Nitrogen relations in winter wheat cultivars differing in grain protein percentage and stature

Accumulation of reduced nitrogen and its partitioning between vegetative tissue and grain are two important aspects of the nitrogen economy of wheat (Triticum aestivum L.). The objectives of this study were to 1) determine the range of nitrogen harvest index (NHI) among four hard red winter wheat cultivars differing in grain protein percent (GPP) and the influence of NHI on grain protein percent, and 2) to contrast the partitioning of nitrogen and dry matter to the component parts of the plant throughout growth and development. Plants were grown in a nutrient solution and nitrogen salts were withheld from the solution when the wheat reached anthesis. High nitrogen percentage of plant parts tended to correlate positively with grain protein percentage at first node and anthesis stages, but correlated negatively at latter stages. Dry weight was important in the accumulation of nitrogen; however, neither dry weight nor total plant nitrogen was correlated with GPP. Nitrogen harvest index was correlated strongly and positively with GPP and was independent of plant stature. The selection of parents with high NHI could be an important criterion in breeding programs to increase GPP of wheat.     

Partitioning of phosphorus in different height isolines of winter wheat

Wheat (Triticum aestivum L.) grain yields and composition are influenced greatly by P and its interactions with other nutrients. Because most P in grain, like N, is remobilized from vegetative parts, high harvest index of dwarf wheats may adversely influence partitioning of P to grain. Isogenic tall, single semidwarf, and double dwarf ‘Pawnee’ wheat lines were used to characterize P partitioning, P nutrition before and after anthesis, and relationship between P and N. Plants were grown in hydroponic cultures with three P levels; the first study determined P, N, and dry matter accumulation from anthesis to maturity, the second study determined the effect of withholding P after anthesis on P, N, and dry matter partitioning during grain development. Plants continued to absorb P when it was available after anthesis, but grain growth was influenced more by P nutrition before anthesis than after anthesis. Leaf blades, sheaths, and stems were major sources of P for grain growth when the nutrient was withheld and major sites of P accumulation when the nutrient was supplied after anthesis. Content of N in plants was favored by ample P levels. Dwarfing genes increased harvest index, but had little effect on P partitioning because of differences in dry matter accumulation.     

COURSE OF DRY MATTER AND NITROGEN ACCUMULATION OF SPRING WHEAT GENOTYPES KNOWN TO VARY IN PARAMETERS OF NITROGEN USE EFFICIENCY

Field experiments were conducted for two years to compare and identify bread spring wheat (Triticum aestivum L.) genotypes which make the most efficient use of nitrogen (N). Such information is required for breeding strategies to reverse the negative relationship between yield and protein content. Three Swiss spring wheat cultivars (‘Albis’, ‘Toronit’, ‘Pizol’) and an experimental line (‘L94491’) were grown without (N0; 0 kg N ha^?1) and with high fertilizer N [(NH₄NO₃); (N1; 250 kg N ha^?1) supply on a clay loam soil with low organic matter content. Biomass and nitrogen accumulation in biomass as well as the leaf growth and senescence patterns (SPAD) were investigated in an attempt to explain the physiology of growth and N translocation of these genotypes. The pre-anthesis accumulation of biomass and N in the biomass depended on genotype only at N1 in 2000. In this year, conditions were less favorable for the pre-anthesis accumulation of biomass and N, which was, on average, 10 and 20% lower, respectively, of the total than in 1999. The contribution of pre-anthesis assimilates to the grain yield (CPAY) was higher in 1999 for all genotypes (36.9%) compared to 2000 (13.5%) except ‘Toronit’. Between anthesis and maturity the climate influenced the genetic variability of some N use efficiency components: N translocation efficiency (NTE) and dry matter translocation efficiency (DMTE). NTE was higher in 1999 (68.1%) compared to 2000 (50.7%); 1999 was a year in which the post-anthesis period was drier and warmer than usual. ‘Toronit’ produced the highest biomass by maturity due mainly to greater and longer lasting green leaf area after anthesis. ‘Albis’ performed relatively well under low input conditions, with considerable amounts of N being re-translocated to the seeds at maturity (NHI), whereas ‘Pizol’ accumulated in grains N as high as for ‘L94491’. In a humid temperate climate breeding for greater N uptake and partitioning efficiency may be a promising way to minimize N losses and produce high phytomass and grain yields. Using high protein lines as selection material and combining them with high biomass genotypes may lead to high protein contents without decreasing yield.     

