叶片出口安放角对离心泵作透平噪声的影响

为研究叶片出口安放角对离心泵作透平内外场噪声的影响,运用声学边界元法(boundary element method,BEM)分析透平在叶轮和壳体壁面偶极子作用下产生的内场流动噪声,基于声学有限元的自动匹配层技术(finite element method/automatically matched layer,FEM/AML)计算考虑结构振动壳体声源作用的外场噪声,并验证了内场噪声计算方法和壳体结构有限元模型的准确性。结果表明,壳体偶极子作用的流动噪声能够体现多声源的共同作用,基于BEM法计算与试验频谱曲线吻合较好,叶频处误差仅为3.7%。效率随出口安放角的增加在全流量范围内均降低;以1/3倍频程A计权总声压级和总声功率级为评价指标,叶片出口安放角对透平噪声有一定影响;综合考虑水力性能和噪声,叶片出口安放角为30°透平综合性能较优。该文为后续噪声控制的研究提供了参考。     

高效低噪无过载离心泵多目标水力优化设计

为了整体提高离心泵水力设计水平,以叶频噪声声压级、扬程、效率和轴功率这4个指标作为判断标准,首次采用权矩阵方法借助数值模拟技术对离心泵叶轮进行了多目标优化设计。各指标的数值计算采用CFD/CA(computational fluid dynamics/computational acoustic,计算流体力学和计算声学)相结合的方法进行。基于L9(34)正交试验,深入研究了叶轮直径、叶片出口安放角、叶片出口宽度和进口安放角对离心泵扬程、效率、轴功率和流动噪声的影响规律,并根据权重分析获得了一组最佳几何参数组合。通过进行优化叶轮与原型叶轮的性能对比试验,发现该优化方案全部达标,设计流量下扬程提高2.5%,效率提高3.8%,轴功率下降3.3%,出口声压级降低1.2%,验证了权矩阵数值优化方法的可行性。粒子图像测速法内流场对比试验说明:优化方案无明显"射流-尾迹"流动结构的存在,其最大速度比原型泵小6.7%,低速区的面积比原型泵大,且由于减小了叶轮外径,叶轮和隔舌间的动静干涉作用也有所减弱;高效率低噪声离心泵叶轮设计的关键是选择合理的叶轮和隔舌间隙,以减弱叶轮出口的尾流脉动。该研究为实现高效、无过载、低噪声离心泵水力设计提供了参考。     

叶片进口安放角对泵作透平外特性影响的数值模拟与验证

为充分探究离心泵作透平专用叶轮叶片进口安放角的确定方法,该文建立了液力透平专用叶轮叶片进口安放角与设计流量的关系表达式;基于ANSYS Blade Gen与NX软件,分别设计了4个不同叶片进口安放角的透平专用叶轮;在试验验证基础上,通过全流场数值计算,分析了叶片进口安放角对透平外性能的影响。结果表明:叶片进口安放角从60°增大到72°、90°和105°时,透平高效点对应的流量分别为85、90、100和110 m3/h,4台透平数值计算最高效率点流量与理论计算设计流量基本吻合,表明采用该文推导的设计流量与进口安放角的关系式合理。外特性性能曲线显示随叶片进口安放角增大,透平高效点向大流量偏移,最高效率值有所下降,且下降的速率增大。综合考虑透平最高效率及高效区范围,对于比转速为193蜗壳式单级单吸离心泵反转作透平,叶片进口安放角宜设计在60°与90°之间。该研究可为液力透平专用叶轮设计提供参考。     

离心泵用作液力透平叶轮出口滑移系数的计算方法

为了通过理论的方法预测液力透平的性能,并针对国内外对液力透平滑移系数计算公式研究的空白,借助于离心泵滑移系数计算公式的研究方法和相关理论,结合流体力学中的相关原理研究液力透平叶轮流道中流体的流动形式,推导叶轮出口的滑移系数计算公式以及在考虑叶轮进出口滑移时液力透平的基本能量方程,最后选取模型对滑移系数计算公式进行验证,并与已有试验值进行比较分析。研究结果发现:随着比转数的增加,液力透平叶轮出口的滑移量逐渐减小,且对于大部分低比转数液力透平叶轮进口的滑移量小于叶轮出口的滑移量,而对于中、高比转数的液力透平叶轮进口的滑移量大于叶轮出口的滑移量。叶轮出口滑移量随着叶轮进口直径和出口安放角的增加而增大;随着叶片数的增加而减小;随着进口安放角的增加先增大后减小;而叶轮出口直径和叶轮进口宽度对液力透平叶轮出口滑移系数的影响较小,在研究液力透平叶轮出口滑移时可不考虑二者对液力透平叶轮出口滑移系数的影响。研究结果为采用理论的方法预测液力透平的性能提供参考。     

叶轮出口宽度对离心泵噪声辐射影响的分析与试验

为研究叶轮出口宽度对离心泵在水动力激励下泵壳振动辐射噪声的影响,该文以一台单级单吸离心泵为研究对象,保持泵体和叶轮其他几何参数不变,运用FEM\BEM（finite element method\boundary element method）声振耦合计算和试验测量方法进行了叶轮出口宽度分别为10、8和12 mm的噪声辐射分析。采用大涡模拟方法对离心泵内部瞬态流场进行计算,得到蜗壳壁面偶极子声源。在对泵壳体结构进行模态分析的基础上,利用LMS Virtual Lab的间接边界元IBEM声振耦合模块计算非定常流动引起的离心泵内部噪声,并进行了试验验证,在此基础上,对离心泵外场噪声及其声辐射进行计算,并研究了叶轮出口宽度对离心泵外场噪声辐射的影响。结果表明,离心泵叶片通过频率处的辐射声功率随着叶轮出口宽度的增大而增大;叶轮出口宽度存在一个合适的取值范围,使得各流量工况下外场噪声声压级较小;综合考虑离心泵能量性能与外场噪声,叶轮出口宽度为10 mm时,离心泵综合性能较优。研究结果可为低振动低噪声离心泵的水力优化设计提供参考。     

