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1.
水稻高效利用氮素的生理机制及有效途径   总被引:52,自引:2,他引:50       下载免费PDF全文
 阐述了水稻高效吸收和利用氮素的生理机制,分析了水稻高效利用氮素的遗传潜力和改良途径以及农田资源管理技术对氮素效率的影响,并提出了需要研究的重要课题。  相似文献
2.
采用田间试验研究不同施氮量对两个玉米品种子粒产量、土壤硝态氮累积量及氮素利用率的影响。结果表明,玉米产量随施氮量增加显著提高,当施氮量高于200kg/hm2时玉米产量不再增加,高氮处理地上部分秸秆生物量出现下降趋势。0~100cm土层硝态氮累积量随氮素输入量的增加显著增加。不同玉米品种对氮素的吸收利用影响硝态氮在土壤中的累积,植株氮积累量存在差异。密植型玉米先玉335总吸氮量高于平展型玉米辽单28,土壤硝态氮的累积量也显著低于后者。不同氮肥水平的氮肥利用率为28.38%~35.33%,高氮处理氮肥利用率最低。本试验条件下,中氮处理水平基本能够满足作物生长的需求。综合产量、氮肥利用效率和土壤硝态氮累积情况,确定合理施氮量应控制在200kg/hm2左右。  相似文献
3.
为了研究不同水氮环境条件下小麦氮素含量和氮素利用效率(NUE)的遗传模型,随机选用8个亲本组配成28个双列杂交组合,在正常和水氮亏缺胁迫两种环境下进行随机区组试验,采用Hayman的分析方法研究了各性状的遗传模型。结果表明,在正常环境下籽粒和茎秆的氮素含量为加性-显性-上住性模型遗传,叶片氮素含量和氮素利用效率为加性-上住性模型遗传。在水氮亏缺胁迫环境条件下,籽粒和叶片氮素含量为加性-显性模型遗传。茎秆氮素含量和氮素利用效率为加性-显性-上位性模型遗传。可见,小麦氮素含量和氮素利用效率的遗传模型在不同的水氮环境中不完全一样。  相似文献
4.
水稻新品种盐粳188氮肥运筹技术研究   总被引:3,自引:2,他引:1  
采用小区对比试验方法,探讨了氮肥运筹对水稻新品种盐粳188生育及产量的影响。结果表明:基蘖肥与穗肥比例为2∶5∶3的B处理单位面积有效穗数、颖花数、抽穗至成熟期干物质积累量占产量的百分比及结实率、氮素利用率均高于其他处理,产量达720.45 kg/667 m2,分别比C(3∶4∶3)、D(3∶5∶2)、A(2∶4∶4)处理增产1.11%、2.93%、7.83%。  相似文献
5.
施氮量对稻季氨挥发特点与氮素利用的影响   总被引:2,自引:0,他引:2       下载免费PDF全文
 在砂土和黏土两种土壤类型上,研究了施氮量对田面水NH4+ N浓度、氨挥发损失量、水稻产量、氮肥利用效率和土壤剖面氮素含量的影响。施氮后田面水NH4+ N浓度和氨挥发量都随着施氮量的增加而增加,且在施氮后1~3 d达到峰值,黏土要低于砂土;氨挥发损失量为分蘖肥时期>倒4叶穗肥期>基肥时期>倒2叶穗肥期;黏土上稻季氨挥发总损失量为10.49~87.06 kg/hm2,占施氮量的10.92%~21.76%;砂土上稻季氨挥发总损失量为11.32~102.43 kg/hm2,占施氮量的11.32%~25.61%;施氮后氨挥发峰值和田面水铵态氮峰值同步出现,以分蘖肥时期最大,两者比值范围为23.76%~3365%;随着施氮量的增加,水稻产量增加,氮素积累量也增加,而氮肥利用效率降低;黏土上的水稻产量和氮素积累量要略高于砂土上的;土壤氮素含量在土壤深度40~50 cm处最低,相应各层土壤氮素含量随着施氮量的增加而提高,黏土要高于砂土。从氨挥发损失的角度来看,当施氮量超过250 kg/hm2时,氨挥发损失总量将跃增; 而从水稻获得高产的角度来看,施氮量应为300 kg/hm2左右,因此,试验条件下水稻高产且环境安全的适宜施氮量为250~300 kg/hm2。  相似文献
6.