小麦氮素利用效率的基因型差异研究

研究了植株生长和产量性状差异很大的58个小麦基因型的氮素营养和利用效率。结果表明,开花期和成熟期植株各器官的含氮量和氮积累量,基因型之间差异显著;开花期剑叶含氮量与子粒含氮量呈显著正相关;每生产100公斤子粒需氦量,供试基因型变动于2.15～4.09公斤;氮收获指数的变幅为59.35％～82.89％,显示出小麦基因型在氮利用效率上的遗传差异。相关分析表明,每穗粒数、单蘖干物重、收获指数与氮效率比、氮利用效率呈显著正相关。     

中、高产型小麦干物质和氮素累积转运对水氮的响应

  【目的】  研究产量高低差异明显的小麦品种干物质和氮素积累转运对水氮响应的差异,为以产量为目标的小麦优化水氮运筹提供参考。  【方法】  于2016—2018年,以中产型品种‘泰科麦33’和高产型品种‘济麦22’为供试材料进行了两因素三水平完全方案田间试验。两因素为灌水量和氮肥用量,3个灌溉水平为300、450和600 m3/hm2,依次表示为W₁、W₂、W₃;3个施氮量为135、180和225 kg/hm2,依次表示为N₁、N₂、N₃。测定小麦关键生育期氮素和干物质积累量,在成熟期调查了产量和产量构成因素。  【结果】  两个品种小麦水氮互作效应对穗数、穗粒数、千粒重、籽粒产量和氮肥偏生产力影响显著,中产型品种的产量对水氮的响应顺序表现为W₂ > W₃ > W₁、N₂ > N₃ > N₁;高产型品种的产量对水氮的响应顺序表现为W₃ > W₂ > W₁、N₂ > N₃ > N₁。高产和中产品种产量对氮素的反应一致,高产品种比中产品种对水分的要求更高。品种特性及其水氮互作效应显著影响小麦开花期和成熟期干物质积累量。籽粒产量与花前干物质对籽粒的贡献率呈线性负相关,与开花后干物质对籽粒贡献率呈线性正相关,表明开花后干物质是籽粒干物质的主要来源。品种及其水氮互作效应均显著影响小麦开花期和成熟期氮素的积累量。籽粒产量与花前氮素积累量对籽粒的贡献率呈线性正相关,与开花后氮素积累对籽粒贡献率呈线性负相关,表明花前氮素积累是籽粒氮素的主要来源。在显著相关的性状中,生物量、开花后干物质输入籽粒量、开花后干物质对籽粒的贡献率之间呈显著正相关;花前氮素积累量、总氮素积累量、花前氮素转运量、开花后氮素输入籽粒量、花前氮素积累量对籽粒的贡献率以及氮素收获指数之间显著正相关。  【结论】  水、氮及其互作效应显著影响小麦穗数、穗粒数、千粒重、籽粒产量、氮素偏生产力、花前干物质积累量、成熟期干物质积累量、开花后干物质输入籽粒量、花前氮素积累量、成熟期氮素积累量、花前氮素转运量等性状。不适宜的灌水量和氮肥施用量会促进花前干物质向籽粒的过度运转,不利于形成高产。中、高产型小麦籽粒产量对氮素的响应均表现为为N₂ > N₃ > N₁,但对灌溉量的响应不同,中产型品种适宜的灌水量为450 m3/hm2,高产型品种适宜的灌水量以600 m3/hm2较为理想。     

地表覆盖和施氮对冬小麦干物质和氮素积累与转移的影响

在黄土高原南部旱区,通过田间试验研究了地表覆盖在不同氮水平下对冬小麦生长和氮素累积及转移的影响。结果表明,覆膜显著增加冬小麦各生育期干物质的积累,提高干物质转移量或花后干物质累积量;覆草显著增加生长后期干物质累积量,随种植年限的增加,覆草能显著增加冬小麦生物产量和子粒产量,其增产作用与覆膜无显著差异。覆膜亦能显著增加冬小麦各生育期氮素的积累,提高氮素转移量;覆草显著增加了生长后期氮的累积,随种植年限的增加,覆草对地上部吸氮量和子粒吸氮量的影响与覆膜无显著差异。施用氮肥显著增加了各生育期干物质和氮素的累积,促进花后干物质的累积和花前累积氮的再转移,显著提高了冬小麦地上部和子粒吸氮量及生物产量和子粒产量。     

