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1.
本文研究了乌兰察布高原的地带性土壤府殖质的地理分布规律：（碱溶性腐殖质可提取的部分）以深厚黑色土为最高：８０－８７％；向北过渡至栗钙土、棕钙土明显降低在２０％左右，ＨＡ／ＦＡ亦是以深厚黑色土最高：土层中部达２以上；栗钙土１－１．５；至棕钙土０．６－１，并且表层最高，下部土层减少＜１；山地土壤ＨＡ／ＦＡ最高层在Ａ１层：１－１．３左右，向下锐减。光密度特性Ｅ４：Ｅ６：深厚黑色土最小＜４；草原土壤在４－５；山地土壤：＞５。土壤Ｃ／Ｎ也反映了土壤类型之间差异：深厚黑色土：表层低：６－７，下层高：１２－１３；草原土壤多在９－１０；山地土壤则较大１１－１３。通过对土壤以上各化学指标分析研究，明确了土壤类型的划分依据，对本区土壤分类中存在的几个问题进行初步探讨。 相似文献
2.
土壤侵蚀成因机制分析与模拟 总被引：3，自引：0，他引：3
本文对黄土丘陵沟壑区土壤侵蚀的成因机制与运动机理进行了深入探讨，分析了黄土地区高含沙火流通人的形成及其汇流过程，讨论了泥沙运动的基本模式。在此基础上对高含沙水流的运动机理及其挟沙力进行了力学模拟，分析了高含沙水流的流速分布及泥沙的垂线分布，构造了推移质泥沙的输沙模型。 相似文献
3.
D. L. EBBELS 《Plant pathology》1983,32(2):145-150
Seed potato tuber inspections were inaugurated in England and Wales as a training exercise daring 1974–77, preparatory to the operation of seed potato classification under statutory authority as from 1978. The number of stocks inspected varied from 359 for the 1976 harvest (38% of those classified) to 536 for the 1975 harvest (52%). The proportion of stocks meeting the required standards progressively increased from 82% for 1974 crops to 91% for 1977 crops. The diseases most commonly causing the failure of stocks to meet the required standards were gangrene ( Phoma exigua var. foveata ) for crops harvested in 1974, 1975 and 1977, and non-bacterial soft rots for 1976 crops. Over the 4 years the proportion of stocks failing to meet the required standards for diseases were respectively: 1.2% for tuber blight ( Phytophthora infestans ); 0.6% for bacterial soft rots ( Erwinia carotovora subspp.); 2.0% for non-bacterial soft rots (including Phytophthora erythroseptica and Pythium ultimum ); 0.8% for dry rots ( Fusarium spp.); 4.0% for gangrene; 0.1% for skinspot ( Polyscytalum pustulans ); 0.1% for black scurf ( Rhizoctonia solani ); 0.1% for powdery scab ( Spongospora subterranea ) and 1.6% for common scab ( Streptomyces spp.). 相似文献
4.
为评估草地贪夜蛾Spodoptera frugiperda对国产Bt玉米的抗性风险,基于抗性风险分析模型对草地贪夜蛾在3种Bt玉米和2种庇护所条件下的抗性时间进行预测分析。结果显示,无论是采用种子混合庇护所还是结构化庇护所,草地贪夜蛾对Cry1Ab+Vip3Aa-玉米的抗性时间均远长于对Vip3Aa-玉米和Cry1Ab-玉米的抗性时间。在Bt与非Bt植株之间存在异花授粉和幼虫转移的条件下,采用种子混合庇护所的抗性时间较采用结构化庇护所的抗性时间大大缩短。以采用Cry1Ab+Vip3Aa-玉米和比例为0.20的庇护所为例,当异花授粉Bt显性度为0.5、幼虫转移概率为0.95时,采用结构化庇护所的抗性时间超过200代,而采用种子混合庇护所的抗性时间只有59代。结果表明,草地贪夜蛾对Cry1Ab-玉米的抗性风险远大于对Cry1Ab+Vip3Aa-玉米的抗性风险,而种子混合庇护所条件下的抗性风险远大于结构化庇护所条件下的抗性风险。 相似文献
5.
