不同氮源发酵的玉米秸基质对番茄育苗效果的影响

该试验分别以烘干鸡粪、尿素和硫酸铵为氮源发酵的玉米秸基质为原料,采用玉米秸基质∶蛭石=6∶4(体积比)为育苗基质,以草炭∶蛭石=2∶1(体积比)为对照,进行春季番茄育苗试验,研究了不同氮源及配比发酵的玉米秸基质对番茄育苗效果的影响。结果表明:采用25%烘干鸡粪氮 75%化学肥料氮发酵生产的玉米秸基质,在番茄日历苗龄35 d、40d时,其幼苗平均株高与对照基质相近,平均茎粗、平均根体积、平均最大根长均高于对照;日历苗龄40 d时,番茄幼苗地上部、地下部平均单株干重均略高于对照,采用该氮源配方发酵生产的玉米秸基质可以替代草炭用于番茄育苗。     

添加蛭石和鸡粪对玉米秸基质穴盘育苗的影响

玉米秸基质是一种新开发的替代草炭的基质,研究其在园艺作物栽培和育苗中的配套应用技术有重要意义。该文以番茄为试材,采用正交试验设计,研究了蛭石与发酵玉米秸基质的复配比例、烘干鸡粪添加量及基质相对含水率对玉米秸基质穴盘育苗的影响。结果表明：3因素对番茄幼苗地上部生长影响的主次顺序是鸡粪添加量＞基质相对含水率＞基质配比,对地下部生长影响的主次顺序是基质相对含水率＞基质配比＞鸡粪添加量;通过验证试验,综合考虑育苗效果及经济性得出最优组合处理为：基质相对含水率85%;玉米秸基质︰蛭石（V︰V）=1︰1;鸡粪添加量为每穴盘15 g。该试验结果为玉米秸基质应用及新基质开发提供了参考。     

水浸泡玉米秸基质对番茄育苗效果的影响

草炭是一种广泛应用的优良作物栽培基质,过度开采会对环境造成危害,研究性能稳定能够替代草炭基质的材料一直受到国内外的重视。该文把单位体积的玉米秸基质加入2倍体积的水中浸泡不同时间,风干后与一定比例的蛭石混配作为育苗基质,以草炭基质为对照,进行番茄育苗试验。在育苗期间,定期观测幼苗地上部、地下部的相关形态指标及干物质积累指标,研究水浸泡时间对玉米秸基质育苗效果的影响,结果表明：水浸泡的玉米秸基质能促进番茄幼苗的生长,增加地上部、地下部及全株鲜质量和干质量,并且这种效果随播种后天数的延长表现的更为明显;不同浸泡时间对番茄幼苗生长的影响有差异,延长浸泡时间对番茄幼苗的生长和干物质积累有明显促进作用,但浸泡时间过长,这种效果有减弱趋势,以浸泡10 d的处理育苗效果最优。浸泡10 d的玉米秸基质可以替代草炭基质用于番茄育苗,水浸泡是改良玉米秸基质理化性状的有效措施。     

菌糠复合基质在番茄育苗上的效果

以发酵菌糠为试验材料,研究了菌糠与草炭、蛭石、炉渣以不同比例(V/V)混合后基质的理化性质,并以复合基质进行了番茄育苗试验。结果表明,发酵菌糠的总孔隙度、持水孔隙度比草炭低11.8%、36.8%,通气孔隙度比草炭高41.9%,电导率比草炭高12.5倍。菌糠以30%～70%的比例与蛭石、草炭混合后,复合基质的理化性质与CK(草炭∶蛭石=7∶3)相近。在番茄育苗试验中,以T3(菌糠∶蛭石=7∶3)表现最好,T4(菌糠∶草炭∶蛭石=5∶2∶3)、T5(菌糠∶草炭∶蛭石=3∶4∶3)育苗效果均优于CK。     

玉米秸有机栽培基质矿质营养及理化性质分析

为了探索玉米秸秆作为有机栽培基质的可行性,采用塔式发酵设备,以玉米秸粉为发酵丰料,以烘干鸡粪和尿素为添加氮源,摔制发酵物料C/N为60,初始含水率为66%,经添加发酵菌、分段发酵、堆积后熟等过程制成玉米秸基质.试验测定了玉米秸基质和草炭的矿质营养含量及主要理化性质,分析比较了玉米秸有机栽培基质与草炭基质的差异,结果表明:除铁、锰元素含量略低于草炭外,玉米秸基质中其他主要矿质营养含量普遍高于草炭基质,腐殖酸含量较草炭低58.9%,持水空隙较草炭小24.1%,pH值呈偏碱性,电导率较草炭高2.7倍.在进行园艺植物育苗和栽培时,应对玉米秸基质含盐量高、偏碱性的特点加以调整.     

