高温处理对烟草甲各虫态的致死作用研究     

吕建华  ;钟建军  ;张会娜  ;马丹  ;苏新宏  ;杜阅光 《商界．城乡致富》2014,(3):15-17

[目的]为有效实施烟草储藏害虫综合治理、确保烟草及其制品品质提供新方法。[方法]研究不同温度（25、35、45、55、60、65℃）下处理不同时间（60、75、90、105、120 s）对烟草甲成虫、蛹、幼虫和卵的致死作用。[结果]结果表明,不同处理温度、不同处理时间对烟草甲各虫态的致死作用效果差异显著。在处理温度为25、35和45℃时,该试验各个处理时间对烟草甲各虫态均无致死作用,而在处理温度为55℃以上时对烟草甲各虫态均具有较强的致死作用。在处理温度为60℃时,对烟草甲成虫、蛹、幼虫和卵达到100%致死作用的最短处理时间分别为90、120、75和75 s。[结论]高温处理可以作为一种有效的害虫防治方式运用到储烟害虫综合治理当中。  相似文献   

黑龙江西北地区马铃薯高产栽培技术     

许更宽 《中国农村小康科技》2010,(6):18-20

根据黑龙江西北地区的气候、土质、降雨规律等自然条件,从找准制约马铃薯产量的原因,运用科学的栽培技术,合理选地、选茬、整地,选择适合当地的栽培品种,适时早播,合理密植,科学施肥.加强田间管理,掌握病虫害防治方法等方面论述了黑龙江西北地区马铃薯高产栽培技术.  相似文献   

.NET平台下智能语音提示系统的开发     

赵新海  曹斌 《天津农学院学报》2010,17(4):54-56

利用Microsoft Speech SDK 5.1语音开发包提供的语音合成引擎,在.NET平台下开发了一个能够朗读中英文混排文本的智能语音提示系统,为人们合理安排工作和学习提供了帮助。系统页面友好,操作简单。  相似文献   

Arachidonic acid immunoregulation in lambs persistently infected with border disease virus     

M. M. Sawyer  L. L. Williams  A. C. Ode  n  S. N. Giri  B. I. Osburn 《Comparative immunology, microbiology and infectious diseases》1993,16(4):281-287

To evaluate arachidonic acid-related immunoregulatory mechanisms during long-term persistent pestivirus infection, we measured plasma contents of leukotriene C4 (LTC4), prostaglandin D2 (PGD2) and their plasma fatty acid (FA) precursor, arachidonic acid (AA), in six lambs with congenital border disease (BD). Significantly elevated average plasma LTC4 during the first half year of life was associated with increased PDG2 when compared to uninfected control lambs. Significantly elevated total plasma esterified AA stores suggest an effective BDV-mediated prostenoid immunostimulation. However, at 1 yr old, prostenoid secretion had fallen to normal (LTC4) or below normal (PGD2) levels. In contrast, there remained significantly elevated plasma esterified AA, present as available substrate for formation of these anti-viral immunoregulatory agents. These results suggested that preventing mobilization of AA from lipid stores for effective immune responses may be a viral strategy of BD virus that is associated with long term border disease effects.  相似文献   

Etude de la persistance d'une activite du virus grippal H₁N₁ (swine) dans les elevages porcins en dehors des phases epidemiquesStudy of the persistence of activity of the H₁N₁ influenza virus in swine intensive units out of epidemical phases     

F. Madec  J. M. Gourreau  C. Kaiser  J. Le Dantec  P. Vannier  M. Aymard 《Comparative immunology, microbiology and infectious diseases》1985,8(3-4)

Une étude est mise en place dans un groupe de 16 élevages intensifs venant de connaitre une attaque grippale et pratiquant à la fois le naissage et l'engraissement dans la région de Bretagne (France). L'objet de cette étude est de mettre en évidence une activité du virus grippal au sein des élevages en dehors des vagues épidémiques. Dans chaque élevage, 2 lots de porcelets sont individuellement suivis depuis la phase d'allaitement jusqu'à l'abattage. Des contrôles sérologiques mensuels sont pratiqués en vue de suivre l'évolution des anticorps grippaux ainsi que ceux de la maladie d'Aujeszky. En outre des écouvillonnages nasaux et des prélèvements de poumons sont réalisés en vue de recherches virales. Ces travaux sont accompagnés par la collecte de renseignements épidémiologiques dans chacun des élevages. Les anticorps grippaux d'origine colostrale inhibant l'hémagglutination décroissent assez rapidement chez le porcelet. Par la suite une conversion sérologique est observée sur près de 10% des animaux suivis. Les animaux concernés appartiennent à 4 des 16 élevages. La séroconversion intervient généralement après 3 mois d'âge. Aucun isolement viral n'a pu être réalisé. Certaines conditions semblent associées à la persistance d'une activité virale comme la démographie déséquilibrée du troupeau de truies, la conduite en continu de la porcherie d'engraissement, la préexistence d'une pathologie respiratoire sévère. Une séroconversion Aujeszky est également observée dans 3 des 4 élevages concernés par l'activité du virus grippal.  相似文献   

