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博尔塔拉河下游河岸带土壤养分特征及其相关性分析 总被引：2，自引：0，他引：2
对博尔塔拉河下游河岸带土壤有机质、全氮、速效磷、速效钾、pH进行了分析。结果表明：① 土壤有机质在表层和80 cm土层属于强变异;20 cm、40 cm和60 cm土层属于中等变异。② 有机质含量为0.03%～4.19%,差值较大;不同深度土壤有机质含量从表层到深层逐渐减少,递减规律显著;5层（0~10 cm、20 cm、40 cm、60 cm和80 cm）土壤之间有机质含量垂直方向的相关性特征显示,60 cm深度与其他层次土壤有机质含量呈弱正和弱负相关,0 cm与80 cm、20 cm与40 cm之间的相关性极显著。③ 土壤有机质含量与pH、速效钾含量呈负相关,与速效磷含量呈正相关,与全氮呈极显著正相关（[WTBX]R[WTBZ]=0.934）。④ 通过对土壤样品养分含量分级显示,土壤有机质含量和速效磷含量平均值分别为0.44%和1.99 mg•kg-1,均属于极缺乏型;全氮含量和速效钾含量平均为0.07%和39.78 mg•kg-1,属于很缺乏型;pH平均为7.47,属于中性。 相似文献
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乌兰布和东北部典型土地利用的土壤养分特征 总被引：1，自引：0，他引：1
采用野外实地调查采样、室内样品分析相结合的方法,研究了乌兰布和沙漠东北部3种不同利用类型土地（耕地、林地、荒漠灌丛）的土壤养分特征,并对土壤肥力进行了综合评价。结果表明：研究区有机质含量、全氮、全钾、全磷分别为8.02±4.35、0.34±0.14、0.37±0.09、16.10±2.04 g·kg-1,碱解氮、速效磷、速效钾分别为18.48±8.27、3.76±0.89、135.04±83.35 mg·kg-1,pH值为8.8±0.20; 土地利用方式对有机质、全磷、碱解氮、速效磷、速效钾、pH值影响显著（P＜0.05）,对全氮、全钾影响不显著（P＞0.05）; 三种土地利用方式下土壤有机质、土壤全氮、碱解氮、全磷、速效磷、全钾、速效钾随着土层深度的增加呈下降趋势; 土壤肥力综合评价的排序为荒漠灌丛(0.443)＞林地(0.409)＞耕地(0.312), 荒漠灌丛与林地的土壤肥力为中等级水平,而耕地的肥力为低等级水平。荒漠灌丛与林地比耕地有利于土壤保肥。 相似文献
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新疆艾比湖湿地自然保护区土壤空间异质性研究 总被引：10，自引：1，他引：9
通过对新疆艾比湖湿地自然保护区内土壤颗粒组成、水分、盐分、pH值和速效养分(氮、磷、钾)、有机质含量等土壤理化性状的空间分宜进行了探讨。结果表明:土壤颗粒组成主要以粉粒与砂粒为主,土壤质地以粉砂质壤土与砂质壤土为主;土壤含水量总体呈现湖周湿地>河流入湖口>泉眼分布区>荒漠的规律;艾比湖湿地不同类型土壤盐分存在明显的表聚现象,土壤盐化、碱化严重;艾比湖湖周土壤pH值北部高于南部,东部高于西部;艾比湖东部土壤速效氮含量最低,南部速效钾含量最低,北部速效磷含量最低,与此同时,艾比湖湿地速效养分在不同土壤类型不同剖面中的含量具有一致性;土壤有机质与碱解N含量相关性较强,其空间分布的特点是环湖土壤有机质含量低于阿其克苏河沿岸土壤有机质含量,梭梭荒漠表层及平均有机质含量与土壤含水量呈弱线性相关。 相似文献
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选取16个当地种植的马铃薯品种进行试验,采取单因素分析法和冗余分析法对榆林沙土区马铃薯田的土壤含水量、pH值、电导率、碱解氮、有效磷、速效钾、有机质含量和过氧化氢酶、脲酶、蔗糖酶活性,以及土壤细菌、真菌、放线菌数量进行研究,分析其特征。结果表明：在0~60 cm土层中,榆林沙土区马铃薯根层土壤过氧化氢酶和脲酶活性随着土壤深度的增加均呈现降低的趋势,土壤蔗糖酶活性随土壤深度的增加呈现先增大后降低的趋势, 0~20 cm土层过氧化氢酶活性比20~40、40~60 cm土层分别高0.03％、28.74％,0~20 cm土层脲酶活性比20~40、40~60 cm土层分别高14.10％、169.70％,20~40 cm土层蔗糖酶活性比0~20、40~60 cm土层分别高21.74％、59.53％;在0~40 cm土层中,随土壤深度的增加土壤细菌、真菌、放线菌数量均呈现降低的趋势,细菌数量在3类微生物中占有绝对优势,占微生物总数的83.11％~97.28％,其次是放线菌,占微生物总数的2.49％~16.49％,真菌的数量最少,占微生物总数的0.13％~0.44％;不同品种马铃薯根层（0~60 cm）土壤含水量、pH值、电导率分别为2.94%~8.00％、8.30~8.79、101.92~210.87 μS·cm-1,碱解氮、有效磷、速效钾、有机质的含量为16.47~30.14 mg·kg-1、15.37~25.49 mg·kg-1、95.83~163.60 mg·kg-1、2.85~5.43 g·kg-1。相关性分析表明,马铃薯根层土壤过氧化氢酶、脲酶、蔗糖酶活性均与土壤碱解氮、有机质含量呈极显著正相关(P＜0.01);土壤细菌、真菌、放线菌均与土壤有机质、有效磷、速效钾呈极显著正相关(P＜0.01);马铃薯块茎产量与土壤细菌呈极显著正相关(P＜0.01),块茎可溶性总糖与土壤放线菌呈显著正相关(P＜0.05)。冗余分析表明,碱解氮和有机质是土壤过氧化氢酶和脲酶活性变化的主要驱动因子,有机质和有效磷是土壤细菌数量变化的主要驱动因子,速效钾是土壤真菌、放线菌数量变化的主要驱动因子。 相似文献
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粉痂病严重影响马铃薯的产量和品质,是我国马铃薯产业健康发展的重要制约因素之一。为进一步探明马铃薯粉痂病在云南省的发生、分布及危害情况,本研究于2018年-2019年,在云南省内马铃薯不同生态种植区,开展了马铃薯粉痂病的发生与危害情况调查。调查范围涉及19个县(区)、涵盖了19个当地马铃薯主栽品种(系)。调查结果显示:粉痂病在云南发生普遍,发病率在0%~51.72%,平均发病率和病情指数分别为15.01%和5.32。其中春作区马铃薯粉痂病的发生较为普遍,平均发病率为25.08%,病情指数为8.24。冬作区马铃薯粉痂病在部分产区有发生,平均发病率为4.93%,病情指数为2.39。与2004年-2008年云南省粉痂病调查数据相比,粉痂病发病率下降,病害有所减轻。 相似文献
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以农田、露天菜地为对照,研究了山西阳高连作1、4、7、11、14、17 a设施栽培土壤pH值、养分含量及其相互关系。结果表明,与农田相比,设施栽培菜地土壤pH值降低、养分含量升高,差异达显著水平。随种植年限增加,设施内0~20 cm、20~40 cm土层有机质、碱解氮、有效磷含量表现出先升高后降低的趋势。依据设施菜地土壤养分含量标准,阳高设施土壤pH值、有机质、速效钾含量处于适宜水平,碱解氮含量较高,有效磷严重超标。相关分析表明,土壤pH值与速效钾含量间呈显著负相关,各土壤养分含量间呈显著正相关。当地设施蔬菜生产中的不合理施肥,已导致土壤化学性状发生明显变化,今后应推广科学施肥。 相似文献
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艾比湖湿地泥炭土壤养分特征分析 总被引：2，自引：0，他引：2
以新疆艾比湖湿地泥炭土壤为研究对象,结合分析化学的手段,对泥炭土壤中的有机质、碱解氮、速效钾、有效磷等养分含量、空间分布特征进行测定与统计分析。结果表明:土壤有机质、碱解氮含量呈现出较强的表聚性,养分含量中有机质含量较高;其它养分含量较低;泥炭土壤中表层土壤有机质与碱解氮、速效钾、有效磷存在显著相关性,泥炭深层土壤的有机质与碱解氮、有效磷相关性较强;空间变异特征显示,土壤各养分指标均表现为中等空间变异特征。 相似文献
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豫西低山丘陵区不同土地利用方式对陡坡地土壤理化性状的影响 总被引：1，自引：0，他引：1
