玉米播期对大豆/玉米间作产量及种间竞争力的影响

在间作系统中,间作作物间合理的共生期可有效提高间作系统作物对时空资源的高效利用。而间作作物播期直接影响间作作物间共生期的长短,由此导致的时空生态位分离会直接影响到作物生产力和种间相互作用。为明确大豆/玉米间作系统中玉米播期对间作作物产量、系统生产力及间作作物间资源竞争力的影响,本研究设置3个玉米播期处理——M1(4月24日与大豆同时播种,与大豆共生期165 d)、M2(5月4日播种,与大豆共生期150 d)、M3(5月14日播种,与大豆共生期140 d),通过对单间作条件下作物产量、干物质累积的测定,研究了玉米不同播期下大豆/玉米间作系统作物产量、系统生产力、共生期内种间竞争力变化。结果表明:3个播期处理不影响间作产量优势,土地当量比(land equivalent ratio,LER)均大于1;但随播期延迟,LER变小,M1处理LER最大,达1.37。玉米播期变化对间作大豆产量无显著影响;随玉米播期延迟,间作玉米产量下降,间作系统生产力随之下降。玉米播期对间作大豆产量构成无显著影响;随玉米播期延迟,间作玉米的百粒重随之减小,M3的百粒重(26.1 g)仅为M1(36.6 g)的71%。玉米播期延迟抑制了大豆玉米共生后期玉米资源竞争力的恢复,在大豆和玉米共生前期,大豆的资源竞争力强于玉米,而共生后期(9月至收获),玉米的资源竞争力显著提升;M3处理大豆相对于玉米的资源竞争力(aggressivity,A_(sm))始终高于M1和M2,玉米相对拥挤指数随播期延迟而降低,表现为M1M2M3,而竞争比率为M3M2M1。因此,就本研究而言,甘肃河西灌区大豆/玉米间作系统中4月24日大豆和玉米同时播种是此系统间作作物的适宜播期,两作物同时播种可有效稳定间作作物产量及系统生产力,间作玉米播种延迟会导致间作系统生产力下降。     

4种生物质对大豆双共生系统、土壤微生物及产量的调控

通过田间试验研究施入生物质对根瘤菌、丛枝菌根真菌与大豆双共生系统、土壤微生物及大豆产量的影响。生物质设置秸秆、土豆皮、食用菌废弃料、大豆浸出液4个处理。分别在植株生长第4片复叶展开(V5)、结荚始期(R3)和鼓粒盛期(R6)取样测定。研究结果表明: 外施4种生物质对大豆双共生系统均有不同程度促进作用, 且生物质对大豆菌根形成的促进作用较对根瘤形成的促进更显著, 持续时间更长。在4种生物质中, 秸秆处理表现效果最佳, 不仅对大豆双共生系统、土壤细菌、真菌数量有增效作用, 同时对大豆产量有协同促进作用。在R6期大豆有效根瘤数量、丛枝菌根真菌侵染率、土壤细菌数量分别较对照增加238.46%、26.28%、131.99%, 产量较对照增加69.78%, 且秸秆容易获得, 施用方便, 是有效提高大豆产量的生物质。大豆浸出液处理对大豆双共生系统促进显著, 在R6期有效根瘤数量较对照增加89.74%, 同时丛枝菌根真菌侵染率较对照增加31.23%, 但由于此处理播种前采用浸种方式, 对大豆子叶造成较大损伤, 使保苗率严重降低从而导致产量相对较低。食用菌废弃料和土豆皮处理在3个生育时期对大豆双共生系统的作用不尽一致, 但R6期2个处理的丛枝菌根真菌侵染率和土壤中真菌数量都极显著高于对照。     

土壤中大豆根瘤菌优势类群以及与寄主共生关系的多样性

我国大豆种植区使用人工选育制成的根瘤菌剂接种效果不稳定。研究指出南方、北方和黄淮流域的6个省土壤中分布的主要Bradrhizobium.japonicum是DH444、USDA110、LL120、005和C224血清型的菌株,主要的Rhizobium.fredii是2048、USDA217、DE1611、2120和2077血清型的菌株。它们占每个取样地点分离物总数的60.3-81.6％。植物感染结瘤法测得大豆种植地点土著根瘤菌菌数在104/克土以上。盆栽试验表明大豆根瘤菌与大豆品种共生时有较强的亲和选择性和共生效应的多样性,其有效结瘤和固氮效率与根瘤菌个体菌株和大豆品种极相关。大多数土著大豆根瘤菌是低或中效固氮的菌株,因而认为选育抗土著根瘤菌而有利于人工接种菌株结瘤的大豆品种和强竞争性的高效菌株仍是提高我国大豆生产的有效途径。     

大豆高产的气象原因与生产对策

对大豆产量与相应的气象资料分析表明，在大豆的生产过程中，当≥７℃积温在２４００～２６５０℃·ｄ，５～９月降水量为３７０～５００ｍｍ时，对大豆生产最为有利，是大豆获得丰产的最佳水热条件。单一地确定大豆生长期的适宜降水或积温的最佳范围指标是不全面的，必须把两者结合起来。在降水偏多、热量充足的条件下大豆能获得高产，而降水偏少、积温适中的条件下也能取得丰收。并针对大豆生产过程中的气象条件，提出相应的生产对策。     

桑树大豆间作地上部和地下部的种间作用研究

在田间条件下研究了桑树-大豆间作体系中地上部分和地下部分之间的相互作用。结果表明:在桑树和大豆间作的共生期间,间作桑树地上部生物量、光合速率、含N量、根系干重、根长密度和叶片硝酸还原酶活性(NRA)比单作桑树分别增加了65.9%、11.8%、17.8%、24.8%、139.8%和116.2%,而大豆呈现相反趋势,桑树和大豆间作期间存在明显的竞争关系。但是,间作大豆土壤微生物生物量碳和土壤脱氢酶活性分别比单作大豆高10.6%和3.5%,桑树和大豆间作存在种间促进作用。因此,桑树和大豆间作体系中种间促进作用和种间竞争作用是同时存在的。     

见缝插豆—提高山芋田的利用率

山芋(亦称白薯、地瓜)沟内套种大豆能充分利用自然光温资源,提高土地利用率,增加收益。我县实行生产责任制后已大面积套种。春夏山芋都宜套种大豆。夏山芋一般在六月中、下旬麦收后扶垅栽插,八月上旬进入茎叶生长旺盛期开始封垅,山芋封垅前期约40天内70-95%的阳光漏射地面,芋沟内套种大豆后可减少光能损失。大豆一股30天左右即可开花,待山芋开始封垅时大豆已座荚,再共生20余天即可形成“毛豆米”(毛豆)。如     

大豆高产高效栽培技术要点

大豆是我国重要的油料作物,与人们日常生活联系紧密,且含有丰富的蛋白质、维生素、脂肪酸等营养物质,市场需求量较大,种植效益良好。在大豆种植过程中,受气候条件、病虫害、粗放式管理模式等因素影响,其产量、质量下降,生产效益难以提高。基于此,探究大豆高产高效栽培技术及其病虫害防治方法,以提升大豆产量,扩大大豆种植生产效益。     

镉、铅复合污染耕地主要作物安全生产阈值初探

为探明经济作物玉米、大豆及蔬菜作物紫菜苔、蒜苗、结球甘蓝、西蓝花在镉、铅复合污染耕地中的安全生产阈值,开展田间试验。结果表明,一定范围内,农产品中重金属累积量随土壤重金属含量增高而递增;重度污染条件下,玉米、大豆、蒜苗、结球甘蓝和西蓝花可实现安全生产,且安全生产风险玉米大豆西蓝花结球甘蓝蒜苗;紫菜苔于轻微污染条件下综合超标指数为0.67,可安全生产,但中度及重度条件下综合超标指数分别达到1.31、2.02,超标较严重,需规避种植。     

吉林省不同类型土壤中大豆根瘤菌的分布及人工接种的效果

土壤中的根瘤菌与豆类植物共生形成了共生固氮体系,为大豆生长发育提供了一部分氮素营养。根瘤的形成与固氮强度又决定于土壤中根瘤细菌的有无、数量和结瘤固氮活力。     

大豆保护性施氮的研究Ⅰ．氢醌在大豆保护性施氮中的效应

本文主要研究在施用尿素条件下，配加氢醌来延缓尿素的集中水解，以减少氨挥发并抑制其硝化作用，从而有效地缓解尿素对大豆共生固氮体系产生的严重抑制效应。结果表明，在一定的浓度范围内，氢醌对纯培养大豆根瘤菌生长。幼苗生长和初生结瘤无不利影响；对离体活性根瘤的呼吸活性和璃珀酸脱氢酶活性具有显著促进。在盆载或田间条件下，尿素配加ＨＱ施用，同无ＨＱ等量尿素比较，显著提高了大豆结瘤量和单株固氮总活性；提高了大豆木     