Incorporation of tracers and dazomet by rotary tillers and a spading machine     

J. Juzwik  D. L. Stenlund  R. R. Allmaras  S. M. Copeland  R. E. McRoberts 《Soil & Tillage Research》1997,41(3-4)

Soil fumigant efficacy in forest-tree and ornamental nurseries depends on the tillage tool used for incorporation. Maximum depth and uniformity of incorporation of surface applied materials by three rotary tillers and a spading machine were compared in a loamy sand nursery using ceramic-sphere tracers (1–3 mm diameter) and dazomet (tetrahydro-3,5,dimethyl-2H-1,3,5-thiadiazone-2-thione) micro-granules. Depth of incorporation in the top 30 cm of soil was evaluated by (1) recovery of incorporated spheres in 2 cm increments, (2) biocidal activity in 6 cm increments, and (3) cone resistance by 1.5 cm increments to 45 cm. Uniformity of incorporation was evaluated by sphere recovery and biocidal activity. Depths above which more than 95% of the spheres were recovered for the four implements were: 12.5 cm, Kuhn and Fobro rotary tillers; 17 cm, Northwest rotary tiller; 21 cm, Gramegna spading machine. The spading machine produced a distribution of spheres through the soil profile closest to a uniform distribution compared with that produced by the three rotary tillers. Lettuce seed (Lactuca sativa L.) germination was inhibited in the upper 12 cm in low and high dazomet rate treatments, indicating that all four implements effectively incorporated dazomet into that zone. Maximum depth (24 cm) for total inhibition of germination was observed for the spading machine regardless of chemical rate. Cone index values showed the following maximum penetration: 14 cm, Fobro rotary tiller; 22 cm, Kuhn and Northwest rotary tillers; 27 cm, spading machine. All three measures of depth show a distinct superiority of the spading machine when the chemical fumigant must reach depths greater than 18 cm. Within transects across the width of the implement, variations of sphere counts among 5 cm³ volumes were much larger for the rotary tillers than for the spade machine.  相似文献   

Identifying, understanding, and describing spatial processes in agricultural landscapes — four case studies     

Ole Wendroth  Peter Jürschik  K. Christian Kersebaum  Hannes Reuter  Chris van Kessel  Donald R. Nielsen 《Soil & Tillage Research》2001,58(3-4):113-127

To evaluate the quality of the ecosystem and for making resources and land management decisions landscapes have to be assessed quantitatively. For a better understanding of landscape processes and their characterization, the analysis of the inherent variability is a major factor. Four case studies in which problems associated with landscape analysis are discussed. Spatial processes remain a main focus, as their analysis provides information on the relation between relevant state variables in agricultural landscapes. Variogram analysis showed that mineral soil nitrogen (N_min) sampled in a field at different scales, domains, and times is an instationary spatial process. Spatial association of grain yield, soil index and remotely sensed vegetation index may not be identifiable from kriged contour maps as local coincidence may be obscured behind classified areas. Crop yield in subsequent years and remotely sensed information are not related if a unique response is assumed. An alternative data stratification procedure is described here for the identification of different response functions in agricultural ecosystems. Processes of crop yield and underlying variables are described in autoregressive state-space models. This technique incorporates both deterministic and stochastic relations between different variables and is based on relative changes in space.  相似文献   

The use of a water budget model and yield maps to characterize water availability in a landscape     

Dennis Timlin  Yakov Pachepsky  Charles Walthall  Sara Loechel 《Soil & Tillage Research》2001,58(3-4):219-231

Crop yield maps may contain substantial corollary information regarding the distribution of yield related soil properties across a landscape. One of these properties is water holding capacity (WHC). Since WHC is an important parameter for crop models and is also critical for crop yield, our objective was to determine if WHC could be estimated by matching simulated yield with yield map data. We collected soil cores for water retention measurements and recorded plant phenological stages from 60 plots on four transects over two growing seasons (1997 and 1998). Soil cores were also sampled on 40 other locations set out on a grid pattern. We utilized a simple water budget model that uses the relative transpiration ratio to calculate relative yield from available water in the soil profile. Rainfall, potential evapotranspiration and soil water holding capacity are input. An optimization program varies the WHC to produce a grain yield similar to the one from the yield map at a particular location. This analysis was carried out over several scales by averaging yields over 55 m×71 m, 27 m×35 m, and 11 m×14 m areas. Yield data from 2 years were used. Yields from the transects in both years were significantly related to measured WHC in the surface 0–10 cm of soil. The calculated stress indices from the water budget model and estimated available WHC calculated for the 1997 data were similar to those calculated for the 1998 data where data were aggregated in 27 by 35 m or larger blocks. The contour map of estimated WHC was similar to the map of measured WHC for some features though there were also some differences. Use of multiple years of yield data are required to give stable results for estimated water holding capacities.. This information could be used in a farm management plan by allowing a producer to classify a field into areas that are buffered against drought and areas more susceptible to drought.  相似文献   