对豫西低山丘陵区陡坡地5种土地利用方式(人工草地、自然荒草地、柏树林地、人工女贞林地和桃树林地)下土壤部分理化性状对土地利用变化的响应进行了比较研究。结果表明,人工干扰活动会加速陡坡地土壤质量退化。5种土地利用方式间土壤理化指标除速效磷含量外均呈显著性差异（P＜0.05）,近自然状态的柏树林土壤有机碳、全氮、碱解氮、C/N、全磷、速效磷、速效钾含量和土壤电导率均最高,全钾含量也较高,仅次于人工草地,pH值接近于7;人工草地、人工女贞林地有机碳、全氮、碱解氮、全磷含量和土壤电导率较低,与其他用地方式间差异显著（P＜0.05）。陡坡地植被郁闭度和盖度对土壤全钾含量的影响较大,林地速效钾含量高于草地。因此,在豫西低山丘陵区35°以上陡坡地不宜作为人工草地和人工景观林地,建议将柏树作为生态恢复的优先选择树种。 相似文献
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Root infection of potato by Spongospora subterranea: knowledge review and evidence for decreased plant productivity 
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下载免费PDF全文 R. E. Falloon U. Merz R. C. Butler D. Curtin R. A. Lister S. M. Thomas 《Plant pathology》2016,65(3):422-434
Information is reviewed on root infection of potato by the plasmodiophorid Spongospora subterranea f. sp. subterranea. This pathogen has long been recognized as the cause of root galls (hyperplasia) and the economically important disease powdery scab on tubers (modified stolons). The significance for plant productivity of the zoosporangium stages of the pathogen in potato roots has only recently begun to be documented. Two experiments are described that assessed effects of S. subterranea root infection on potato plant root function and productivity. A greenhouse experiment measured root function and plant parameters for eight potato cultivars with markedly different susceptibilities to tuber powdery scab. Water uptake and plant growth were reduced by S. subterranea inoculation in all eight cultivars. The magnitudes of these negative effects, and intensities of root hyperplasia, differed among the cultivars, but were not related to respective susceptibilities to tuber powdery scab. A field trial assessed root function and plant productivity for a cultivar (Iwa) that is very susceptible to Spongospora tuber and root diseases. Soil water content beneath uninoculated plants was consistently less than for inoculated plants, indicating that inoculation reduced water uptake (root function). Inoculation reduced shoot and root dry weights, and reduced weight of tubers per plant by 42%. Spongospora subterranea causes three diseases of potato: root membrane dysfunction, root hyperplasia and tuber powdery scab. The root diseases caused by the pathogen are likely to be important both for powdery scab management and for deleterious effects on potato crop yields. 相似文献
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The effects of soil inoculum level and three environmental factors (soil type, soil moisture regime and temperature) on the incidence and severity of powdery scab caused by Spongospora subterranea were investigated in potato plants grown under controlled environmental conditions. Symptoms of powdery scab on tubers were assessed visually, after which DNA was extracted from tuber peelings and quantified in a real-time polymerase chain reaction assay using primers and a TaqMan® probe specific to S. subterranea to establish tuber infection levels. Soil inoculum concentration of S. subterranea did not significantly affect the incidence and severity of either tuber infection or powdery scab symptoms at maturity. No significant differences in disease incidence and severity were found between sandy, loamy and clay soils, although the two lighter soils yielded more powdery scab than clay soil. Constant dampness of the soil resulted in significantly more disease than a fluctuating moisture regime. Infection and disease levels were high at all three temperatures tested (9, 12 and 17°C), but symptoms were most severe at 12°C. The percentage of plants with infected tubers did not increase after tuber initiation, although the amount of S. subterranea DNA detected in tubers and the severity of powdery scab symptoms increased in mature plants. Latent tuber infections were found to be common, especially under conditions suboptimal for disease development. This new information may be important for the prevention of powdery scab in potato-growing areas around the world. 相似文献