Relationships among important traits in the nitrogen economy of winter wheat

Identification and utilization of important attributes in the nitrogen economy of wheat (Triticum aestivum L.) should provide a basis for increasing grain protein percentage (GPP). The objectives of this study were to determine the magnitude of genetic variability of some factors important in the nitrogen economy of wheat, their relationship to one another, and their influence on grain yield (GY) and GPP. Twenty‐five hard red winter wheat genotypes representing a wide range of GY, GPP, and plant stature were grown in field trials over a 2‐year period. Significant differences were found for harvest index (HI) and nitrogen harvest index (NHI). Total nitrogen at anthesis (TNA), total nitrogen at maturity (TNM), and biological yield (BY) did not differ significantly. GPP was positively correlated with TNM and BY and negatively correlated with TNA, HI, and GY. GPP was not correlated with NHI, however, stepwise regression of GPP and grain protein yield revealed NHI as a common component, with a positive coefficient. In addition, NHI was positively correlated with GY. Selection of parents with complementary traits for nitrogen‐use efficiency may allow for simultaneous increases in GY and GPP.     

不同筋型小麦干物质和氮素积累对追施氮量的响应

[目的]研究不同筋型小麦干物质和氮素积累对追施氮量的响应,揭示其干物质积累特征,为资源高效利用提供科学参考.[方法]田间试验于2016—2017年在中国农业科学院作物科学研究所北京试验基地进行,供试品种为强筋小麦'藁优2018'和'师栾02-1',中筋小麦'中麦8号'和'中麦175',弱筋小麦'扬麦22'和'扬麦15'...     

秋闲期秸秆覆盖与氮肥减施对旱地冬小麦干物质积累、结实特性和产量的影响

[目的]研究秋闲期秸秆覆盖对旱地小麦播前土壤墒情和小麦生产特性的影响以及减少氮肥用量的可行性,为四川旱地小麦高产高效管理提供理论依据.[方法]于2016―2018年在四川省仁寿县四川农业大学试验基地开展冬小麦–夏玉米轮作田间定位试验,供试作物为冬小麦.试验采用裂区设计,主区为夏玉米秸秆粉碎覆盖(SM)和不覆盖(NM);...     

Agronomic Assessment of Nitrogen Use Efficiency in Spring Wheat and Interrelations with Leaf Greenness Under Field Conditions

Four spring wheat genotypes (Triticum aestivum L.) were grown without (N0 = 0 kg N ha^?1) and under ample (N1 = 250 kg ha^?1) nitrogen (N) fertilizer in field experiments in two seasons. The aim was to assess genotypic variation in N use efficiency (NUE) components and N-related indices during grain filling thus to identify superior wheat genotypes. Leaf chlorophyll (SPAD) readings at crucial growth stages were employed to help differentiate genotypes. Interrelations between yield and N-related indices with SPAD, where also assessed to explain possible pathways of improving NUE early in the growing season. Results showed that genotypic effects on NUE were mostly evident in 2000, a year with drier preanthesis and wetter postanthesis than the normal periods. ‘Toronit’ almost always had the highest biomass yield (BY) and grain yield (GY). Except in 1999 under N0, ‘L94491? showed the highest % grain N concentration (GNC). Genotypes affected SPAD at almost all stages and N fertilization delayed leaf senescence for all genotypes and growth seasons. Correlations between SPAD at different growth stages and GY, N biomass yield at maturity (NBYM) and GNC were significant (P≤ 0.001), positive and strong/very strong (>r = 0.7). N translocation efficiency (NTE) was inversely related to PANU (~r = ? 0.77, P≤ 0.001), suggesting that N after anthesis is being preferentially transported to the ears to meet the N demand of the growing grains. It is concluded that there is still a large potential for increased NUE by improved N recirculation, use of fast and inexpensive crop N monitoring tools and high yielding, N uptake efficient genotypes.

Abbreviations: NUE, Nitrogen use efficiency; SPAD, Minolta SPAD-502 chlorophyll meter, NHI, nitrogen harvest index; HI, Harvest index; NTE, N translocation efficiency from vegetative plant parts to grain; DMTE, dry matter translocation efficiency; CPAY, contribution of pre-anthesis assimilates to yield; PANU, Post-anthesis N uptake, d.a.s., days after sowing, N0, zero (0) kg ha^?1 applied N fertilizer, N1, 250 kg ha^?1 applied N fertilizer.     

