【作者】 刘立军；

【导师】 杨建昌； 朱庆森； 张建华；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2005， 博士

【摘要】 氮肥利用率低是我国水稻生产中的突出问题。本研究从品种改良、实时实地氮肥管理、超高产水稻生长发育与养分吸收、土壤背景氮供应、品种源库特性、水分管理及强化栽培体系等方面研究了其对产量和氮肥利用率的影响,主要结果如下: 1.中籼品种改良对水稻产量和氮肥利用率的影响 试验以我国60年以来不同时期的16个代表性中籼品种为材料,研究了品种演进对水稻产量和氮肥利用率的影响。结果表明:品种改良逐步提高了水稻产量。产量的提高主要是由于总颖花量的增加。由早期高秆品种到矮秆品种,生物产量与收获指数的共同增加提高了产量;由矮秆品种到现代超级稻品种,产量的提高则主要是生物产量的增加。品种改良提高了粒叶比、根重和根冠比,减小了顶三叶叶片的着生角度,使顶部叶片更加挺立。 品种改良较大幅度地提高了现代品种的氮肥生理利用率、农学利用率和氮肥偏生产力,但没有明显提高氮肥吸收利用率。品种改良提高了抽穗前干物重和吸氮量以及抽穗后氮素向籽粒的运转。抽穗期吸氮量以及抽穗后氮素运转率与籽粒产量均呈显著正相关。穗分化期叶片中谷氨酰胺合成酶(GS)、硝酸还原酶(NR)和Fd-谷氨酸合成酶(GOGAT)以及灌浆初期籽粒中GS和NADH-GOGAT的活性对抽穗前干物质积累、氮素吸收以及抽穗后氮素运转起重要作用。水稻体内GS、NR和GOGAT等氮代谢主要酶类的活性明显受到氮肥的调节。提高穗分化期叶片和乳熟期籽粒中氮代谢酶的活性,可以增加抽穗前氮素和干物质积累、促进氮素向籽粒的运转并提高籽粒产量和氮素利用效率。刘立军:水稻氮肥利用效率及其调控途径 2.高产水稻需氮供氮的叶色诊断指标水稻叶片的叶绿素测定仪(S PAD)值与叶绿素含量(gm一2)和含氮率(gm勺均呈极显著的正相关,叶色卡(LCC)读数与SPAD值也呈明显的线性相关关系。SPAD值或LCC读数可以反映稻株的氮素营养状况并可依此作为水稻氮肥动态管理的重要诊断指标。研究明确了叶片SPAD值35和37可作为江苏主要釉稻和粳稻品种关键生育期施氮的临界值。对应的LCC读数为3 .0。在生产上示范应用验证了这些指标值的适用性和可靠性。 3.实时实地氮肥管理对水稻产量和氮肥利用率的影响依据土壤养分的有效供给量、水稻的目标产量、当季的氮肥利用率、主要生育期稻株需氮供氮的SPAD值和品种源库特征,建立了水稻实地实时氮肥管理模式(SSNM)。该模式在小面积上试验示范,施氮量较目前的习惯施肥法(CFP)减少了51 .9~56.3%,产量增加了0.2一9.3%,氮肥农学利用率提高了39.1一276.4%。2003一2004年在江苏省无锡市两村20户稻田中进行SSNM的示范,SSNM的施氮量较CFP降低了38.7~41.3%,产量提高了2.5~3.5%,氮肥农学利用率提高了88.3~117.7%。2004年在无锡、扬州和连云港市大面积示范推广,与CFP相比,SSNM的施氮量平均降低了42.0%,产量提高了3.2%,氮肥农学利用率提高了88.5%。 4.超高产水稻的生长发育规律和养分吸收规律与高产水稻(产量在8.9~9.5tha’,)相比,超高产水稻(产量>l1tha’,)的分桑成穗率较高(80%以上),叶面积指数抽穗前增加较快,抽穗期为7.5左右,乳熟后下降慢。全生育期总光合势以及抽穗至成熟期光合势应分别大于510和220扩dm一。抽穗前水稻积累的干物质约占最终干物质重量的60~65%,抽穗后茎鞘物质输出率在9一17%,收获指数>0.5。研究明确了超高产水稻主要生育期的氮、磷、钾吸肥量,其吸收高峰均在拔节至抽穗期,此阶段各养分的吸收量约占最终总吸收量的40~48%。超高产水稻每生产lt稻谷所需吸收的N、PZos和从0分别为1 9.5~22.1、14.2~巧.1和29.4~31.8 kg,粳稻略高于粕稻。 5.土壤背景氮供应对水稻产量和氮肥利用率的影响通过对前茬作物小麦设置施用氮肥与不施用氮肥处理研究其对土壤肥力及对后茬作物水稻产量和氮肥利用率的影响。结果表明,麦季氮肥的施用增加了稻季土壤全氮、钱态氮和硝态氮的含量,提高了土壤背景氮。与麦季不施氮(低土壤背景氮)相比,在高土壤背景氮下水稻产量对氮肥的反应明显降低,氮肥利用率的各个指标均有不同程度下降。表明在高的土壤背景氮下较高的氮肥施用量是水稻氮肥利用率低的重要原因之一。更多还原

【Abstract】 Low fertilizer-nitrogen use efficiency (FNUE) is a serious problem in rice production in China. This study investigated possible approaches to increasing FNUE from various aspects of genetic improvement (GI), real-time and site-specific nitrogen (N) management, growth and development and nutrient uptake in super high-yielding rice (SHY), indigenous N supply of soil (INS), source-sink characteristics of cultivars, water management and the system of rice intensification (SRI). The main results were as follows:1. Effect of GI in mid-season indica rice on yield and FNUE With 16 representative mid-season indica cultivars during the past 60 years in China as materials, effect of GI on grain yield and FNUE was studied. The results showed that GI increased grain yield gradually, and the increase in grain yield was due mainly to the increase of total spikelets per unit area. From early tall cultivars to dwarf cultivars, synchronous increase of biomass and harvest index increased grain yield; from dwarf cultivars to current super rice combination, the yield increase was attributed mainly to the biomass increase. GI increased spikelets per unit leaf area, root weight and the ratio of root to shoot, reduced the angle of top three leaves, leading to upper leaves more erect.GI significantly increased physiological efficiency (PE), agronomic efficiency (AE) and partial factor productivity (PFP) of N fertilizer of modern rice cultivars, but it did not increase recovery efficiency (RE). GI increased biomass and N uptake before heading stage and enhanced N remobilization after heading stage. N uptake at heading stage and N translocation efficiency were significantly correlated with the grain yield. Activities of glutamine synthetase (GS), nitrate reductase (NR) and Fd-glutamate synthase (GOGAT) in leaves at panicle initiation and GS and NADH-GOGAT in grains at early grain filling stage played important roles of biomass accumulationand N uptake before heading stage and N remobilization during grain filling. Activities of GS, NR and GOGAT in rice plant were significantly regulated by N application. Increase in activities of main enzymes involved in N metabolism at panicle initiation and early grain filling stage enhanced N uptake and biomass accumulation before heading stage, facilitated N remobilization from vegetative tissues to grains and increased the grain yield and N use efficiency.2. Leaf color diagnosis of high-yielding rice for N requirement and application SPAD (Soil and Plant Analysis Department) readings of leaves were significantly and positively correlated with chlorophyll content (g m-2) and N content (g m-2) in leaves. Significant correlation was also observed between leaf color chart (LCC) scores and SPAD values. SPAD values and LCC scores could reflect N nutrition status in rice plant and could be an important diagnosis index for dynamic N management in rice. SPAD values of 35 and 37 could be used as critical values for N application at key growth stages for most indica and japonica rice cultivars in Jiangsu, respectively, and the corresponding LCC score was 3.0. It was proved to be reliable and feasible in the demonstration and production of rice.3. Effects of real-time N management (RTNM) and site-specific N management (SSNM) on rice yield and FNUE SSNM model was established according to the available nutrient supply from soil, target grain yield, seasonal RE of N-fertilizer, SPAD values at main growth stages and source-sink characteristics of cultivars. Plot experiment showed that SSNM reduced amount of N application by 51.9-56.3%, increased grain yield by 0.2-9.3% and AE by 39.1~276.4%, respectively, relative to conventional fertilizer practice (CFP). SSNM was demonstrated in 20 farmers’ fields in two villages during 2003-2004 in Wuxi, Jiangsu province. Compared with CFP, SSNM reduced N rate by 38.7-41.3%, increased grain yield by 2.5-3.5% and AE by 88.3-117.7%, respectively. In 2004, the demonstration on a large scale in Wuxi, Yangzhou and Liangyungang showed that SSNM reduced N rate by 42.0%, increased grain yi更多还原