The rates of spontaneous regeneration or decarbamylation of fly-head and bovine erythrocyte cholinesterase inhibited by methyl- and dimethylcarbamic acid esters were determined under different conditions of pH, salt concentrations, and temperature using Sephadex gel filtration as a means of isolating the carbamylated enzyme. The pH-rate profiles for decarbamylation of the two cholinesterases for both methyl- and dimethylcarbamylated enzyme had maximum rates at pH 8.5–8.9 for bovine erythrocyte and pH 8.1–8.5 for fly-head cholinesterase. Imidazole, hydroxylamine, and inorganic salts did not alter the decarbamylation rate. Values for the energy of activation for the decarbamylation reaction indicate a somewhat unstable and more reactive carbamylated enzyme for bovine cholinesterase compared to fly-head cholinesterase, but entropy factors are more favorable for decarbamylation in the latter. Regeneration rates in deuterium oxide for both enzymes and both methyl- and dimethylcarbamates were approximately six to seven times slower than in water, indicating a secondary isotope effect. A mechanism for decarbamylation consistent with the data is cited. 相似文献
6.
奈曼旗沙漠化地区农业生态系统能流效益特征分析 总被引：3，自引：0，他引：3
本文探讨了奈曼旗沙漠化地区农业生态系统的能流效益,指出了该区农业生态系统能量总投入产出比为3.67;总产出能与商品能之比为12.72;总产出能与有机能之比为8.47;总产出能与机械能之比为13.22。并对该区11个农业子系统进行了综合评价。 相似文献
7.
E. Muller 《EPPO Bulletin》2007,37(1):215-218
The availability of plant protection products that are authorized for minor uses in the European Community is becoming restricted due to the stringent EU review process. An associated problem is the lack of sufficient residues data for minor uses necessary for the establishment of MRLs (Maximum Residue Levels). The policy for MRL setting is focussed on a high protection level for the consumer. Good Agricultural Practice (GAP) forms the basis for MRL setting together with supervised residues trials according to GAP. The MRL can be set when risk assessment shows no risk for the consumer. Rules to extrapolate residues data from major crops to minor crops can sometimes be derived from, for example, morphological properties of the crop, provided the GAP is similar, but for many minor crops this is not possible. In these cases residues trials performed on the minor crop are required to set an MRL, however, performing residues trials is not profitable for the plant protection industry, because of their limited financial return. Activities to facilitate the setting of MRLs for minor crops have been initiated both within the EU and CODEX. 相似文献
8.
A general multi-objective programming model for minimum ecological flow or water level of inland water bodies 总被引：1，自引：0，他引：1
SongHao SHANG 《干旱区科学》2015,7(2):166-176
Assessment of ecological flow or water level for water bodies is important for the protection of degraded or degrading ecosystems caused by water shortage in arid regions, and it has become a key issue in water resources planning. In the past several decades, many methods have been proposed to assess ecological flow for rivers and ecological water level for lakes or wetlands. To balance water uses by human and ecosystems, we proposed a general multi-objective programming model to determine minimum ecological flow or water level for inland water bodies, where two objectives are water index for human and habitat index for ecosystems, respectively. Using the weighted sum method for multi-objective optimization, minimum ecological flow or water level can be determined from the breakpoint in the water index–habitat index curve, which is similar to the slope method to determine minimum ecological flow from wetted perimeter–discharge curve. However, the general multi-objective programming model is superior to the slope method in its physical meaning and calculation method. This model provides a general analysis method for ecological water uses of different inland water bodies, and can be used to define minimum ecological flow or water level by choosing appropriate water and habitat indices. Several commonly used flow or water level assessment methods were found to be special cases of the general model, including the wetted perimeter method and the multi-objective physical habitat simulation method for ecological river flow, the inundated forest width method for regeneration flow of floodplain forest and the lake surface area method for ecological lake level. These methods were applied to determine minimum ecological flow or water level for two representative rivers and a lake in northern Xinjiang of China, including minimum ecological flow for the Ertix River, minimum regeneration flow for floodplain forest along the midstream of Kaxgar River, and minimum ecological lake level for the Ebinur Lake. The results illustrated the versatility of the general model, and can provide references for water resources planning and ecosystem protection for these rivers and lake. 相似文献
9.