化肥减施下有机替代对小麦产量和养分吸收利用的影响

  【目的】  探讨化肥减施和氮肥有机替代对小麦产量、养分积累、运转和吸收利用的影响，为国家化肥零增长战略提供理论依据。  【方法】  于2017—2019年，定位研究了常规施肥 (CF)、等氮量有机替代 (有机替代30%N， CF+M)、化肥减施 (N、P₂O₅、K₂O分别减施25%、30%和16.7%，CFR)、减施替代 (有机替代30%N，CFR+M) 和单施有机肥 (M) 对小麦产量及其构成、生物量、不同生育期植株氮磷钾积累量、花前植株养分运转及花后养分积累、养分吸收利用的影响。  【结果】  与CF相比，CFR和CF+M处理小麦产量、成穗数和穗粒数均没有显著变化，千粒重有增加趋势；CFR提高了小麦拔节—开花阶段氮、磷、钾吸收量及其比例，CF+M与CF处理间各生育阶段尤其是拔节期后吸氮、钾量差异均不显著，而CFR处理开花—成熟期的氮磷吸收量显著降低，CF+M处理降低了花前茎叶氮运转量及花后氮磷积累量，CF+M、CFR和CF 3个处理间氮积累量差异不显著；CF+M提高了花前茎叶氮磷运转量对籽粒氮磷贡献率及花后氮积累量对籽粒氮的贡献率。籽粒氮素积累与各生育阶段氮素积累量、花前期茎叶氮素运转量及花后氮素积累量间呈显著或极显著正相关，籽粒磷素积累量仅与花后磷素积累量显著正相关，籽粒钾素积累量与返青—拔节阶段钾素积累量显著正相关，与花前颖壳+穗轴钾素运转量显著负相关。CFR和CF+M较CF提高了氮吸收、利用效率和氮肥偏生产力，CF+M较CF提高了钾素利用效率，降低了钾素吸收和钾素偏生产力。  【结论】  本试验的两年间，不同程度地减少氮磷钾化肥投入量，或不减少总氮量投入 (以30%有机氮替代化肥氮) 有利于花前期营养器官积累的养分向籽粒运转及籽粒对氮养分的吸收利用，都可以维持小麦产量。在减施氮肥量25%的前提下，用30%或者100%的鸡粪替代化肥则降低小麦各生育期干物质和氮磷钾养分的积累和运转，最终降低小麦的产量。因此，进行有机替代需要进一步研究适宜的氮肥减施比例。     

北部冬麦区主栽品种光合产物贮运特性研究

为解析北部冬麦区小麦品种光合产物积累与转运遗传特性,以近20年内主要推广的7个小麦品种为材料,通过两年两点田间试验,研究不同品种的生长发育生理动态、不同营养器官干物质积累分配、收获指数及籽粒产量。结果表明,收获指数和生物量对产量有显著影响。中麦816和中麦175具有较高产量潜力,分别为4 923.0 kg·hm^-2和4 913.0 kg·hm^-2,主要与其较高的生物学产量和收获指数有关。苗期群体光截获面积、灌浆期光能利用效率对干物质积累有重要影响。研究发现,灌浆期叶绿素含量低、旗叶面积小、光合速率高的品种,干物质积累效率较高,叶片和茎秆中可溶性糖贮积较多,如中麦175。在营养器官干物质分配方面,开花期中麦816和中麦175的各营养器官干物质贮积与其他品种差异较小,但成熟期叶片、茎秆干物质转运效率较高,贮积物残余较少,开花前中麦175和中麦1062贮藏的光合同化物对籽粒贡献最高。通过育种选择可提高光能利用效率和产量潜力,开花前干物质积累量和灌浆期干物质转运效率的选择,可减少成熟期营养器官光合产物残余,从而提高干物质向籽粒的转化效率。本研究进一步明确了新品种选育的目标与方向。     