东北黑土区大豆生长、结瘤及产量对氮、磷的响应

氮肥和磷肥显著影响大豆的结瘤和产量。然而在土壤肥力较高、速效养分有效性差的东北地区,有关氮肥和磷肥施用量对大豆结瘤和产量影响的研究较少。本试验采用裂区田间试验,设置3个氮（N）水平（0、20 和 50 kg/hm2）和 3 个磷（P）水平（0、 20 和 40 kg/hm2）,研究氮、 磷及其交互作用对大豆生长发育、 结瘤特征及产量的影响。结果表明, 单施氮肥大豆生物量和产量随着施氮量的增加而增加,而根瘤数量、 干重、 大小和结瘤指数呈逐渐下降的趋势。单施磷肥促进大豆生物量、 产量、 根瘤数量、 干重、 大小和结瘤指数的增加,但其增幅低于施氮处理下的增幅。氮磷对大豆生长和产量促进作用高于单施氮和单施磷处理,但差异不显著;氮磷处理下的根瘤数量、 干重、 大小和结瘤指数低于单施磷处理;氮磷处理下N2（N 50 kg/hm2）处理下的大豆根瘤数量、 干重、 大小和结瘤指数高于N1处理（N 20 kg/hm2）下的,随着施磷量的增加大豆根瘤数量、 干重、 大小和结瘤指数增加,施磷能够抵消氮对大豆根瘤产生和形成的抑制。氮、 磷及其交互作用对大豆根瘤的影响都是直接的,并且不是通过促进大豆生长间接促进的。因此氮和磷均是限制东北地区大豆结瘤和产量的因素,但氮是主导因素。若要获得大豆高产,氮肥施用量需要控制在50 kg/hm2,磷肥在40 kg/hm2;但若想最大的发挥大豆的结瘤固氮功能,那么应该不施或者减少氮肥的施用量到20 kg/hm2,磷肥仍在40 kg/hm2。     

Selection of type A and type B strains for improving symbiotic effectiveness on non-Rj and Rj4 genotype soybean varieties

The selection of effective rhizobia for higher efficiency nitrogen fixation is one of the most important steps for inoculant production. Therefore, this experiment was conducted to select the most effective type A and type B strains for specific Rj-gene harboring soybean varieties and to test the symbiotic effectiveness of selected strains on different Rj-gene harboring soybean varieties. Screening experiments using the specific soybean varieties were done with a completely randomized design and three replications in this study. Evaluation of the effective Myanmar Bradyrhizobium strains for plant growth, nodulation and N₂ fixation were studied in pot experiments using sterilized vermiculite in the Phytotron (controlled-environmental condition). Then, a pot experiment was conducted using Futsukaichi soil in the screen house (natural environmental condition). The N₂ fixation ability of soybean was evaluated by acetylene reduction activity (ARA) and the relative ureide index method. In the first screening experiment, type A and type B strains with higher nitrogen fixation and proper nodulation on their respective soybean cultivars were selected for the next screening. In the second screening, Bradyrhizobium elkanii AHY3-1 (type A), Bradyrhizobium japonicum SAY3-7 (type A), B. elkanii BLY3-8 (type B) and B. japonicum SAY3-10 (type B) isolates, which showed higher nitrogen fixation and nodulation in Yezin-3 (Rj₄) and Yezin-6 (non-Rj), were selected for the next experiment. In the third screening experiment, SAY3-7 and BLY3-8, which had higher nitrogen fixing potential and proper nodulation, were selected as effective isolates. These two isolates were compatible with non-Rj and Rj₄ soybean varieties for nodulation and nitrogen fixation. Based on the results of the screening experiment, these two strains were tested for their symbiotic efficacy in Futsukaichi soil. This study shows that inoculation treatment of SAY3-7 and BLY3-8 significantly increased plant growth, nodulation, and N₂ fixation at the V6, R3.5 and R8 stages in Yezin-3 (Rj₄) and/or Yezin-6 (non-Rj), and the seed yield at R8 stage, in Yezin-3 (Rj₄) and Yezin-6 (non-Rj) soybean varieties compared with the control treatment. It can be concluded that SAY3-7 and BLY3-8 are suitable for inoculant production because of their higher nitrogen fixation ability, proper nodulation and better productivity of Myanmar soybean cultivars.     