During the period 2000–03, local potato cultivars in Estonia, Latvia, Lithuania, Poland and Denmark were tested for foliar resistance to Phytophthora infestans (late blight) in an international field trial network. Four standard cultivars were included in the trials: Sava, Oleva, Danva and Kuras. Primary disease-assessment data were entered into a common database, and parameters from the disease progress curves were calculated and made available on interactive web pages. A regression model, using relative area under disease progress curve (RAUDPC) values for cv. Oleva as a reference, was developed for the estimation of 1–9 scale values, where 1 = most susceptible. Standard deviations for the estimated 1–9 scale values and a nonparametric rank stability analysis of RAUDPC were used to evaluate the stability of resistance of the cultivars. Overall, the results showed stability of resistance for cvs Sava, Oleva and Danva, but not for Kuras. Use of the Internet-based Web-Blight service in this study facilitated comparison of results among countries for the level and stability of resistance. The estimated 1–9 scale values were similar to, or slightly lower than, those from official cultivar lists or from the European Cultivated Potato Database, especially for the more resistant cultivars. Possible reasons for discrepancies from different sources and locations are discussed. It is concluded that RAUPDC and the derived 1–9 scale values are useful for ranking cultivars for resistance to P. infestans , but this information is not detailed enough for use in a decision support system for late blight control. 相似文献
10.
M. Barbina Taccheo Claudio Spessotto Bruno Bresin Lucia Bagarolo 《Pest management science》1984,15(6):612-615
A method is described for the simultaneous determination of residues of five fungicides used for foliar treatment of apple and pear trees, and for postharvest application. After extraction, the mixture of these fungicides is cleaned-up on a ‘SEP PAK C18’ cartridge and the components determined by gas-liquid chromatography with electron-capture detection. The minimum detectable amounts in apples and pears, on a fresh weight basis, were 0.005mg kg−1 for vinclozolin, 0.010mg kg−1 for captan, folpet and iprodione, and 0.020 mg kg−1 for captafol. The percentage recovery for each fungicide (calculated by analysing four samples of untreated apples and pears, to which varying concentrations of each active ingredient had been added) varied for vinclozolin between 70.0 and 89.2, for captan between 72.0 and 83.8, for folpet between 73.0 and 93.0, for captafol between 70.8 and 91.8, and for iprodione between 75.1 and 97.1. 相似文献
11.
Fenuron, monuron, diuron, siduron, linuron and neburon were tested for their inhibition of soil urease activity in order to investigate relationships between fertilizers and herbicides. The inhibition of urea hydrolysis in the selected soils was 10–33% for fenuron, 10–39% for monuron, 10–35% for diuron, 8–38% for siduron, 9–36% for linuron and 12–30% for neburon. In the field greater effects might be expected since the fertilizer/herbicide ratio would be lower than the one considered here. Some agronomic aspects of the relationship between fertilizers and herbicides are discussed. 相似文献
12.
在过去的10年间,伴随着蛋白质组学定量质谱实验技术的发展,产生了大量相应的数据处理手段。本文阐述了定量质谱的主要实验手段及其原理,介绍了不同无标记质谱数据分析软件的特点及其用途,并列举已有的常用定量质谱数据分析软件类型。本综述对研究人员更好地寻找适合实验目的的计算机软件以及编写新型数据分析软件具有一定的参考价值。 相似文献
13.
14.
方形喷洒域变量施水精确灌溉喷头实现理论研究 总被引：7，自引：0，他引：7
在总结国内外变量施水精确灌溉喷头实现方法的基础上,对方形喷洒域变量施水精确灌溉喷头的实现条件进行了研究。通过理论分析,给出方形喷洒域变量施水精确灌溉喷头的射程、流量和转速应服从的变化规律和计算公式。指出这种喷头在组合喷洒时,为保证组合喷灌均匀性达到喷灌的技术要求,需要首先提高单喷头喷灌均匀系数。通过比较分析,得出了这种喷头的最优水量分布曲线应为类矩形的结论。研究结果为方形喷洒域变量施水精确灌溉喷头实现方法的研究提供了理论依据。 相似文献
15.