氮肥减施对宽幅播种冬小麦产量形成和氮肥利用效率的影响

为明确氮肥减施对宽幅播种冬小麦产量和氮肥利用效率的影响,设置氮肥减施(减肥处理)、农户习惯施肥量(习惯施肥处理)、不施氮(无肥处理)3个处理,通过大田试验研究了不同处理冬小麦的群体动态、干物质积累特征、产量及其构成和氮肥利用效率的影响。结果表明,无肥处理的产量比习惯施肥处理低36.83%,而减肥处理的产量比习惯施肥处理高6.01%。无肥处理的最大茎蘖数显著低于习惯施肥处理,导致亩穗数和收获期生物量显著低于习惯施肥处理。减肥处理的最大茎蘖数也显著低于习惯施肥处理,但由于成穗率显著提高,亩穗数和收获期生物量与习惯施肥处理无显著差异。无肥处理的有穗单茎花后干物质积累量、花后干物质对籽粒的贡献率与习惯施肥处理无显著差异。而减肥处理的花后干物质积累量、花后干物质积累对籽粒的贡献率比习惯施肥处理分别显著提高39.70%和14.51个百分点。减肥处理的地上部氮吸收量与习惯施肥处理无显著差异,但氮收获指数提高2.97%,氮肥农学效率提高12.94%,氮肥偏生产力提高41.09%,氮肥利用率提高11.90个百分点。上述试验结果表明,宽幅播种配合氮肥减施可通过降低最大茎蘖数,提高成穗率,促进花后干物质积累及向籽粒分配,提高氮肥利用效率和产量。本研究为宽幅播种冬小麦实行氮肥减施提供了科学依据。     

Comparisons among cultivars of wheat,hulless and hulled oats: Dry matter,N and P accumulation and partitioning as affected by N supply

A better understanding of the impact of fertilizer nitrogen (N) on biomass and N accumulation, and their partitioning into different plant components is needed to optimize crop yield and quality. A field experiment with spring wheat (Triticum aestivum), hulless (Avena nuda), and hulled (Avena sativa) oats was conducted for 3 years in Ottawa, ON, Canada, to determine the crop responses to N addition (0, 75, and 150 kg N ha^–1). Biomass, N, and phosphorus (P) accumulation and partitioning into different plant components were examined during the growth season. Lodging score was determined for all crops when it occurred and again at harvest. During the growth season, both hulless and hulled oats and the wheat cultivar showed almost similar patterns of N and P accumulation with maximum contents at late grain filling or at harvest. Plant N concentration was up to 60 g kg^–1 during the seedling stage, decreased gradually with advancing growth stages, and was lowest at harvest. Nitrogen treatments significantly increased plant N and P contents. At heading stage, N treatments enhanced dry matter (24%–45%), N (35%–135%), and P (27%–45%) contents in plant components (i.e., culm, leaf, and head), but also enhanced crop lodging, especially in oats. Both hulled and hulless oats had higher total plant N (5%–35%), N : P ratio, and dry‐matter content in leaf (6%–43%) and head (0%–129%) along with higher P (up to 27%) in culm than the wheat cultivar. The wheat cultivar accumulated greater dry matter and higher N content in kernels than both hulled and hulless oats at harvest. Both hulled and hulless oat cultivars exhibited similar lodging susceptibility to N addition (75 or 150 kg N ha^–1), produced lower dry weight and lower kernel N, and hence lower grain yield than the wheat cultivar. The larger vegetative dry‐matter accumulation at heading coupled with higher P content in culms under high‐N‐supply conditions may be related to severe lodging in oat cultivars.     

水分胁迫下不同年代冬小麦品种干物质积累与转运特性

为了明确河南中部地区冬小麦品种改良过程中物质积累与转运特性及对水分亏缺响应的差异, 选取新中国成立以来6个不同年代主栽冬小麦品种, 采用测坑试验研究了冬小麦品种在不同水分胁迫(CK: 充分供水田间持水量的75%~85%; MD: 轻度干旱, 田间持水量的60%~70%; SD: 重度干旱, 田间持水量的45%~55%)下干物质生产与积累转运特性的演进特征及其与产量的关系。结果表明, 品种改良协调了干物质在各生育阶段的分配, 使花前和花后干物质积累与转运对籽粒的贡献更加平衡。在品种更替过程中, 株高和穗下节降低, 千粒重、籽粒产量和收获指数增加, 干物质积累总量无显著差异, 千粒重和收获指数的提高对产量增加起重要作用。在CK、MD和SD处理下, 20世纪90年代和2002年品种比20世纪50年代品种平均株高降低35.2%、36.2%和38.2%, 平均千粒重比增加31.7%、17.4%和56.3%, 平均籽粒产量增加40.4%、43.0%和52.4%; 20世纪90年代和2002年品种的收获指数比20世纪80年代及以前品种增加31.4%、22.3%和24.6%。CK处理早期品种干物质积累在抽穗至开花阶段超过现代品种。MD和SD处理的20世纪90年代及以后的品种花前干物质转运能力高, 茎秆干物质输出率增加, 花后贮藏物质积累降幅小, 干物质贮藏转运分配比例适宜, 对籽粒贡献率高, 是水分胁迫条件下现代品种高产的基础。     

栽培管理模式对冬小麦干物质积累、氮素吸收及产量的影响

为给小麦栽培管理提供指导,连续两个小麦生长季在河南省温县通过大田试验研究了农民习惯栽培(T1)、优化管理1(T2)、高产栽培管理(T3)、优化管理2(T4)4种栽培管理模式对冬小麦干物质积累、转运和氮素吸收、分配以及产量的影响。结果表明,与T1相比,T2通过基肥和拔节期追肥2次施肥,提高了干物质快速增长的时间和速率,增加了籽粒中干物质的积累和茎叶氮素向籽粒的转运,提高了穗粒数和粒重,从而达到产量和效率的提高;与T3相比,T4减少了氮磷钾用量,通过提高花后叶片中氮素的转运量和对籽粒的贡献率来增加粒重,在不降低产量的同时提高了养分效率。T3、T4模式与T1、T2模式相比,提高了干物质快速增长的时间和速率以及花后小麦茎叶贮存氮素向籽粒的转运量和对籽粒的贡献率。在本试验条件下,T2模式是目前生产情况下值得推广的优化栽培模式,T4模式是在产量进一步提高,达到高产条件下兼顾高产高效的最优栽培管理模式。     

Tillering,nutrient accumulation,and yield of winter wheat as influenced by nitrogen form 1

When grown with mixtures of nitrate‐nitrogen (NO₃‐N) and ammonium‐nitrogen (NH₄‐N) (mixed N) spring wheat (Triticum aestivum L.) plants develop higher order tillers and produce more grain than when grown with only NO₃. Because similar work is lacking for winter wheat, the objective of this study was to examine the effect of N form on tillering, nutrient acquisition, partitioning, and yield of winter wheat. Plants of three cultivars were grown to maturity hydroponically with nutrient solutions containing N as either all NO₃, all NH₄, or an equal mixture of both forms. At maturity, plants were harvested; separated into shoots, roots, and grain; and each part analyzed for dry matter and chemical composition. While the three cultivars varied in all parameters, mixed N plants always produced more tillers (by a range of 16 to 35%), accumulated more N (28 to 61%), phosphorus (P) (22 to 80%), and potassium (K) (11 to 89%) and produced more grain (33 to 60%) than those grown with either form alone. Although mixed N‐induced yield increases were mainly the result of an increase in grain bearing tillers, there was cultivar specific variation in individual yield components (i.e., tiller number, kernels per tiller, and kernel weight) which responded to N form. The presence of NH₄ (either alone or in the mixed N treatment), increased the concentration of reduced N in the shoots, roots, and grain of all cultivars. The effect of NH₄ in either treatment on the concentrations of P and K was variable and depended on the cultivar and plant part. In most cases, partitioning of dry matter, P, and K to the root decreased when NH₄ was present, while partitioning of N was relatively unaffected. Changes in partitioning between the shoot and grain were affected by N treatment, but varied according to cultivar. Based on these data, the changes in partitioning induced by NH₄ and the additional macronutrient accumulation with mixed N are at least partially responsible for mixed‐N‐induced increases in tillering and yield of winter wheat.     

Influence of Nitrogen on Growth,Yield, and Yield Components and Nitrogen Uptake and Use Efficiency in Dry Bean Genotypes

Dry bean is an important legume and nitrogen (N) deficiency is one of the most yield-limiting factors in most of the bean-growing regions. A greenhouse experiment was conducted with the objective to determine influence of N on growth, yield, and yield components and N uptake and use efficiency of 23 dry bean genotypes. Straw yield, grain yield, yield components, maximum root length, and root dry weight were significantly increased with the addition of N but varied with genotypes. The N × genotype interactions were also significant for most of these traits, indicating variation in responses of genotypes with the variation in N levels. There was significant difference in N uptake and use efficiency among genotypes. Most of growth and yield components were significantly and positively associated with grain yield. Based on grain yield efficiency index (GYEI), genotypes were classified into efficient, moderately efficient, or inefficient group in N-use efficiency. Nitrogen concentration was greater in grain compared to straw, indicating greater N requirement of dry bean genotypes.     