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U. Merz A. K. Lees L. Sullivan R. Schwärzel T. Hebeisen H. G. Kirk K. Bouchek‐Mechiche H. R. Hofferbert 《Plant pathology》2012,61(1):29-36
Powdery scab of potato caused by Spongospora subterranea is one of the main disease problems in many potato production regions of the world. However, no efficient and economically sound control method is currently available. Host resistance will be a key component of the integrated management of powdery scab, but there are discrepancies in published powdery scab resistance ratings of cultivars between countries. In order to identify the main factors causing such discrepancies, 10 reference cultivars thought to have a range of susceptibility to powdery scab and potato mop‐top virus were cropped over 4 years in four to six locations across Europe and disease levels on roots and tubers were assessed using standardized scoring scales. Soil contamination was tested using real‐time PCR and ELISA. The cultivars performed as expected according to previous characterization, with one exception. No relationship was found between tuber and root susceptibility. Assessment of powdery scab symptoms 1 month before harvest gave results comparable to those assessed 2 months after harvest. Neither real‐time PCR nor ELISA soil test results were closely related to disease index data. The field trial results indicate that different scoring methods are the main factor for the discrepancy in resistance ratings, and that environmental conditions and/or soil inoculum level play a minor role. Furthermore, there was either no difference between the pathogen populations in each location or the resistance of most of the cultivars is polygenic. 相似文献
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Variant somaclones of potato cultivar Russet Burbank, selected for resistance to common scab using in vitro cell selection techniques, were tested for resistance to powdery scab, another important disease of potato caused by Spongospora subterranea. This pathogen also invades roots, producing root galls. Most variants consistently showed increased resistance to powdery scab, both in field and glasshouse challenge, when compared to the parental cultivar, several significantly so. On average, the best variant reduced powdery scab incidence by 51% and severity (tuber surface coverage) by 64%. In contrast, no improvement in the extent of root infection and root galling was seen. These results suggest host interactions during root and tuber infection are distinct. Correlation analyses of disease indices amongst the selected variants showed no association between Sp. subterranea root infection and gall scores, nor between root infection and tuber disease severity. However, a weak positive association was found between root gall score and tuber disease, and a strong correlation between tuber disease incidence and severity scores. Interestingly, positive correlations were also found between the extent of powdery and common scab resistance expressed and both incidence and severity of these diseases within the variants, suggesting a common defence mechanism. The role of thaxtomin A in selecting for concurrent resistance to both diseases is discussed. 相似文献
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Potato mop-top virus (PMTV) causes disease in both the growing plant and tubers (spraing) of potato and is transmitted by the plasmodiophorid Spongospora subterranea , the cause of powdery scab. The effect of temperature during plant growth on the transmission of PMTV from infected seed tubers and from infested growing media was investigated in a series of glasshouse experiments. Symptoms developed on foliage of plants derived from infected seed tubers but none developed when PMTV was transmitted by S. subterranea in soil. The incidence of foliar symptoms was greatest on plants grown at 12°C, less at 16°C, few at 20°C and absent at 24°C. The transmission of PMTV from infected seed tubers was not significantly affected by temperatures between 12 and 24°C, but when the virus was transmitted by S. subterranea , minimal tuber infection occurred at 24°C and no differences were recorded at temperatures between 12 and 20°C. The incidence of powdery scab on tubers was greatest at 12 and 16°C and very low at 20 and 24°C. However, the incidence and severity of root galling caused by S. subterranea , was greatest at 20 and very low at 24°C. The incidence of powdery scab was greater on tubers of plants derived from infected seed tubers grown in a fluctuating temperature regime of 12 h at 20°C followed by 24 h at 12°C than on those grown at a constant 20°C, whereas the incidence of tuber infection by PMTV and spraing was similar for both regimes. This demonstrates that infection of roots can occur at a higher temperature than that for powdery scab on tubers and that this root infection can enable the transmission of PMTV into the potato plant. 相似文献
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This study was undertaken to determine the current occurrence in Scottish seed potato crops of Potato mop‐top virus (PMTV), which is transmitted by Spongospora subterranea and causes spraing (brown arcs and lines) in the flesh of potato tubers, rendering them unsaleable. In 2004, a stratified survey of four commonly grown cultivars was conducted, while in 2007 and 2008, only samples from powdery scab‐affected crops were collected. The incidence of crops in which infection by PMTV was present was 37·5% in the stratified survey in 2004, but was greater in surveys in which tubers with powdery scab were tested (47·2% in 2007 and 44·6% in 2008). Similarly, the frequency of crops with incidences of more than 10% tuber infection was lower (9·4%) in 2004 than in 2007 (25·4%) and in 2008 (26·2%). Significant differences in crop infection were found amongst the four major seed‐producing regions and the counties within these regions. The incidence of crop and tuber infection was least for class Pre‐basic seed potatoes and greatest for class Super Elite 3 and Elite seed potatoes. The results indicate that the prevalence of PMTV has not increased since surveys in the early 1970s. 相似文献
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U. Merz V. Martinez R. Schwärzel 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(1):71-77
Powdery scab of potato, once established in a field, is difficult to control because of the longevity of the resting spores (cystosori) of the causal organism, Spongospora subterranea f.sp. subterranea. Host resistance is likely to be the most efficient in a long-term control strategy for preventing build-up of field inoculum and spread of the disease. Resistance screening of potato cultivars is mostly done in laborious field trials where disease development is likely to be unpredictable. A bioassay with potato tissue cultured plantlets and cystosori as inoculum is described and was tested for its potential to screen potato cultivars at an early stage for their relative susceptibility to powdery scab by comparing the lab results with field data. With cystosori inoculum of Swiss origin, the laboratory test showed clear differences between the potato cultivars in the severity of zoosporangial root infection which correlated better with ranked tuber infection data, compared to root galling. There are apparent differences in the relative trends in susceptibility between roots and tubers