不同施肥处理对水稻产量及其构成因素的影响

试验探索了前作(冬季)种植蔬菜的情况下,不同氮磷肥施用量与配施植物/土壤调理剂对水稻产量和产量性状的影响。研究结果表明,水稻产量与N、P肥施用量呈抛物线型关系,土壤植物调理剂在提高水稻N、P肥吸收利用率方面效果显著。本试验条件下,667m2施N5.9kg+P2O54.1kg+K2O5kg+土壤植物调理剂33kg,能获得高产。对于高需N、P品种,在合理施肥的同时配合使用土壤植物调理剂能充分发挥其产量优势。     

Symbiotic dinitrogen fixation - its dependence on plant nutrition and its ecophysiological impact

The cultivation of symbiotic legumes and the consequent small uptake of nitrate by the host plant depresses soil pH and impairs subsequent legume growth. The rate of soil pH decline depends on the soil H⁺ buffer power, climatic conditions, soil permeability, and on the kind of legume cropping. It is shown for some leguminous crop species from the temperate climate that in many cases the N₂ fixation performance of Rhizobium/Bradyrhizobium symbiosis is more dependent on the growth conditions of the host plant than on the nitrogenase potential of the bacteroid. This is true for the supply of the host plant with phosphate, potassium and water as well as for light intensity. Nitrogen deficiency of the host plant because of insufficient nitrogenase activity was observed at low soil pH where nodulation and the development of the nitrogenase activity were delayed. Nodulation and nitrogenase activity are suppressed by high levels of available nitrogen in the soil. There are indications that the nitrogenase activity is very flexible and adjusts to the demand of the host plant. The mechanism of this regulation is not yet understood.     

PHOSPHORUS USE EFFICIENCY FOR SYMBIOTIC NITROGEN FIXATION VARIES AMONG COMMON BEAN RECOMBINANT INBRED LINES UNDER P DEFICIENCY

This study compared the growth, nodulation, phosphorus use efficiency and nitrogen (N₂) fixation by six recombinant inbred lines (RILs) of Phaseolus vulgaris (RILs 147, 28, 83, 34, 7, and 104). These RILs were inoculated with Rhizobium tropici CIAT899 and grown in an aerated nitrogen-free nutrient solution at deficient versus sufficient phosphorous supplies (75 vs. 250 μmol P plant^?1 week^?1) in a glasshouse. Our results show that plant growth, nodulation, and symbiotic nitrogen fixation were significantly affected by P deficiency for all RILs, whereas this adverse effect was more pronounced in RILs 147, 83, 28 and 7 than in RILs 34 and 104. Under P deficiency, RILs 34 and 104 showed higher efficiency than other RILs in the use of P for their symbiotic N nutrition. It is concluded that P utilization efficiency may be a useful selection criterion for genotypic adaptation of N₂-fixing legumes to low P soils.     

Effects of co-inoculation of Bradyrhizobium japonicum SAY3-7 and Streptomyces griseoflavus P4 on plant growth,nodulation, nitrogen fixation,nutrient uptake,and yield of soybean in a field condition

ABSTRACT

Co-inoculation of nitrogen-fixing bacteria with plant growth-promoting bacteria has become more popular than single inoculation of rhizobia or plant-growth-promoting bacteria because of the synergy of these bacteria in increasing soybean yield and nitrogen fixation. This study was conducted to investigate the effects of Bradyrhizobium japonicum SAY3-7 and Streptomyces griseoflavus P4 co-inoculation on plant growth, nodulation, nitrogen fixation, nutrient uptake, and seed yield of the ‘Yezin-6’ soybean cultivar. Nitrogen fixation was measured using the acetylene reduction assay and ureide methods. Uptake of major nutrients [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] was also measured. This study showed that single inoculation of SAY3-7 significantly increased shoot biomass; nodulation; Relative Ureide Index (RUI %), percent nitrogen derived from N fixation (% Ndfa); N, P, K, Ca, and Mg uptakes; during the later growth stages (R3.5 and R5.5), compared with control. These observations indicate that SAY3-7 is an effective N-fixing bacterium for the plant growth, nodulation, and nitrogen fixation with an ability to compete with native bradyrhizobia. Co-inoculation of SAY3-7 and P4 significantly improved nodule number; nodule dry weight; shoot and root biomass; N fixation; N, P, K, Ca, and Mg uptake; at various growth stages and seed yield in ‘Yezin-6’ soybean cultivar compared with the control, but not the single inoculation treatments. Significant differences in plant growth, nodulation, N fixation, nutrient uptake, and yield between co-inoculation and control, not between single inoculation and control, suggest that there is a synergetic effect due to co-inoculation of SAY3-7 and P4. Therefore, we conclude that Myanmar Bradyrhizobium strain SAY3-7 and P4 will be useful as effective inoculants in biofertilizer production in the future.     