适宜微喷灌灌水频率及氮肥量提高冬小麦产量和水分利用效率

为明确微喷水肥一体化条件下灌溉次数和氮肥用量对冬小麦产量形成和水分利用的影响,该试验在灌水定额1 500 m3/hm2下设置微喷2次(拔节期750 m3/hm2+开花期750 m3/hm2)、3次(拔节期450 m3/hm2+开花期750 m3/hm2+灌浆期300 m3/hm2)、4次(拔节期450 m3/hm2+孕穗期300 m3/hm2+开花期450 m3/hm2+灌浆期300 m3/hm2)和氮肥追施45、90、135 kg/hm2处理,N肥随灌水等量分次施入,考察群体光合特性、物质生产和水分利用特征。结果表明:微喷3次和4次相比于微喷2次,产量提高了5.3%~18.9%,水分利用效率提高了5.3%~27.8%,但微喷3次与4次之间差异不显著。适当增加微喷次数提高了开花期和灌浆期群体绿色叶面积指数,延缓了叶片衰老,提高了生育后期干物质积累,增加了千粒质量,进而提高了籽粒产量;多次微喷(3次或4次)降低了总耗水量和开花前耗水比例,提高了开花后耗水比例;适当增施氮肥能进一步提高花后物质积累和花后耗水比例。综合来看,1 500 m3/hm2灌溉定额下微喷4次,追施氮肥90 kg/hm2产量和水分利用效率较高。     

施氮量对四川盆地小麦生长及灌浆的影响

【目的】施氮量对小麦光合产物的积累、转运和分配影响明显,氮肥运筹是调控小麦物质生产的重要手段。为进一步发挥四川盆地小麦的增产潜力,2011~2013年,在四川省江油市开展了施氮量对两个高产小麦品种物质生产及灌浆特性影响的研究。【方法】试验采用裂区设计,品种为主区,施氮量为副区,参数品种为内麦836和川麦104,施氮(N)水平分别为0、90、135、180、225 kg/hm2,在小麦生长期间和收获后分别测试了个体和群体生物量、产量、产量结构和灌浆参数。【结果】施氮量、品种以及年际间气候条件均对产量、产量结构以及干物质积累量、叶面积指数有明显影响,两因素或三因素互作效应因指标不同而异。同一施氮水平下,川麦104的籽粒产量高于内麦836,氮空白区内麦836平均产量6638.9 kg/hm2,川麦104为6717.7 kg/hm2。135 kg/hm2施氮水平下,两个品种的生物产量和籽粒产量分别超过18000和9000 kg/hm2,与180 kg/hm2和225 kg/hm2处理差异不显著。两个品种产量与施氮量之间的关系符合一元二次函数关系(P0.05),川麦104 y=-0.1056x2+44.023x+6724.6,内麦836 y=-0.0934x2+35.991x+6651.5,理论最高产量以及最高产量施氮量川麦104均高于内麦836。增加施氮量利于各生育期干物质积累量的增加,但在135~225 kg/hm2施氮范围变幅较小,且135 kg/hm2处理在花后物质积累量更多。随着施氮量的增加,花前贮存物质对产量的贡献率呈先降低后升高的趋势,135kg/hm2处理的产量形成更多的依靠花后物质生产。增施氮肥虽然可促进公顷穗数和穗粒数的增加,但平均灌浆速率下降,内麦836最大灌浆速率在施氮量达到N 180 kg/hm2,川麦104在施氮量达到N 225 kg/hm2时即有大幅下降,千粒重也随之有不同程度的降低。【结论】花后干物质积累量的差异是两个品种对氮肥响应出现差异的重要原因。在目前生产条件下,稻茬小麦高产施氮量在N 135~150 kg/hm2,即可确保小麦的产量,又可提高花前群体质量和花后物质生产量及转运效率。因此,在土壤肥力高、保水保肥力强的四川盆地,施氮量为135~150 kg/hm2可提升该地小麦的生产效益。