首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Z. CHLADEK 《EPPO Bulletin》1983,13(3):419-424
Results are reported on the prevention of losses of pesticide liquids due to droplet drift during aerial spraying. The effect of two basic factors was tested: a) change in drop size achieved either by use of different nozzles or by their modification or by regulation of the physical properties of the pesticide liquids; b) change of external conditions of drop fall achieved by the regulation of flight altitude, arrangement of nozzles on the aircraft, accuracy of operation of the spraying equipment The experiments proved that droplet size was most affected by use of TeeJet nozzles with Sabatka terminals, and to a lesser extent by the Lo-Drift agent Both factors limited the formation of the smallest drops, up to 100 μm especially. Accurate operation and maintenance of the spraying equipment (especially timely turning off at the end of lanes) has a great effect on limiting drift Optimum flight altitude (according to wind speed) is a compromise between the effort to limit drift and droplet evaporation and the achievement of required uniformity of deposition (CV). With the Z-37 aircraft, the optimum flight altitude in good weather conditions is about 4-5 m. Earlier experiments (to 1978) indicated good results with the addition of Ulvapron agent (21/ha) and Trition CS 7 (0.3%) mainly in warm (above 20°C) and dry (below 60 % R.H.) weather.  相似文献   

2.
风洞环境下喷头及助剂对植保无人飞机喷雾飘移性的影响   总被引：2，自引：0，他引：2  
为探究和减少植保无人飞机喷雾施药过程中的雾滴飘移,采用由单个旋翼与喷头组成的喷雾单元,在可控风洞环境条件下进行了模拟飞行喷雾试验,控制风洞条件为风速5 m/s、喷雾压力0.3 MPa及旋翼转速2300 r/min不变,对比研究了11种喷头、4种代表性助剂以及不同温度/相对湿度条件对雾滴飘移的影响,采用飘移潜在指数(DIX)及相对减飘率(DPRP)两项指标进行对比评估。结果表明:在温度/相对湿度为20℃/RH 80%条件下,不同类型喷头喷雾药液在空中垂直面和水平距离上的飘移沉积量分布均呈现显著的规律性变化趋势,与对照喷头F110-03相比,喷头飘移潜在性从大到小依次为:TR80-0067>ST110-0067>XR110-01>ST110-015>TR80-01>ST110-02>XR110-03>对照F110-03>IDK系列,其中IDK120-01与IDK120-015喷头的减飘移效果相近并为最好;在30℃/RH 40%条件下,采用XR110-01喷头,分别添加助剂0.5%Silwet DRS-60、1.0%"迈飞"(MF)和1.0%Y-20079后,与不添加助剂的对照相比,平均减飘率分别为43.3%、15.6%和5.2%,表明不同助剂对飘移的影响不同,需考虑助剂类型及其减飘效果合理选用;在20℃/RH 40%、20℃/RH 80%、30℃/RH 40%和30℃/RH 60%条件下,XR110-01喷头与添加1.0%MF助剂组合有利于空中飘移的减少,尤其是高温/低湿条件下,添加助剂的减飘移效果较好。该研究结果可为植保无人飞机的喷头选择、喷雾助剂筛选和实际应用提供参考和指导,并为进一步研究喷头及助剂的减飘技术提供数据基础。  相似文献   

3.
Cereal crops were sprayed with conventional hydraulic nozzles (2501/ha), electrostatic hydraulic nozzles (66 l/ha), spinning discs (aqueous 5 l/ha and oil 2 l/ha) and ICI « Electrodyn >> nozzles (1 and 2 l/ha). The ULV sprays were applied with or without air assistance. An experimental triazole fungicide was applied with fluorescent tracer and control of RhynchospoHum secalis in barley and Erysiphe graminis in wheat was compared with deposit data. The two high volume spray systems performed well with no significant differences in disease control or deposition between charged and uncharged modes at 66 l/ha. The spinning disc and « Electrodyn >> systems performed well with air assistance but, without air, deposition was uneven and disease control inferior. The «Electrodyn>> system often produced the largest total deposits but, without air, assistance spray deposition was concentrated mainly in the upper plant parts. The results indicate that under suitable conditions application volumes as low as 1 l/ha can be as effective biologically as high volumes when the same amount of fungicide per hectare is used. Relationships between spray distribution within cereals and sites for pest and disease attack are discussed with regard to different methods of application.  相似文献   

4.

