【作者】 汪瑞清；

【导师】 胡立勇；

【作者基本信息】 华中农业大学 ， 作物栽培学与耕作学， 2017， 博士

【摘要】 油菜芝麻复种模式是我国长江中游地区（湖北和江西）旱地的主要种植模式之一。目前,制约该模式快速发展的关键因子主要有二个,一是旱地油菜产量、效益、氮肥利用率都普遍偏低,不合理施肥的现象特别突出;二是油菜收获后农户习惯在上一年种植过芝麻的田块连作芝麻,而芝麻对氮肥需求量较小,增施氮肥往往导致连作芝麻病害加重,最终产量明显下降。因此,为了有效解决上述2个问题,提高油菜芝麻复种的总产量、总效益以及氮肥累计利用率,本文开展了该模式下不同氮肥施用量、施用时期与比例等对两个作物的产量、氮素吸收与转运、氮肥利用率的影响及其相关机制的研究,为该模式下氮肥高效利用及芝麻病害防治提供理论依据与技术指导。主要研究结果如下:（1）在每公顷施纯氮量270 kg基础上,减施45 kg纯氮,并采用油菜芝麻氮分配比例为202.5:22.5有利于提高总产量与总效益。不同氮肥用量显著影响油菜不同分枝部位的籽粒产量,且随着分枝部位的下降产量表现为先升后降。在华油杂62和华油杂9号中,氮肥用量从180 kg/hm²（T₁）增加到270 kg/hm²（T₂）可使油菜产量分别显著增加21.2%和44.2%,且T₂处理的氮肥累计吸收利用率（44.76%和52.80%）较T₁（对照）分别显著高出8.61和15.45个百分点。在每公顷施纯氮量270 kg的基础上减少45 kg,油菜芝麻前后茬氮肥分配比例为202.5:22.5时,总产量（3277.9 kg/hm²）和总效益（26455.1元/hm²）达到最高,较对照（P₀）分别显著增加了41.92%和53.88%。不同氮肥追施时间比较,以芝麻播后21d（21DAS）追肥45 kg/hm²处理的芝麻产量（1063.6 kg/hm²）、油菜芝麻总产量和总效益最高,分别为3272.4 kg/hm²和25934.4元/hm²。（2）油菜在低氮水平下的氮回收率显著高于高氮,基肥的氮素转运率显著高于追肥;油菜季施氮约有1.62%的残留氮被下茬芝麻吸收。油菜施氮研究表明,在N₁(0.15,g.N kg^-1.土)条件下,华双5号的¹⁵N回收率较N₂(0.30,g.N kg^-1.土)的显著增加了5.89个百分点,且最大差异在籽粒中。N₁处理的¹⁵N转运率（37.62%～37.70%）显著高于N₂处理的,而基肥的¹⁵N转运率要显著高于追肥的,主要差异分别在茎秆和叶片中。追肥处理的¹⁵N回收率（56.85%～61.60%）较基肥的分别显著增加了8.18和8.58个百分点,主要差异在籽粒和果皮中。在2个氮肥水平下,大约1.62%的油菜季施氮量被下茬芝麻吸收,油菜季基肥和追肥的芝麻¹⁵N回收率分别为1.91%和1.34%,且4个处理的产量较对照都有显著增加。（3）增施有机无机肥可显著提高油菜叶片PSⅡ最大光化学量子产量（Fv/Fm）和PSⅡ潜在活性（Fv/Fo）。氮肥用量对2个油菜品种不同位置叶片的PSⅡ实际光化学效率都有显著影响,其中对倒2叶至倒4叶的影响最明显。但增施氮肥降低越冬期油菜叶片的光合电子传递速率,尤其是倒2叶至倒5叶的影响更明显。（4）增施氮肥能够增加抗病芝麻品种病害发生率12.8个百分点,不同品种感病植株根际土壤中的细菌主要门类都有差异。在金黄麻和中芝35号中,患病株样品的青枯劳尔氏菌相对丰度较正常株的分别显著高出0.15和0.11个百分点。在抗病品种金黄麻中,N₁处理（105 kg/hm²）的Roseiflexus的相对丰度较N₀（0 kg/hm²）的显著下降了0.708个百分点。而在不抗病品种中芝35号中,N₀处理有5种属类的相对丰度较N₁的显著高出0.593～2.064个百分点,分别为uncultured-f-Acidobac-teriaceae＿Subgroup＿1,Candidatus＿Solibacter,Bryobacter,Rhizomicrobium,Sub-group＿2＿norank。尤其是金黄麻中患病株样品中的Phenylobacterium和假诺卡氏菌属（Pseudonocardia）的相对丰度较正常株样品显著增加了0.655和0.569个百分点;而中芝35号患病株样品中伯克氏菌属（Burkholderia）,Massilia,Phenylobacterium,新鞘脂菌属（Novosphingobium）的相对丰度较正常株的显著增加了1.007～1.867个百分点。芝麻根际土壤细菌的细胞运动、信号转导和翻译等功能受到植株病害的显著影响。总之,在油菜芝麻复种模式中,如果芝麻不施肥,则油菜氮肥用量应为270 kg/hm²,可以提高油菜芝麻复种模式总产量和氮肥利用率,还能够改善油菜倒2叶至倒4叶的叶绿素荧光参数。如果油菜芝麻氮肥用量减少45 kg/hm²,则前后茬氮肥分配比例应为202.5:22.5（kg/hm²）,且芝麻选择播后21d追肥较适宜。同时,连作种植地方芝麻品种（金黄麻）时应尽量少施或不施肥,有利于降低芝麻发病率和保持较高的产量。这是一项值得在油菜芝麻复种模式区域进行推广的高效简化节氮施肥技术体系。更多还原

【Abstract】 Rapeseed and sesame is one of the main planting patterns in the dry-land of middle reaches of the Yangtze River in China（Hubei and Jiangxi province）.At present,there are two key factors which restrict fast development of this pattern,the first factor is low yield and low nitrogen use efficiency of rapeseed in the dry-land,the phenomenon of unreasonable fertilization is particularly prominent;the second factor is that farmers used continuous cropping of sesame after harvesting rapeseed,and the demand for nitrogen fertilizer is a few for sesame and it often leads to aggravation of sesame disease with increasing of nitrogen fertilizer,and the final yield is obviously decreased.Therefore,in order to solve the above two problems and improve the total yield,total benefit and total nitrogen use efficiency of rapeseed and sesame multiple cropping,these were carried out that effect of application of different nitrogen fertilizer rates,the application period and proportion on the yield of two crops in this study,nitrogen absorption and translocation,nitrogen use efficiency and its related mechanisms.It can provide theoretical basis and technical guidance for high nitrogen use efficient and control sesame disease in this mode.The main results are as follows:（1）On the basis of applying 270 kg pure nitrogen per hectare,the reduction of 45 kg pure nitrogen and 202.5:22.5 of nitrogen distribution ratio for rapeseed and sesame would increase the total output and total benefit.The amount of nitrogen fertilizer significantly affected grain yield at different branches,and first rose and then fallen with the decrease of branch position.The experiment in Wuhan showed that the rapeseed yield increased by 21.2%and 44.2%,with increasing of nitrogen application rate from T₁（180kg/hm²）to T₂（270 kg/hm²）in Huayouza 62 and Huayouza 9,respectively.Meanwhile,total yield of rapeseed and sesame of T₂ treatment were the highest in two test points,and total nitrogen use efficiency of T₂ treatment（44.76%and 52.80%）were significantly increased by 8.61 and 15.45 percentage points than that of T₁ in Wuhan test point.Reducing the nitrogen fertilizer by 45 kg/hm² on the basis of 270 kg/hm²,the highest total yield（3277.9kg/hm²）and total benefit（26455.1 yuan/hm²）were observed in P₃（202.5:22.5,kg/hm²）treatment,which were increased by 41.92%and 56.66%compared with the control（P₀）,respectively.The sesame yield of 21days after sowing（1063.6 kg/hm²）was significantly increased by 69.63%compared with the control（without fertilization）,and the total yield and benefit of rapeseed and sesame of 21days after sowing were the highest among all treatments（3272.4 kg/hm² and 25934.4yuan/hm²）.（2）The nitrogen recovery efficiency of rapeseed under low nitrogen level was significantly higher than that of high nitrogen.The nitrogen transport efficiency of base fertilizer was significantly higher than that of top dressing.About 1.62%of the residual nitrogen of rapeseed was absorbed by the subsequent sesame.¹⁵N recovery efficiency(¹⁵NRE)of HS5 under N₁(0.15 g N.kg^–1 soil)significant increased by 5.89 percentage points compared to N₂(0.30 g N.kg^–1 soil),and the most obvious difference was observed in grain.The ¹⁵N transport efficiency(¹⁵NTE)of the N₁ treatment（37.62%～37.70%）was much higher than that of the N₂ treatment,with the difference mainly observed in stem.The ¹⁵NTE of basal treatment was significantly higher than that of topdressing,with the difference mainly found in leaves.The ¹⁵NRE under topdressing treatment（56.85%～61.60%）increased 8.18 and 8.58 percentage points relative to that under basal treatment,with the main difference observed in grain and pericarp.Additionally,about 1.62%of residual nitrogen from rapeseed season of the two N levels was absorbed by the subsequent sesame,and the average ¹⁵NRE of sesame from basal and topdressing were1.91%and 1.34%,respectively,with signifiant increased in yield compared to the control.