的贡献率,提高了氮肥偏生产力以及氮肥农学效率。通过对不同氮肥配施方式下叶片生理生化指标分析发现,配施处理下玉米叶片叶绿素相对含量、净光合速率、胞间二氧化碳浓度、蒸腾速率和气孔导度高于单一施肥处理。与单一施肥处理相比,配施下玉米叶片可溶性糖含量,可溶性蛋白含量,光合相关酶、氮代谢相关酶、抗氧化酶活性、叶片IAA含量均显著提高,ABA含量显著下降。转录组学和代谢组学分析表明,叶片的黄酮和类黄酮生物合成及植物激素信号传导途径积极响应了氮肥施用。结果表明配施通过影响叶片的光合能力,激素平衡、抗氧化系统,增强了光合作用,延缓了叶片衰老,增加了光合产物积累,从而提高了产量。更多还原

【Abstract】 At present,maize yield gap and efficiency gap are a research hotspot.Maize production has been in short supply in Jiangsu Province.How to improve the situation to meet people’s needs better plays a vital role in ensuring food security in Jiangsu.Therefore,it is of great significance to clarify yield gap and efficiency gap of maize in Jiangsu Province and the technical ways to reduce the difference and increase the efficiency.This experiment was conducted in Xuzhou,Suqian and Yangzhou of Jiangsu Province from 2017 to 2019,using Jiangyu877 variety from Jiangsu Province as the material.Through investigation and construction of four yield levels of summer maize in Jiangsu,the formation mechanism and main controlling factors of yield gap and efficiency gap were clarified,and the main technical ways of reducing difference and increasing efficiency wer clarified.Meanwhile,in order to explore the physiological mechanism of combined application of slow-release nitrogen fertilizer and common nitrogen fertilizer to regulate the yield and efficiency of summer maize in Jiangsu,an experiment of applying nitrogen at a reasonable density was carried out in Xuzhou,Suqian and Zhenjiang,Zhenjiang in 2019、2021 and 2022.The main results are as follows.1 Yield gap and efficiency gap of summer maize in Jiangsu ProvinceThe results showed that the yield gap between the yield of summer maize farmers and basic soil capacity was 1688.4～2781.0 kg/ha(mean 2090.6 kg/ha),and the yield gap between high yield and high efficiency was 741.5～1763.8 kg/ha(mean 1178.4 kg/ha).The difference of nitrogen partial productivity was 19.9～32.3 kg/kg(mean 25.5 kg/kg),the difference of nitrogen agronomic efficiency was 3.1～13.7 kg/kg(mean 9.3 kg/kg),and the difference of nitrogen use efficiency was 12.8%～19.7%(mean 17.7%).The yield gap between high yield and high yield and high efficiency was 758.3～2064.8 kg/ha(mean 1212.8 kg/ha),and the difference of nitrogen partial productivity was12.3～-20.1 kg/kg(mean-15.3 kg/kg).Nitrogen agronomic efficiency difference was 0.4～6.5 kg/kg(mean 2.4 kg/kg),nitrogen use efficiency difference was 2.0%～9.6%(mean 6.4%).Compared with the high yield and high efficiency,the yield of super high yield level was higher,but the fertilizer use efficiency was lower.The comprehensive analysis showed that high yield and high efficiency was the best,which indicated that the corn shrinkage difference and efficiency improvement of maize in Jiangsu Province was mainly to reduce the yield gap and efficiency gap between the farmers’ yield and high yield and high efficiency.2 Formation mechanism of yield gap and efficiency gap among maize populations and ways of reducing difference and increasing efficiencyCompared with the basic fertility,the panicle number,grain number per spike,1000-grain weight,biomass accumulation rate and population light energy utilization rate were increased by increasing the nitrogen application rate at the farmer’s level,which promoted the accumulation of biomass.The results showed that farmers could increase maize yield by increasing density and fertilizer.The yield gap and efficiency gap between farmer level and high yield and high efficiency were due to the fact that high yield and high efficiency increased panicle number and biomass accumulation rate,prolonged nutrient absorption cycle,improved population light energy utilization rate,promoted biomass accumulation,and significantly increased fertilizer utilization rate.This study found that the yield gap can be reduced and the efficiency gap can be increased by increasing the density,optimizing fertilization and precise quantitative fertilization.The reason for the yield gap and efficiency gap between high yield and high efficiency and super high yield level was that super high yield level increased nitrogen application amount,increased panicle number,biomass accumulation rate and population light energy utilization rate,and promoted the population biomass accumulation.Our research found that the fertilizer efficiency could be improved by reasonable densification,extended application of slow release fertilizer,deep application and topdressing of chemical fertilizer,and combined with cultivation measures such as chemical control to reduce yield gap and increase efficiency gap.3 Mechanism of optimal fertilization on maize yield under reasonable densityThe results showed that the combined application of slow-release nitrogen fertilizer and common nitrogen fertilizer had significant effect on the yield increase and efficiency of Jiangsu maize under the density of 75,000 plants/ha and the same nitrogen application rate(225 kg/ha).The optimal ratio of slow-release nitrogen fertilizer to common nitrogen fertilizer was 2:1(slow-release nitrogen fertilizer 150 kg/ha:common nitrogen fertilizer 75 kg/ha).Compared with single application of common N or slow release N,combined application could increase the yield by 2.2%to 25.4%(mean 9.3%)and increase the N use efficiency by 2.5%to 12.5%(mean 9.6%).Combined application significantly increased the pre-anthesis vegetative organ transport rate and the contribution rate of post-anthesis transport to grain,and improved nitrogen partial productivity and agronomic efficiency.Through the analysis of physiological and biochemical indexes of leaves under different nitrogen fertilizer combinations,we found that the relative chlorophyll content,net photosynthetic rate,intercellular carbon dioxide concentration,transpiration rate and stomatal conductance of maize leaves under different nitrogen fertilizer combinations were higher than those under single fertilizer treatment.Compared with single fertilization treatment,soluble sugar content,soluble protein content,photosynthetic enzymes,nitrogen metabolism-related enzymes,antioxidant enzyme activities and IAA content of corn leaves were significantly increased under combined fertilization,while ABA content was significantly decreased.Transcriptomic and metabolomic analysis showed that leaf biosynthesis of flavonoids and flavonoids and plant signal transduction pathways responded positively to nitrogen fertilizer.Physiological indicators showed that the photosynthetic index,enzyme activity and endogenous hormone content of maize were higher under combined application.These results indicated that combined application enhanced photosynthesis and respiration,delayed leaf senescence and increased the accumulation of photosynthates by affecting photosynthetic capacity,hormone balance,signal transduction and antioxidant capacity of leaves,thus increasing the yield.更多还原