施氮对圆叶决明生物固氮及氮肥利用效率的影响   总被引:2,自引:0,他引:2  
采用15N同位素示踪方法,对不同施氮水平下的圆叶决明生物固氨水平,氮肥的分配、氮素来源.以及氮肥的利用率、土壤残留、挥发损失进行研究.结果表明:圆叶决明生物固氮百分率随着施氮水平的增加呈先升高后下降的趋势,并在N2(30mg/kg)水平下达到最高,为29.50%,之后逐渐下降,且各处理间差异极显著.随着施氮量的增加圆叶决明对肥料氮的吸收增加,而对土壤氮的吸收降低.在较低(N2)施氮水平下,圆叶决明所需的氮主要来自土壤氮(56.17%)和生物固氮(29.50%);较高(N4)施氮条件下圆叶决明所需的氮主要由肥料氮(43.46%)和土壤氮(45.49%)提供.随着施氮水平的提高,圆叶决明氮肥利用率也逐渐降低,而氮素残留率逐渐升高.就氮肥损失率而言,N1(15 mg,kg)、N2(30 mg/kg)和N,(45 mg/kg)处理间的差异不显著,N4(60mg/kg)处理损失率最小.  相似文献
7.
氮肥运筹对超级稻盐丰47产量及氮素利用率的影响   总被引:2,自引:1,他引:1  
探讨了氮肥运筹对超级稻盐丰47产量及氮素利用率的影响,结果表明:基蘖肥与穗肥比例为2:5:3的B处理,获得了产量731.5kg/667m2,分别比C(3:4:3)、D(3:5:2)、A(2:4:4)处理增产了4.1%、4.8%、9.3%。同时表现为B处理的单位面积有效穗数、颖花数、抽穗至成熟期干物质积累量占产量的百分比及结实率、氮素利用率均高于C、D、A处理。  相似文献
8.
为合理调整不同氮素吸收利用效率油菜品种的氮肥用量,提高氮素利用效率,大田试验条件下,根据长江流域冬油菜主产区广泛种植的34个甘蓝型油菜品种的氮素吸收和利用效率的差异,以氮素吸收和利用效率的平均值为界线将供试品种分为4类,即A-高效吸收高效利用型、B-低效吸收高效利用型、C-高效吸收低效利用型和D-低效吸收低效利用型,研究4类油菜的生长性状、干物质及氮素积累和分配的特点。结果显示,A类品种在主序长、主序角果数、一次分枝数和一次分枝角果数等农艺性状上表现很强的生长优势,B、C两类居中,D类品种最低。氮素吸收效率高的品种,其干物质量、氮素积累量相对越多,不同类型油菜的地上部生物量及氮素积累量顺序为C、A>D、B;氮素利用效率高的品种,干物质量和氮素积累在籽粒中的分配相对较多,而在果壳中分配相对较少,籽粒产量以及籽粒氮素积累量顺序则为A>B、C>D。  相似文献
9.