玉米/大豆和玉米/甘薯模式下玉米干物质积累与分配差异及氮肥的调控效应

【目的】西南山地玉米区是我国第三大玉米主产区,但单产比全国低近750 kg/hm2。由于该区特殊的气候条件,玉米以多熟间套种植为主,如何利用多熟种植中各作物的间套优势和茬口特性,寻求提高本区玉米产量的新途径,是农业科技工作者研究的热点。本文在四川的两个玉米主产区,通过四年的田间小区试验,对比研究了西南玉米主要的两种套作模式—玉米/大豆和玉米/甘薯模式下玉米干物质积累分配、转运差异及施氮量对其的调控效应,以探讨种植模式和氮肥管理的增产效应。【方法】2008年设置玉米/大豆和玉米/甘薯两个套种田间试验,分析比较两种模式玉米干物质积累、分配和转运的差异;2009 2010年在前一年的基础上分带轮作,即玉米分别种在大豆或甘薯茬上,分析套作和轮作效应对玉米干物质积累的影响;2011年,在前三年的基础上,采用小区套微区的方式,研究两种模式下不同施氮水平(N0、N90、N180、N270、N360)对玉米干物质积累和转运的调控。【结果】1)在玉米/大豆模式下,玉米干物质积累量从蜡熟期开始显著高于玉米/甘薯模式,茎鞘输出率也显著高于玉米/甘薯模式,最终产量增加2.4%3.2%,但差异未达显著水平;2)分带轮作后,从拔节期开始,玉米/大豆模式下玉米干物质积累量就显著高于玉米/甘薯模式,到成熟期两套种模式下玉米单株干物质积累两试验点平均相差达26.8 g,茎秆向籽粒的输出率和贡献率也显著高于玉米/甘薯模式,收获指数玉米/大豆模式平均较玉米/甘薯模式提高3.9%,最终玉米/大豆模式下玉米产量较玉米/甘薯模式增幅加大,两年两个试验点分别增加了7.4%和14.4%;3)氮肥对两种模式下玉米干物质积累分配和产量的调控效应显著,玉米/大豆模式下,玉米以施氮180kg/hm2处理,而玉米/甘薯模式下270 kg/hm2处理与同一模式下其他氮素水平相比,增加了光合产物的积累,提高了干物质增长速率,延长了灌浆持续天数,有利于茎鞘和叶片的干物质向籽粒转移,显著提高收获指数,进而提高玉米的增产潜能,玉米/大豆模式下低氮处理(0 180 kg/hm2)对玉米的增产效应比较明显,在高施氮水平(270360 kg/hm2)下两种模式间玉米产量差异不显著。【结论】西南丘陵旱地应选择玉米与大豆套作,采用分带轮作种植方式,既有利于提高玉米产量,又可避免大豆的连作障碍;且氮肥管理措施应因种植模式不同而有所差异,在中高等肥力条件下,与大豆套作玉米施氮180 kg/hm2,与甘薯套作施氮应提高至270 kg/hm2。     

The response of Stevia (Stevia rebaudiana Bertoni) to nitrogen supply under greenhouse condition

Stevia (Stevia rebaudiana Bertoni) is a perennial plant producing some natural sweeteners. Stevia is considered as a new crop in some countries. This study was conducted to find the stevia response to nitrogen fertilizer supply. Different levels of nitrogen (0, 30, 60, 90, 120, and 150 kg/ha from urea source) were used in a greenhouse condition and then the stevia growth and metabolites were assessed under different availability of nitrogen. Results showed that the optimum growth of stevia was obtained by 60 kg/ha nitrogen and more nitrogen supply did not enhance the stevia growth. It was observed that the total steviol glycosides (SVglys) content of Stevia was significantly increased by nitrogen fertilizer application just up to 30 kg/ha, while it decreased by more rates of nitrogen fertilizer. Our result clearly showed that SVglys yield reached to maximum value by application of 60 kg/ha of nitrogen fertilizer. Since the variation of SVglys content and shoot growth of the stevia were compromised by 60 kg/ha nitrogen, it can be concluded that 60 kg/ha of nitrogen fertilizer could be considered as an optimum rate of nitrogen for stevia and could also be recommended for greenhouse conditions.     

不同施氮量对甜瓜养分吸收、分配、利用及产量的影响

通过田间膜下滴灌栽培,研究不同氮素水平对甜瓜养分吸收、 分配及产量的影响。结果表明,增施氮肥显著提高了甜瓜的氮、 磷、 钾的积累量,特别是显著提高了甜瓜后期氮、 磷、 钾的积累量。在施P2O5 140 kg/hm2、 K2O 150 kg/hm2 的基础上施N 225 kg/hm2,甜瓜的养分吸收量和产量均为最高,各施氮处理甜瓜氮肥利用率在11%~29%之间,且随施氮量的增加而降低。甜瓜对钾的吸收量最高,氮次之,磷最少,表明甜瓜是喜钾作物。