H. RØNde Kristensen 《EPPO Bulletin》1984,14(3):381-387
A programme of meristem-stem tip culture of potato was initiated in Denmark in 1977 to eradicate Corynebacterium sepedonicum and at the same time produce virus-free stocks. The procedures for obtaining the cultures, and ksting for viruses, at the National Institute of Plant Pathology are described. The first tuber generation is further propagated for 2 years by the Research Institute for Potatoes at Tylstrup. Selected growers then multiply the « meristem potatoes >> under the pre-basic system for another 3 years, under the supervision of the National Committee for Health Control of Seed Potatoes. 相似文献
16.
Following the entry into force of French Decree 2012‐140, published on 30 January 2012, concerning authorization of the entry to French territory and introduction into the environment of non‐indigenous macro‐organisms (beneficial, including pollinators and biological control agents) useful for crops, the French Agency for Food, Environmental and Occupational Health and Safety (ANSES) is in charge of the assessment of applications for authorization submitted by petitioners. This article presents some relevant definitions and briefly describes the process of evaluation and authorization of non‐indigenous macro‐organisms in France. It also summarizes the data requirements for application for import of non‐indigenous macro‐organisms for use under containment conditions or for introduction of non‐indigenous macro‐organisms into the environment. 相似文献
17.
Procedures are described for the analysis of crops for residues of tetrachlorvinphos (Gardona, trans-isomer of dimethyl 1-(2′,4′,5′-trichlorophenyl)-2-chloroyinyl phosphate) insecticide together with methods for the analysis for residues of its isomer and its conjugated and non-conjugated breakdown products. Suitable procedures for the extraction are described together with procedures for the cleanup of the extracts by partition or column chromatography and final analysis down to 0·01 ppm or less by gas-liquid chromatography with electron capture detection. 相似文献
18.
《EPPO Bulletin》1990,20(3):493-500
This guideline gives instructions for conducting trials on the efficacy evaluation of growth regulators used on seed potatoes for rapid desiccation of the haulms without damaging the tubers. Haulm destruction is essential for seed potato production and may also be used for other potatoes (although not generally for early potatoes). 相似文献
19.
实验表明引起松赤枯病的桔斑盘多毛孢菌(Pestalotiopsis funerea (Desm.) Stey)菌丝生长的适宜温度为19℃-25℃,最适温度斑22℃。在PDA、CDA加酵母粉及麦芽膏琼胶培养基上生长发育良好。孢子萌发最适温度为22℃,相对湿度低于85%时不萌发。孢子萌发率在自来水中为17%,在寄主表面为8%,在麦芽膏营养液内为73%。95%相对湿度条件下在寄主枝条上产孢数量最多。病菌在光照下方能产生子实体,3600Å波长的光线对产孢具有促进作用。病菌对水培及盆栽的寄主枝叶具侵染作用。多菌灵、代森锌锰、抑菌灵、Prochloraz和lprodione五种药剂均对菌丝生长有抑制作用,其抑菌中量及完全抑菌最低剂量分别为:多菌灵0.0352,0.1075ppm;Prochloraz 0.0071,0.1102ppm;lprodione 3.2917,110.1827ppm;代森锌锰37.5238,98.4069ppm;抑菌灵抑菌中量为11.6580ppm。药剂对孢子萌发的抑菌中量和完全抑菌最低剂量为抑菌灵0.7877,4.4791ppm;Prochloraz2.4434,10.0511ppm;代森锌锰20.1575,120.5289ppm。 相似文献
20.
根据番茄斑萎病毒属(Tospovirus)中6种病毒S RNA上的N基因序列设计特异性引物,建立可同时检测这6种Tospovirus病毒的多重PCR体系。多重PCR扩增结果显示,番茄环纹斑点病毒(776 bp)、甜瓜黄斑病毒(505 bp)、鸢尾黄斑病毒(296 bp)、凤仙花坏死斑病毒(221 bp)、番茄斑萎病毒(175 bp)和番茄褪绿斑病毒(110 bp)均出现清晰的目标条带,各病毒的特异性引物不会对其他病毒产生非特异性扩增。本研究建立的6种Tospovirus病毒的多重PCR检测方法,有助于提高目标病毒的检测效率。 相似文献