of five selected cultivars when using naturally infested soil instead of prepared cystosori as inoculum in the lab bioassay. Furthermore, differences in the severity of zoosporangial root infection of two selected cultivars were found when cystosori from different countries where used as inoculum. A possible host genotype × pathogen interaction is discussed. The bioassay has the potential to screen and select for resistant material at an early breeding stage thus making field trials not unnecessary but more economical. It will allow the use of a standard set of pathogen collections and facilitate testing for inoculum virulence in infested soils. 相似文献
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Common and netted scabs are two disfiguring bacterial diseases of potato tubers, caused by various groups of Streptomyces species. Common scab, caused primarily by Streptomyces scabies and Streptomyces europaeiscabiei , is characterized by more or less deep pustules on the tuber surface, while symptoms of netted scab, caused mainly by Streptomyces reticuliscabiei , are superficial, corky alterations of the tuber periderm. Some isolates of S. europaeiscabiei are able to induce both common and netted scab symptoms, and therefore constitute a third pathogenicity group. Like most bacterial diseases, potato scabs would be best controlled by using resistant cultivars. Repeated experiments with soil artificially infested with isolates of three species representative of the three pathogenicity groups showed the level and stability of cultivar resistance, as well as the existence of a range of aggressiveness among different isolates. The distribution of scab severity indexes recorded on a collection of 16 potato cultivars and 27 breeding clones grown in soil infested with common scab-inducing isolates was continuous, suggesting isolate nonspecific quantitative resistance. Least susceptible cultivars were Nicola, BF15, Sirtéma, and Charlotte, while Urgenta, Désirée, Ondine and Bintje were very susceptible. The same genotypes proved either highly susceptible (e.g. cvs Bintje, Désirée or Carmine) or highly resistant (e.g. cvs Charlotte, Sirtéma, Monalisa, BF15 or Belle de Fontenay) to isolates forming netted scab symptoms, suggesting isolate-specific qualitative resistance. The ability was confirmed of some isolates of S. europaeiscabiei to induce one or the other type of symptoms depending on cultivar and soil temperature. 相似文献
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J. L. Brierley L. Sullivan S. J. Wale A. J. Hilton D. T. Kiezebrink A. K. Lees 《Plant pathology》2013,62(2):413-420
The relationship between initial soil inoculum level of Spongospora subterranea f. sp. subterranea (Sss) and the incidence and severity of powdery scab on potato tubers at harvest was investigated. In all experiments soil inoculum level of Sss (sporeballs/g soil) was measured using a quantitative real‐time PCR assay. Of 113 commercial potato fields across the UK, soil inoculum was detected in 75%, ranging from 0 to 148 Sss sporeballs/g soil. When arbitrary soil inoculum threshold values of 0, <10 and >10 sporeballs/g soil were set, it was observed that the number of progeny crops developing powdery scab increased with the level of inoculum quantified in the field soil preplanting. In four field trials carried out to investigate the link between the amount of inoculum added to the soil and disease development, disease incidence and severity on progeny tubers was found to be significantly (P < 0·01) greater in plots with increasing levels of inoculum incorporated. There was a cultivar effect in all years, with disease incidence and severity scores being significantly greater in cvs Agria and Estima than in Nicola (P < 0·01). 相似文献