【作者】 隋标；

【导师】 郭世伟；

【作者基本信息】 南京农业大学 ， 植物营养学， 2013， 博士

【摘要】 江苏省是中国主要的稻麦轮作产区之一,但目前在生产中面临着氮肥用量过高、产量徘徊不前以及氮肥利用率偏低的问题。因此,针对农户生产中存在的主要问题,控制该地区氮肥用量,合理调配其它养分的施用,同步提高作物产量和肥料利用率成为当前农业可持续发展的重要措施之一。本试验从2009年到2010年,在江苏省常熟市辛庄镇、白茆镇,2009年到2011年在如皋市袁桥镇农科所三地高、中、低三种肥力土壤上进行了连续的稻麦轮作的田间试验。试验中在水稻和小麦季均设计5个相同的处理：空白处理(Control, CK)不施用氮肥；农民习惯处理(Farmer fertilizer practice,FFP);三个优化施肥处理(Optimize treatment, OPT):分别为高效处理(High efficiency, HE),高产高效处理(High yield and high efficiency, HYHE)和超高产处理(Super high yield, SHY).本文通过研究江苏省稻-麦轮作体系在养分优化管理技术下水稻和小麦的生长发育,养分吸收,土壤养分供应规律以及水稻花后光合生理指标变化,明确了江苏省稻麦系统高产高效养分需求特征。结果表明：养分优化管理显著提高了稻麦轮作氮肥利用效率,改善了土壤氮素养分供应,使之更加符合作物的氮素需求规律,植株群体在生长前期更加合理,作物抽穗后光合速率等生理指标保持较高水平,进而提高作物产量,为实现江苏省水稻和小麦的高产高效生产提供相应的理论依据。主要研究结果如下：1.在江苏省水稻和小麦生产中,OPT处理在比FFP大幅降低氮肥用量的情况下,仍保持了较高的产量水平。HE、HYHE和SHY处理水稻平均施氮量分别比FFP处理降低了42.9%、17.6%和0.4%,产量分别比FFP处理增加了1.8%、4.0%和8.1%。HE、HYHE处理小麦平均施氮量平均比比FFP处理21.4%、1.3%,SHY处理与FFP处理氮肥用量相同,但三个处理小麦产量分别比FFP处理提高4.0%、8.2%和12.2%。从整个稻麦轮作体系来看,FFP处理平均总氮肥用量达到562.9kg/hm2,周年产量为14.2t/hm2；HE处理和HYHE处理分别为372.9kg/hm2和502.9kg/hm2,比FFP处理分别降低了33.8%和10.7%；SHY处理氮肥用量为561.7kg hm-2,三者产量分别达到14.6t/hm2、15.0t/hm2和15.6t hm-2,分别比FFP处理提高2.7%、5.7%和9.8%。2.OPT处理氮肥的回收效率(Nitrogen recovery efficiency, REN)、X农学效率(Nitrogen agronomy efficiency, AEN)和偏生产力(Nitrogen partial factor productivity, PFPN)均比FFP处理有所的提高。FFP处理水稻季氮肥平均回收利用率为29.8%,而HE处理、HYHE处理和SHY处理水稻季氮肥回收利用率分别为47.1%、36.2%和33.5%；FFP处理小麦季氮肥回收利用率平均为48.0%,而HE处理、HYHE处理和SHY处理小麦氮肥回收利用率平均分别61.8%、54.7%和57.9%。FFP处理水稻季氮肥农学效率只有7.6kg kg-1,HE、HYHE和SHY处理水稻氮肥农学效率分别为14.2kg kg-1、10.6kg kg-1和9.8kg kg-1。小麦农学效率均高于水稻,其中也是FFP处理小麦氮肥农学效率最低,平均为14.9kg kg-1;而HE、HYHE和SHY处理小麦季氮肥农学效率平均分别为20.7kg kg-1、17.2kg kg-1和17.7kg kg-1。FFP、HE、HYHE和SHY处理水稻季氮肥偏生产力平均分别为25.3kg kg-1、46.4kg kg-1、33.0kg kg-1和28.4kg kg-1;小麦氮肥偏生产力分别为24.3kg kg-1、32.7kg kg-1、26.7kg kg-1和27.1kg kg-1。FFP在所有处理中氮肥效率均最低,而HE处理氮肥效率最高。3.不同肥力土壤对氮肥的响应不同,其中低肥力土壤比高肥力土壤对氮肥响应更为敏感。随着土壤肥力的升高,水稻基础产量逐渐升高,如皋(低肥力)、白茆(中肥力)和辛庄(高肥力)空白处理水稻平均产量分别为5.1t hm-2、6.2thm-2和7.0t hm-2,而产量最高的超高产处理水稻平均产量分别为9.5thm-2、9.0thm-2和9.1thm-2。随着土壤肥力的升高,氮肥对水稻产量的提高效率降低。在小麦生产中,随着土壤肥力的升高小麦基础产量逐渐降低,如皋(低肥力)、白茆(中肥力)和辛庄(高肥力)空白处理小麦平均产量分别为2.7thm-2、2.0thm-2和1.8t hm-2,而在施肥处理中也是如皋试验点产量最高,平均高于6.6t hm-2,而白茆和辛庄平均产量在6t hm-2以下。同时无论水稻还是小麦,OPT处理在辛庄(高肥力)试验点产量比FFP处理产量提高幅度最低。说明相对于高肥力土壤优化处理在低肥力土壤上更容易提高作物产量。4.养分优化管理技术通过氮肥的后移减少了作物生育前期氮素的吸收比例,提高了生育后期氮素积累所占的比例。使作物前后期氮素吸收比例更加合理。氮素吸收规律的变化增加了水稻和小麦后期干物质的生产,并最终影响产量。移栽到穗分化期是水稻氮素积累最快的时期,其中FFP处理在这一时期氮素积累占全生育期的59.6%,OPT处理在穗分化期前氮素积累比为为46.0%-53.7%,穗分化之后氮素积累比例增加到46.3%-54%,FFP处理穗分化后氮素积累只占40.4%。水稻干物质的生产主要在穗分化后,约占全生育期的64.6-68.4%,穗分化前生物量生产只占31.6%-35.4%。OPT处理主要是增加了水稻后期特别是抽穗后干物质的生产,其占总生物量的比例为30.7%-33.1%,FFP处理抽穗后干物质生产只占总量的26.9%。FFP处理小麦在拔节前氮素积累占总量的42.5%,拔节后氮素积累的比例为57.5%；OPT处理拔节前小麦氮素积累占总量的33.7%-36.8%,拔节后氮素积累比例为63.2%-66.3%。