小麦秸秆混配基质对甜椒幼苗生长和光合参数的影响

将小麦秸秆、草炭和蛭石按不同比例混配成小麦秸秆混配基质,研究其理化性状及其在甜椒育苗中的应用效果.结果表明,随着混配基质中秸秆基质含量的增加,复合基质的容重、总孔隙度、持水孔隙度均呈上升趋势,而其通气孔隙度却呈下降趋势;添加小麦秸秆基质,提高了混配基质的pH值、电导率、阳离子交换量以及氮、钙、镁元素含量,降低了基质的磷元素含量;当小麦秸秆基质含量为36％时,T3处理(秸秆∶草炭∶蛭石为36∶54∶ 10)中甜椒幼苗的单株干重、壮苗指数、叶绿素总量均高于对照,分别比对照提高10.6％、8.4％、2.1％,其净光合速率则显著高于对照,比对照提高7.8％.因此,小麦秸秆∶草炭∶蛭石=36∶ 54∶10的混配基质适合于甜椒幼苗的生长发育,可作为甜椒育苗基质使用.     

猪粪沼渣用作育苗基质的效果研究

为探究猪粪厌氧发酵沼气工程沼渣用作育苗基质原材料的可行性,以玉米、黄瓜、水稻为供试作物,将沼渣与草炭、蛭石按一定体积比混配为不同配方的育苗基质,布置穴盘育苗试验研究不同配方基质对作物幼苗生长的影响,通过综合评价得出不同作物育苗基质的沼渣适宜施用比例.试验以传统育苗基质(草炭:蛭石=60:40)为对照(CK),用沼渣代替...     

氮钾肥配施对番茄幼苗生长及前期产量构成的影响

以尿素和硫酸钾为主要氮、钾肥料,以草炭和蛭石为育苗基质进行番茄育苗试验,研究分析了育苗基质中不同氮、钾肥料配施方案对番茄幼苗生长及其前期产量构成的影响,结果表明:番茄育苗过程中氮、钾肥料不同配比对番茄幼苗生长及前期产量存在显著影响,偏施氮肥或钾肥均可降低番茄出苗率、抑制番茄幼苗生长与干物质积累,氮、钾肥料合理配施可明显提高番茄幼苗素质,增加番茄前期开花数与座果数从而增加番茄前期产量,番茄基质育苗过程中氮、钾(N∶K2O)肥料最佳配比为1∶1.2。     

番茄工厂化育苗木糖渣基质与肥料配比研究

研究了以木糖渣为主料配合粉煤灰、煤渣与尿素、磷酸二氢钾、烘干鸡粪配成的不同基质对番茄幼苗生长的影响。结果表明：以６０％的木糖渣、３０％的煤灰、１０％的煤渣,每７２孔穴盘加尿素５ｇ,磷酸二氢钾５ｇ,鸡粪２０ｇ的配方做基质可代替蛭石、草炭用于蔬菜工厂化育苗降低蔬菜工厂化育苗成本。     

生物质炭醋糟复配物代替草炭对辣椒幼苗生长的影响

生物质炭的农业利用日益受到关注。针对草炭资源日益耗竭的问题,以药渣炭、木屑炭和猪粪炭为试验对象,配比一定量的醋糟,分析了不同配比生物质炭复合基质对辣椒幼苗生长的影响,探讨了生物质炭复合基质代替草炭基质的可能性。试验结果表明:生物质炭在与醋糟按4∶2、3∶3、2∶4等不同配比混合后,基质的pH大多数在6.0~7.5,基质的通气孔隙有所提高。综合整个幼苗生育期,含20%生物质炭的各复合基质处理的辣椒幼苗株高、茎粗、叶面积、地上部生物量均显著优于对照草炭基质;含20%、40%药渣炭的基质处理的幼苗根表面积、根体积表现较好,在前期与草炭基质无显著差异,后期显著高于草炭基质。药渣炭和木屑炭与醋糟混配基质的壮苗指数优于草炭处理,其中B1A2(药渣炭∶醋糟∶蛭石∶珍珠岩=4∶2∶3∶1)、B1A4(药渣炭∶醋糟∶蛭石∶珍珠岩=2∶4∶3∶1)、B2A4(木屑炭∶醋糟∶蛭石∶珍珠岩=2∶4∶3∶1)处理的壮苗指数均显著高于其他处理。综合评价各生长指标,B1A2和B1A4处理基质的表现最好,可代替草炭基质在辣椒育苗上应用。     

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.     

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.     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Increase in auxiliary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense

Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.     

In-situ enrichment and analysis of atrazine-degrading microbial communities using atrazine-containing porous beads

We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg⁻¹ buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg⁻¹ in conditioned and control soil, respectively. The results demonstrate that BioSep^® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation.