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土壤养分有效性的核心问题是土壤中养分离子向根的迁移,而离子向根迁移则是由于植物根吸收水分和养分产生的梯度所引起。 相似文献
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南亚热带不同植被根际微生物数量与根际土壤养分状况 总被引:28,自引:0,他引:28
研究了包括尾叶桉、广东凤丫蕨、柳叶竹、大叶相思、青皮、木荷、湿地松在内的7种南亚热带不同植物植被下土壤根际微生物与根际养分状况及其相关关系。结果表明,根际环境对细菌有明显的正效应,对放线菌和真菌有正、负两方面的影响,但对根际微生物总量具有根际效应明显;在南亚热带森林生态系统中,在植物的某些生长季节,微生物的根际效应与土壤养分的根际效应一致。 相似文献
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山西省玉米根际固氮特性研究 总被引:1,自引:0,他引:1
玉米根际固氮活性随品种和生态条件的不同而变化,在山西土壤气候条件下,测试品种中有91.7%具有固氮活性,变异系数为62.8%,固氮高出现在抽雄期,大约每公顷年固氮量8.1kg。在一定条件下,秸秆覆盖栽培,增施有机肥、磷肥、少量氮肥以及人工接种均有利于提高玉米根际的固氮作用。 相似文献
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VA菌根真菌对玉米生长及根际土壤微生态环境的影响 总被引:16,自引:0,他引:16
用两种不同的VA菌根真菌Glomus mosseae和Glomus caledonium接种玉米进行盆栽试验。结果表明,两种菌株均能侵染玉米,促进玉米生长,其中以Glomus caledonium的侵染率和作用较为明显。接种后,根区土壤中的细菌、放线菌、固氮菌的数量和微生物量明显增加,但真菌的数量则稍有下降。此外,菌根的形成也改善了根区土壤的微生态环境,为下一造作物的生长积累了养分基础。 相似文献
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关于淹水条件下根际效应的研究迄今很少。而淹水土壤的根际环境与早作土壤十分不同。 相似文献
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为揭示根-土界面微域养分的吸收、累积与亏缺状况,运用X-射线电子探针研究盐胁迫对白蜡根际和根内营养元素相对含量及其分布的影响。结果表明,与对照(0 g/L)相比,低浓度(3 g/L)盐分处理使白蜡根系吸收较多的Ca、Mg、Cl等元素; 而高浓度(9 g/L)处理则使根系吸收Ca、Mg、Cl的能力下降。白蜡根内Na、K、Fe的累积量和根际Na的含量随盐浓度增加均有升高; 其中,过量的Na会破坏白蜡根细胞原生质膜的结构,引起胞内营养大量外泌,造成植物营养缺乏,从而诱发盐害。因此,Na在根际微域的累积是引起白蜡盐害的主要原因。 相似文献
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间套作玉米对线辣椒根际土壤微生物生态特征的影响 总被引:4,自引:0,他引:4
采用常规稀释平板法、氯仿熏蒸法、BIOLOG GN微平板反应系统及种间根系分隔技术, 以线辣椒单作(SC)为试验对照, 研究了间套作处理[玉米/线辣椒套作+根部塑料膜分隔(ICP)、玉米/线辣椒套作+根部尼龙网分隔(ICM)、玉米/线辣椒套作根部无分隔(ICN)]对线辣椒根际土壤微生物生态特征的影响。结果表明: 整个线辣椒生育期内, 各套作处理线辣椒根际土壤微生物总数与细菌总数具有相同的变化趋势, ICN和ICM处理的真菌、细菌、放线菌数量和细菌/真菌(B/F)、放线菌/真菌(A/F)比值均大于ICP与SC处理。盛果期, ICN处理根际土壤微生物量碳和微生物量氮比同处理其他生育期增加14.2%~54.0%和10.6%~54.7%。各处理土壤微生物群落AWCD的变化随培养时间呈现明显的"S"型曲线。间套作玉米显著提高了线辣椒根际土壤微生物群落的Shannon-Wiener指数(P<0.05)、Simpson指数、种间相遇几率和McIntosh指数(P<0.05), 并改变了土壤微生物对单一碳源的利用能力。线辣椒根际土壤微生物的不同多样性指数分别与其生物学产量之间存在显著或极显著正相关。说明间套作改善了土壤微生态环境。 相似文献
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为了解西南地区玉米施肥现状与养分管理存在的问题,对西南地区4个省10个县的202份玉米养分调查数据进行了分析和评价。结果表明:(1)西南地区玉米生产中基肥以复合(混)肥为主,追肥以尿素和复合(混)肥为主;有机肥、玉米专用肥、缓(控)释肥等新型肥料使用率低。(2)化肥N、P_2O_5和K_2O平均投入量分别为323.52、80.93和56.55 kg·hm~(-2),总体表现为氮肥过量和钾肥不足,氮肥超量施用比例为62.38%,钾肥施用不足比例为60.89%,且区域之间差异较大。(3)玉米基肥以穴施覆土为主,但追肥养分管理粗放,第1次和第2次追肥中采用穴施不覆土的农户比例分别为63.22%和59.76%,表土撒施的比例分别为10.34%和25.61%。建议分区域明确玉米氮肥投入限量标准,引导农户降低氮肥用量;增施有机肥,发挥养分替代效应,同时推行秸秆还田,补充土壤钾素,提高土壤持续生产能力;推进玉米机械化生产,实现种、肥同播和化肥深施,降低农田养分流失。 相似文献
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Accelerated mineralisation of atrazine in maize rhizosphere soil 总被引:4,自引:0,他引:4
S. Piutti S. Hallet S. Rousseaux L. Philippot G. Soulas F. Martin-Laurent 《Biology and Fertility of Soils》2002,36(6):434-441
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山西省菜田土壤养分状况及主要蔬菜的平衡施肥 总被引:10,自引:5,他引:10
在山西省10个市60多个县(市)的7333hm2菜田耕层取土样1086个,分析测定了土壤有机质、全N、碱解N、速效P、速效K、有效B、Mn、Mo、Zn、Fe、Cu等养分含量;开展了不同肥力菜田主要蔬菜的平衡施肥试验共120余次;提出了山西省5种主要蔬菜在不同肥力菜田上的推荐施肥量。 相似文献
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Anne-Laure Marchand Séverine Piutti Bernard Lagacherie Guy Soulas 《Biology and Fertility of Soils》2002,35(4):288-292
An experiment was carried out in the greenhouse in order to compare atrazine mineralization in bulk soil and maize rhizosphere at different development stages. After 4, 8 and 12 weeks, we have (1) measured the soil microbial biomass C, (2) characterized the C substrate utilization profiles of the culturable microflora, and (3) analyzed atrazine mineralization. Microbial growth was stimulated in planted soil and different C substrate utilization patterns were obtained in bulk and rhizosphere soils during the first 2 months. During this period, laboratory tests for atrazine biodegradation revealed a lower mineralization potential in bulk than in planted soil. Atrazine mineralization was stimulated to a greater extent after atrazine application in the greenhouse but again the presence of plants had a favorable effect. After 12 weeks of cropping, the atrazine mineralization potential decreased in planted soil with or without prior atrazine application. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(5-6):679-693
Abstract The volcanic ash of the Mount Pinatubo in Philippines was used in this study. The major drawbacks of this ash for growing agricultural crops are nitrogen (N) and iron (Fe) deficiencies with low organic matter contents. The main objective of this study is to investigate the wheat grown on the volcanic ash to and determine the nutrient status across its rhizosphere using a rhizobox system. Either oxamide or polyolefinresin‐coated urea (PORCU) along with potash and phosphate fertilizers was applied to each rhizobox containing the volcanic ash. Plants were grown on the central compartment (CC) of the rhizobox. The nutrient status was examined by the assessment of distribution patterns of NH4 +‐N, NO3 ‐‐N, Ca2+, Mg2+, K+, Cl‐, SO4 2‐, PO4 3‐, and associated pH. Although NH4 +‐N in both oxamide and PORCU treatments was accumulated to a somewhat considerable extent of the rhizosphere. The rhizosphere effect was more prominent in oxamide treatment. While NO3 ‐‐N concentrations in either of the treatment was low with a mere rhizosphere effect in PORCU treatment and a rugged distribution in oxamide treatment. Dominant anions and cations accumulated in the CC and the near by compartments of oxamide treatment were Cl‐, SO4 2‐ and Ca2+, respectively. In contrast, SO4 2‐ and K+ were accumulated in the CC and the adjacent PORCU treated compartments. Thus the overall distribution of nutrients and pH across the wheat rhizosphere was rugged. Despite of this, it seems that with a rugged nutrient distribution and pH, the effects of slow releasing N fertilizers may well ensure the N benefit on plants while growing on the volcanic ash under circumstances of low N content. 相似文献
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The interaction between the roots of Zea mays L. and its rhizosphere microflora was studied in nutrient solution with respect to two exemplary aspects - water soluble vitamins and the four most frequent carbohydrates. The exudation of vitamins and sugars into the medium is increased in a solid substrate (glass-ballotini simulating soil structure) in comparison with nutrient solution only. The amounts of vitamins released (1 to 421 ng per plant) are high enough for a pronounced influence on the rhizosphere microflora to be expected. However, the microbial population feeding on the exudates has very simple nutritional demands. In spite of appreciable amounts of vitamins found in the inoculated nutrient solution, the growth of vitamin requiring species is not stimulated compared to the soil population. The roots are mostly inhabited by shorter rods and occasionally by actinomycete-like filaments. The percentage of the root area covered by its microflora, assuming a monolayer, is 4% in the root region where root hairs are just emerging, 7% in the root hair zone and 20% in the oldest part of the roots, 10 mm below the grain. In the presence of rhizosphere microorganisms, root dry weight is lower than that of axenically grown plants because the diameter of the primary root is diminished. In addition, the vitamin and sugar content of the root is affected by rhizosphere microorganisms. The results can be interpreted as an indication that phytohormones may participate in interactions between roots and bacteria. 相似文献
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水稻根际氮素状况及其利用 总被引:2,自引:0,他引:2
A greenhouse pot experiment was conducted with hybrid rice(Oryza Sativa L.) in order to study N Status and utilization in the rhizosphere of rice,The experiment was composed of three treatments:without N,15NH4-N and 15NO3-N .Plant roots were separated from the soil by a nylon cloth,and 1 mm increments of soil,moving laterally away from the roots,were taken and analyzed for various N froms.The labelled N in the plants ranged from 67\51%to 69.24% of the total amount of N absorbed by the rice seedlings with the labelled fertilizer N treatments.This shows that the N in the Plants came mainly from the fertilizers.However,the N absorbed by the rice seedlings accounted for less than 35% of the total amount of the N depletion in the soil near the rice roots,indicating an important N loss in the rhizosphere of rice.The soil redox potential(all treatments)and the concentration of the labelled NO3-N(the labelled NH4-N treatment only) decreased as the distance from the rice roots increased in the rhizosphere of rice.In contrast,the concentration of the labelled NH4-N increased as the distance uincreased in the same soil zone.These results suggested that nifrification occurred in the soil around the rice roots.Therefore,the reason for the N loss in the rhizosphere of rice might be the NO3 movement into the reductive non-rhizosphere soil(submerged) where denitrification can take place. 相似文献
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冬小麦-夏玉米轮作体系中不同施氮水平对玉米生长及其根际土壤氮的影响 总被引:12,自引:3,他引:12
在河北衡水潮土上进行田间试验,以当地习惯高氮用量(小麦季施N 300 kg/hm2,玉米季施N 240 kg/hm2)为对照,研究冬小麦-夏玉米轮作体系中减少氮肥用量对玉米季植株生长、氮素吸收及根际土壤中无机氮与微生物量氮的影响。结果表明,两季作物氮肥施用量减少25%和40%,对玉米产量、生物量及植株体内氮累积量未产生明显影响,氮肥利用率提高。不同氮肥施用量对根际和非根际土壤铵态氮含量的影响不显著;减少氮肥施用量,对玉米根际土壤硝态氮含量也没有明显影响。在玉米苗期、抽雄期和成熟期,习惯高施氮量处理的非根际土壤硝态氮含量较高,其中抽雄期,非根际土壤硝态氮含量较氮肥减施40%用量处理高出近一倍,但非根际土壤微生物量氮水平含量明显降低。氮肥减施未影响根际土壤微生物量碳、氮含量,反而增加了非根际土壤微生物量碳、氮水平。在高肥力的潮土上,冬小麦/夏玉米轮作体系中适当减施氮肥并未影响玉米根际土壤氮素水平,可保证玉米稳产,实现减氮增效。 相似文献