小麦生物量在拔节前生产占总生物量的比例均低于20%,超过80%生物量是在拔节后生产的。其中FFP处理拔节后生物量积累比例为80.1%,而OPT处理拔节后生物量积累比例为83.9%-84.4%。5.在水稻分蘖期FFP铵态氮含量显著高于OPT处理,FFP处理铵态氮含量最高可以达到46mgkg-1, OPT处理在15～21mg kg-1.在穗分化后FFP处理铵态氮含量显著低于OPT处理。小麦季土壤硝态氮含量在越冬期最高,然后逐渐下降,OPT处理在孕穗期显著高于FFP。氮肥显著影响着叶片SPAD值的变化,与FFP处理相比,OPT处理前期叶片SPAD值较低,后期SPAD值高于FFP处理。但随着土壤肥力的升高,氮肥对叶片SPAD值的影响减弱。总体来说,优化的氮肥施用措施,改善了习惯施肥下作物生长前期土壤中速效态氮素过高,而中后期土壤中氮素缺乏的现象,使土壤中氮素含量变化更符合作物对氮素吸收的规律。6.OPT处理改善了水稻和小麦的群体生长指标。相对FFP处理,OPT处理降低了水稻和小麦最高分蘖数,但分蘖成穗率显著提高。随着基蘖肥中氮素用量的增加,水稻和小麦最高分蘖数随之提高,随着最高分蘖数的增加,分蘖成穗率逐渐降低。优化施肥中的HE处理和HYHE处理主要是通过提高成穗率实现最终的穗数,水稻分蘖平均成穗率由FFP处理的60%提高到70%左右。FFP处理前期过大的群体以及后期土壤氮素含量的降低会造成后期植株加快衰老,导致抽穗后水稻叶片光合速率只有17.6μmol m-2s-1,与空白处理处于同一水平,显著低于OPT处理。综上所述,采用养分优化管理技术,通过优化施肥可以改变土壤中养分含量的变化,使之更加符合植株对氮素的需求规律；降低了群体内个体间的竞争,使植株群体在生长前期更加健康合理；同时提高后期土壤氮素含量,使作物抽穗后光合速率等生理指标保持在较高的水平,延缓了植株衰老的速度,增加了花后生物量的生产,进而提高作物的产量。更多还原

【Abstract】 Jiangsu is one of the main regions with rice-wheat rotation system in china, however it has exist some problem such as excessive nitrogen(N) application, few yield increment and low N efficiency. Therefore, limiting the total nitrogens(N) application, reasonable allocating other nutrient, increasing the crop yield and fertilizer efficiency became the important measures for agricultural sustainable development. Field experiment with rice-wheat rotation system from2009to2011, in Rugao, Baimao and Xinzhuang which correspond with low, middle and high fertility soil respectively of Jiangsu province, was conducted to identify the nutrient characters of rice-wheat system with high yield and high fertilizer efficiency, the N absorption and utilization during winter wheat and rice growing seasons, and the dynamic nutrient supply in soil, and test the physiological change under the optimizing nutrient management, with the hope of providing theoretical basis for higher yield, higher quality and more effective production of paddy rice and wheat in Jiangsu province. The results obtained are as follows:With the optimizing nutrient managent, the yield of rice and wheat were keeped at high level which was higher than farmer practice, and the N application was marked lower than farmer practice. The total N rate of HE、HYHE and SHY were42.9%,17.6%and0.4%lower than FFP, respectively. In wheat season, The N rate of HE and HYHE was21.4%,1.3%lower than FFP, and SHY and FFP has the same N rate. From the whole rice-wheat system, total N rate of FFP was562kg hm-2, and the yield was14.2t hm-2. And the average N rate of HE and HYHE were372.9kg hm-2and502.9kg hm"2, which were33.8%and10.7%lower than FFP, respectively; the average N rate of SHY was561.7kg hm-2, it was similar with FFP. But the yield of HE、HYHE and SHY were14.6t hm-2、15.0t hm"2and15.6t hm-2, which were2.7%,5.7%and9.8%higher than FFP respectively.The recovery effeciency (REN)、agronomic efficiency (AEN) and partial factor productivity (PFPN) in optimizing nutrient management was higher than FFP. The REN of FFP、HE、HYHE and SHY for rice were29.8%、47.1%、36.2%and33.5%respectively. In wheat season, the REN of FFP、HE、HYHE and SHY were48.0%、61.8%、54.7%and 57.9%respectively. The AEN of FFP、HE、HYHE and SHY for rice were7.6kg kg-1、14.2kg kg-1、10.6kg kg-1and9.8kg kg-1respectively. In wheat season, the AEN of FFP、HE、 HYHE and SHY were14.9kg kg-1,20.7kg kg-1,17.2kg kg-1and17.7kg kg-1respectively. Whether in rice season or wheat season, the AEN in FFP was always the lowest. The PFPN of FFP、HE、HYHE and SHY for rice were25.3kg kg-1、46.4kg kg-1、33.0kg kg-1and28.4kg kg-1; and in wheat season were24.3kg kg-1、32.7kg kg-1,26.7kg kg-1and27.1kg kg-1. No matter in rice season or wheat season the PFPN of PFP was lowest, and the HE was the highest.There was different response of N application to crop in different fertility soil, and it was more sensitivity in low fertility soil than high fertility siol. The basic yield of rice was increased with the rise of fertility, as the rice yield of CK in Rugao、Baimao and Xinzhuang were5.1t hm-2,6.2t hm-2and7.0t hm-2, while the highest yield of this three sites were9.5t hm-2,9.0t hm-2and9.1t hm-2, respectively. Reversely, the N efficiency to heighten rice yield was reduced with the rise of soil fertility. At the wheat season, the basic yield had reduced with the rise of soil fertilizer, and the average yield of CK in Rugao、Baimao and Xinzhuang were2.7t hm-2,2.0t hm-2and1.8t hm-2. And the highest yield of wheat in these three sites was aslo in Rugao, its6.6t hm-2, it was6t hm-2in Baimao and Xinzhuang sites. At Xinzhuang site the yield increased by optimizing nutrient management was the lowest among three sites although where soil fertility was the highest. It suggested that it is easier to increase yield in low fertility soil relative to high fertility soil by the optimizing nutrient management.The optimizing nutrient management reduced the N absorption in the beginning period of rice and wheat, and increased the N absorption in following stage by re-allocation of N application. The change of N absorption in rice and wheat enhanced the biomass production at the last stage, and thus increased the yield. It was the most N accumulation stage of rice from transplanting to panicle initiation. The proportion of N accumulation rate to whole rice season at this stage was59.6%for FFP, and for the optimizing nutrient managements the proportion was46.0%～53.7%. The