Nitrogen (N) fertilizer represents a significant cost for the grower and may also have environmental impacts through nitrate leaching and N2O (a greenhouse gas) emissions associated with denitrification. The objectives of this study were to analyze the genetic variability in N-use efficiency (grain dry matter (DM) yield per unit N available from soil and fertilizer; NUE) in winter wheat and identify traits for improved NUE for application in breeding. Fourteen UK and French cultivars and two French advanced breeding lines were tested in a 2 year/four site network comprising different locations in France and in the UK. Detailed growth analysis was conducted at anthesis and harvest in experiments including DM and N partitioning. Senescence of either the flag leaf or the whole leaf canopy was assessed from a visual score every 3-4 days from anthesis to complete canopy senescence. The senescence score was fitted against thermal time using a five parameters monomolecular-logistic equation allowing the estimation of the timing of the onset and the rate of post-anthesis senescence. In each experiment, grain yield was reduced under low N (LN), with an average reduction of 2.2 t ha−1 (29%). Significant N × genotype level interaction was observed for NUE. Crop N uptake at harvest on average was reduced from 227 kg N ha−1 under high N (HN) to 109 kg N ha−1 under LN conditions while N-utilization efficiency (grain DM yield per unit crop N uptake at harvest; NUtE) increased from 34.0 to 52.1 kg DM kg−1 N. Overall genetic variability in NUE under LN related mainly to differences in NUtE rather than N-uptake efficiency (crop N uptake at harvest per unit N available from soil and fertilizer; NUpE). However, at one site there was also a positive correlation between NUpE and NUE at LN in both years. Moreover, across the 2 year/four site network, the N × genotype effect for NUpE partly explained the N × genotype effect for grain yield and NUE. Averaging across the 16 genotypes, the timing of onset of senescence explained 86% of the variation in NUtE amongst site-season-N treatment combinations. The linear regression of onset of senescence on NutE amongst genoytpes was not significant under HN, but at three of the four sites was significant under LN explaining 32-70% of the phenotypic variation amongst genotypes in NutE. Onset of senescence amongst genotypes was negatively correlated with the efficiency with which above-ground N at anthesis was remobilized to the grain under LN. It is concluded that delaying the onset of post-anthesis senescence may be an important trait for increasing grain yield of wheat grown under low N supply.  相似文献
10.
Nitrogen (N) fertilizer represents a significant cost for the grower and may also have environmental impacts through nitrate leaching and N2O (a greenhouse gas) emissions associated with denitrification. The objectives of this study were to analyze the genetic variability in N-use efficiency (grain dry matter (DM) yield per unit N available from soil and fertilizer; NUE) in winter wheat and identify traits for improved NUE for application in breeding. Fourteen UK and French cultivars and two French advanced breeding lines were tested in a 2 year/four site network comprising different locations in France and in the UK. Detailed growth analysis was conducted at anthesis and harvest in experiments including DM and N partitioning. Senescence of either the flag leaf or the whole leaf canopy was assessed from a visual score every 3-4 days from anthesis to complete canopy senescence. The senescence score was fitted against thermal time using a five parameters monomolecular-logistic equation allowing the estimation of the timing of the onset and the rate of post-anthesis senescence. In each experiment, grain yield was reduced under low N (LN), with an average reduction of 2.2 t ha−1 (29%). Significant N × genotype level interaction was observed for NUE. Crop N uptake at harvest on average was reduced from 227 kg N ha−1 under high N (HN) to 109 kg N ha−1 under LN conditions while N-utilization efficiency (grain DM yield per unit crop N uptake at harvest; NUtE) increased from 34.0 to 52.1 kg DM kg−1 N. Overall genetic variability in NUE under LN related mainly to differences in NUtE rather than N-uptake efficiency (crop N uptake at harvest per unit N available from soil and fertilizer; NUpE). However, at one site there was also a positive correlation between NUpE and NUE at LN in both years. Moreover, across the 2 year/four site network, the N × genotype effect for NUpE partly explained the N × genotype effect for grain yield and NUE. Averaging across the 16 genotypes, the timing of onset of senescence explained 86% of the variation in NUtE amongst site-season-N treatment combinations. The linear regression of onset of senescence on NutE amongst genoytpes was not significant under HN, but at three of the four sites was significant under LN explaining 32-70% of the phenotypic variation amongst genotypes in NutE. Onset of senescence amongst genotypes was negatively correlated with the efficiency with which above-ground N at anthesis was remobilized to the grain under LN. It is concluded that delaying the onset of post-anthesis senescence may be an important trait for increasing grain yield of wheat grown under low N supply.  相似文献
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