（3）There was significant increased in PSII the maximum photochemical quantum yield（Fv/Fm）and PSII potential activity（Fv/Fo）of rapeseed leaf with increasing inorganic nitrogen fertilizer and organic nitrogen fertilizer treatment.Different nitrogen application rate showed significant effects on PSⅡactual photochemical efficiency of different position leaves in the two cultivars,especially for the top second leaf to fourth leaf.Nitrogen addition decreased leaf photosynthetic electron transfer rate during the overwintering stage of rapeseed,especially the top second leaf to fifth.（4）The application of nitrogen fertilizer can increase by 12.8 percentage point of the disease incidence of resistant sesame varieties.The diversity of main phylum in bacterial of rhizosphere soil was significantly affected by diseased.The relative abundance of Ralstonia solanacearum was 0.15 and 0.11 percentage points higher in Diseased sample from rhizosphere soil（D）than in Healthy sample from rhizosphere soil（H）samples for the two cultivars,respectively.N₁ had a significant decrease of 0.708 percentage points in the relative abundance of genus Roseiflexus as compared to N₀ in Jinhuangma with resistant varieties.Compared to N₁,the relative abundance of five genera,such as uncultured-f-Acidobacteriaceae＿Subgroup＿1,Candidatus＿Solibacter,Bryobacter,Rhizo-microbium,and Subgroup＿2＿norank,was significantly increased by 0.593～2.064percentage points in N₀ of Zhongzhi 35 with not resistant varieties.Furthermore,the D samples of Jinhuangma were 0.655 and 0.569 percentage points significant higher than H samples in the relative abundance of Phenylobacterium and Pseudonocardia.The D samples of Zhongzhi 35 were 1.007～1.867 percentage points significant higher than H samples in the relative abundance of Burkholderia,Massilia,Phenylobacterium and Novosphingobium,but it was just the opposite for other six genera.The function potential of bacterial community varied significantly between diseased and healthy samples.The cell motility,signal transduction and translation of bacteria from rhizosphere soil were significantly affected by the sesame disease.In short,without nitrogen fertilizer for sesame,nitrogen application rate for rapeseed should be 270 kg/hm² in rapeseed and sesame cropping pattern,and it can improve the rapeseed and sesame yield and nitrogen use efficiency.Meanwhile,it can also improve chlorophyll fluorescence parameters of rapeseed from pour second leaves to pour fourth leaves.If the total nitrogen application rate of rapeseed and sesame was reduced by 45kg/hm²,then the nitrogen distribution ratio of rapeseed and sesame should be 202.5:22.5（kg/hm²）and it was suitable for rapeseed and sesame under the condition of saving nitrogen fertilizer.Topdressing of 21days after sesame sowing was more appropriate in rapeseed and sesame cropping pattern.Meanwhile,the planting of local sesame variety（Jinhuangma）should be minimized or not fertilized,which can reduce the incidence of sesame and maintain higher yield.It was a simplified and saving nitrogen application technique system in rapeseed and sesame multiple cropping pattern which was worth promoting in the region of rapeseed and sesame multiple cropping.更多还原