biomass of rice was mainly produced after panicle initiation, which accounted for64.6～68.4%. After heading, the proportion of rice biomass production for FFP was26.9%, while30.7～33.1%for the optimizing nutrient managements. At the wheat season, the proportion of N accumulation before shooting stage was42.5%for FFP, and was33.7-36.8%for the optimizing nutrient managements. But there more than80%of the biomass was produced after shooting stage, which was80.1% for FFP and83.9～84.4%for the optimizing nutrient managements.The highest ammonium content was present at tillering stage in rice, and the FFP treatment had higher ammonium content than the optimizing nutrient managements, for FFP it could reached46mg kg-1, for the optimizing nutrient managements it was just15～21mg kg-1. But after panicle initiation, ammonium content of FFP was lower than that of the optimizing nutrient managements. At the wheat season, there were two peaks for nitrate amount in soil, the first was before winter, and the second was at booting stage. In a word, the optimizing nutrient managements reduced the excessive N content at prophase of growing and improved the nutrient status at later growing stage compared to the FFP treatment, which synchronized the nutrient for crop demand with soil supply. The SPAD of leaf could indicate the N nutrition status for crops. It was changed along with the nitrogen content in soil. The leaf SPAD value for the optimizing nutrient managements was low at prophase of growing, and high at last growing stage to FFP.Compared to FFP, the optimizing nutrient managements improved the growing index for rice and wheat. With the N rate increase at basic and tillering stage, the most tillering of rice and wheat was increased, but the ratio of availability tiller was gradually declined. The ratio of available tiller of rice for HE and HYHE treatments were arrived at70%, while for the FFP was just60%. The large biomass at prophase of growing and low nitrogen supply at last growing stage for FFP could accelerate the senescence rapidly. After heading stage the photosynthetic of rice leaf for FFP was just17.6μmol m-2s-1, which was markedly lower than the optimizing nutrient managements.In summary, the optimizing nutrient managements synchronized the nutrient for crop demand with soil supply by changing the ratio and time of N application. It regulated the competition for nutrient and space at prophase of growing, and made the senescence slowly after heading, maintained the ideal crops growth condition, and realized the goal of reducing nitrigen fertilizer input and improving crop yield and nitrogen fertilizer use efficiency.更多还原