低比速多级潜水泵优化设计

按无过载设计要求,为大幅度提高效率,以QS10低比速潜水泵的优化为例,选择叶轮出口宽度、叶片进口冲角、叶轮叶片数、导叶进口安放角等10个参数为变化因素,按L27(310)正交试验方案设计了27组模型;研究了适合多级泵性能预测的方法;通过分析计算流体力学两级全流场数值模拟的结果,得到各几何参数对轴功率、效率指标影响的主次顺序:导叶叶片进口安放角β3对效率的影响最大,叶片出口安放角β2对轴功率的影响起主要作用;将正交分析所得到的最优方案制成样机进行性能测试,该优化模型泵额定点效率为58.61%(大于国家规定的效率值51%),最大轴功率值为3.83 kW(符合设计要求的4 kW),验证了正交设计结合数值模拟手段在泵优化设计方面的可行性。     

后掠式双叶片污水泵优化设计与试验

为了解决污水处理用排污泵叶轮易堵塞和磨损问题,该文设计了一种新型后掠式双叶片污水泵叶轮结构。采用正交试验的方法,按照L9(34)正交表,选取了叶片出口安放角β2、叶轮进口直径Dj、叶片出口宽度b2以及叶轮出口直径D2等因素,设计出了9组方案,通过正交试验分析了4个几何参数对泵性能的影响,得出叶轮出口直径D2是影响效率和扬程的最主要因素,并提出了优化设计方案。基于k-ε湍流模型及离散相零方程模型,对污水泵进行了固液两相流数值模拟,并将数值模拟结果与样机试验结果进行了分析对比。结果表明,双叶片、大包角、叶片前缘后掠的设计方法,可使颗粒杂质向外输送至叶片外周边,保证了固体颗粒或纤维的顺利通过,大幅降低了叶片的磨损,从而提高了泵的使用寿命,同时还具有较高的效率。通过样机试验得到优化设计方案在额定流量点的效率为80%,扬程为11 m,效率高于国家标准2.5%,该水力设计方法对污水泵水力设计具有一定的参考价值。     

泵作透平专用叶轮直径的确定及其对透平性能的影响

为了以理论方法建立前弯叶片泵作透平专用叶轮直径与设计流量的关系,揭示叶轮直径对透平性能的影响,该文以比转速为66的离心泵为原型,推导叶轮直径与设计流量的关系表达式。在不改变原型泵其他过流部件的前提下,基于ANSYS Bladegen软件设计3个进口安放角均为90°,直径分别为235、245和255 mm的前弯叶片透平专用叶轮。在试验验证基础上,分别完成3台透平全流场数值计算。结果表明:叶轮直径对透平外特性有显著影响,高效点随叶轮直径增加向大流量偏移。最高效率点均出现在计算临界流量稍偏右侧,与理论推导结论基本相符。叶轮直径从235 mm增大到245和255 mm时,透平最高效率分别提高了1.73%和3.32%。随叶轮直径增大,小流量区效率下降且降速快,大流量区效率提高且高效区宽。该研究丰富了液力透平设计方法,可为前弯叶片透平专用叶轮设计提供参考。     

农用无过载离心泵水力性能与内部流动计算

试验研究证明水力效率偏低(比普通泵约低2％～8％)是无过载离心泵效率较低的主要原因。为了提高水力性能,对无过载离心叶轮内部流动进行了数值模拟。采用IKhalil等人的计算方法,在子午面上用势流计算确定流面位置,回转面的计算则采用了完全粘性的湍流场计算方法。结果表明,无过载离心叶轮内部流动既没有出现分离,也没有明显的尾迹区存在。因此,水力效率偏低系由叶片包角过大、流道狭长、沿程水力摩擦损失过大所致。     

低比转数离心泵的多目标优化设计

为了提高IS50-32-160低比转数离心泵在设计工况下的扬程和效率,采用数值模拟、试验设计、近似模型和遗传算法相结合的优化方法,选取了泵叶轮的叶片出口宽度、叶片出口安放角和叶片包角3个参数作为设计变量,采用最优拉丁超立方试验设计方法进行20组方案设计,应用ANSYS CFX 14.5软件对各方案进行定常数值计算,得到设计工况下的效率和扬程,并将效率和扬程作为设计目标,根据Kriging近似模型建立了设计目标与设计变量之间的近似函数,采用遗传算法对近似函数进行求解,得到最优的叶轮参数组合。研究结果表明:原始方案的外特性数值模拟结果与试验结果吻合程度较好,设计工况下预测扬程偏差为3.3%;优化后的泵水力效率提高了4.18%,而且近似模型在预测性能的准确性高;通过对比原始方案和优化方案的内流场特性,优化方案内部流动得到改善,优化的叶轮的漩涡区域比原始方案的较小;优化使得效率在主频和次频下的脉动幅值分别下降了1.52和0.84,叶轮内的较大压力脉动强度区域减小,隔舌附近监测点在主频下的压力脉动系数幅值下降了0.02。非定常压力脉动强度降低,从而泵的运行稳定性提高。提出的优化设计方法对低比转数离心泵高效以及无过载特性的优化具有一定的参考意义。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.