Wind erosion and airborne dust deposition in farmland during spring in the Horqin Sandy Land of eastern Inner Mongolia, China   总被引：9，自引：0，他引：9  

Feng-Rui Li  Li-Ya Zhao  Hua Zhang  Tong-Hui Zhang  Yasuhito Shirato 《Soil & Tillage Research》2004,75(2):121-130

In the Horqin Sandy Land of eastern Inner Mongolia in northern China, wind erosion in farmland is very common in a period from thawing of frozen surface soil in mid-March to sowing of crops in the end of April, largely because of dry and windy weather. However, little is known about the magnitude of wind erosion and associated nutrient losses due to erosion and the addition of nutrients by airborne dust deposition to farmlands during this period. A field experiment was conducted in an Entisol with sand origin under corn (Zea mays L.) production to investigate daily changes in wind speed and wind erosion intensity (as measured by soil transport rate) over a period from 20 March to 30 April 2001. We also measured daily rates of airborne dust deposition during the spring seasons with the high frequency of dust storm occurrence. The rates of soil transport by wind varied greatly from 13.2 to 1254.1 kg ha⁻¹ per day, averaging 232.1 kg ha⁻¹ per day, largely attributable to great variation between days in wind speed within the study period. The potential losses of nutrients through wind erosion were 0.26–24.95 kg ha⁻¹ per day (averaging 4.62 kg ha⁻¹ per day) in organic matter, 0.02–1.64 kg ha⁻¹ per day (averaging 0.31 kg ha⁻¹ per day) in nitrogen and 0.01–0.7 kg ha⁻¹ per day (averaging 0.13 kg ha⁻¹ per day) in phosphorus. The mean rates of airborne dust deposition ranged from 4.0 to 48.9 kg ha⁻¹ per day, averaging 19.9 kg ha⁻¹ per day, during the spring seasons. The potential addition of organic matter, nitrogen and phosphorus by dust input to the experimental field was, on average, 0.54, 0.04 and 0.02 kg ha⁻¹ per day, respectively. Although the addition was a fraction of the losses due to erosion, nevertheless, dust input in the spring seasons is one of the major suppliers of soil nutrition. The fact that the addition of nutrients by dust is about 1/10 of the losses of soil nutrients through wind erosion suggests that developing and adopting more effective management practices to reduce soil erosion losses and to improve soil fertility are crucial to achieve a sustainable agricultural system in a fragile, semiarid sandy land environment.  相似文献   

Effect of aggregate size and soil water content on emergence of soybean (Glycine max, L. Merr.) and maize (Zea mays, L.)     

M. V. Braunack 《Soil & Tillage Research》1995,33(3-4):149-161

Rapid wetting of irrigated soils often leads to slaking and slumping, and on drying a surface crust and hard-set conditions may occur. This results in reduced crop emergence unless the surface is kept moist. The effect of aggregate size and water content on the emergence of soybean and maize from an Entic chromustert (heavy cracking clay) was determined using pots of sieved aggregates with size ranges less than 1, 1–2, 2–5 and 5–15 mm at soil water contents of 15, 20 and 25 g (100 g)⁻¹. Unsieved soil was used as a control. Greatest emergence tended to occur from fine (1–2 mm) seedbeds compared with coarse (5–15 mm) seedbeds for both crops. A covered treatment, simulating a stubble mulch, resulted in greater emergence than an uncovered treatment for all water contents and aggregate sizes. Earlier emergence occurred from finer (less than 1 mm and 1–2 mm) seedbeds than from coarse (5–15 mm) seedbeds, and at the greatest water content used. Soil strength, measured with a shear vane, decreased with increasing water content and tended to be less on fine (1–2 mm) seedbeds compared with very fine (less than 1 mm) or coarse (5–15 mm) seedbeds. It is recommended that, for good emergence from this Entic chromustert, seedbeds be brought to a water content of 25 g (100 g)⁻¹ by capillary wetting to prevent hardsetting and consist of 1–2 or 2–5 mm aggregates for soybean and maize, respectively, and have a stubble mulch on the surface. This corresponds to an equivalent depth of water of 15 mm and 9 mm for soybean and maize, respectively, in the top 50 mm of the profile.  相似文献