Background

Pesticide spray drift, which is the movement of pesticide by wind to any location other than the intended area, is hazardous to human, animal, food safety and environmental health. It is not possible to completely eliminate spray drift during spraying with field crop sprayers, but spray drift can be reduced by developing new technologies. The most common methods to reduce spray drift are carrying the droplets to the target with air-assisted spraying, electrostatic spraying, preferring air induction nozzles and boom shields. With these methods, it is not possible to make a change on the sprayer depending on the wind intensity during spraying. In this study, a novel servo-controlled spraying system was designed and developed to change the nozzle orientation angle in the reverse direction of the wind current to reduce the ground spray drift in real time and automatically in a wind tunnel. The displacement in the spray pattern (Dc) was used as a ground drift indicator for each nozzle to evaluate the spray drift.

Results

The developed system, operated by LabVIEW software, calculated different nozzle orientation angles depending on nozzle types, wind velocities and spraying pressures. Orientation angles calculated for different test conditions achieved in reduction were up to 49.01% for XR11002 nozzle, 32.82% for AIXR11002 nozzle and 32.31% for TTJ6011002 nozzle at 400 kPa spray pressure and 2.5 m s−1 wind velocity.

Conclusion

The developed system, which has a self-decision mechanism, calculated the nozzle orientation angle instantaneously according to the wind velocity. It has been observed that the adjustable spraying nozzle system, sprayed with high precision towards the wind in the wind tunnel, and the developed system have advantages compared to conventional spraying systems. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

5.
喷杆喷雾机具有作业效率高、雾滴覆盖率高、沉积分布均匀、防治效果好等优点,是目前大田作物最主要的施药机具.但受作物冠层遮挡和侧风等气象条件的影响,导致喷杆喷雾机作业时雾滴难以穿透到植株中下部并伴随飘失.为改善喷杆喷雾机喷雾雾滴在作物冠层的穿透性并降低飘移量,本文优化设计了一种适用于大田作物的喷杆喷雾机冠层推拨装置.并分别...  相似文献   

6.
Low volume carbendazim sprays (25–100 litre/ha) applied with a knapsack mistblower fitted with twin nozzles or a mesh diffuser were compared with high volume sprays (760 litre/ha) from three pairs of ‘Spraying Systems’ Y6 nozzles on the vertical boom of a knapsack pressure sprayer. The carbendazim concentration and total amount deposited were measured by thin-layer chromatography and bioassay. The twin nozzles, which directed two spray streams 50° apart, deposited most fungicide on the plants using 100 litre/ha, and in two experiments 76 and 80% of theoretical amounts applied per plant were detected in or on the leaves. At 25 litre/ha, the distribution was less uniform and the deposit efficiency was 74%. The mesh diffuser at 100 litre/ha was less efficient; where the spray was directed between and parallel to the rows of tobacco the deposits were 26 and 42% of the total carbendazim applied, whereas directing the spray at an angle of about 45° towards the rows of tobacco increased the deposit to 57%. Sprays applied at a pressure of 410 kPa (4.1 bar) from Y6 nozzles deposited only 16% of the active ingredient onto the leaves. Better control of powdery mildew caused by Erysiphe cichoracearum was obtained with dinocap using the mesh diffuser than with either the Y6 nozzles or with dusts from a motorised duster.  相似文献   

7.
R. MERRETT 《EPPO Bulletin》1983,13(3):413-417
Chemical desiccation with Regione (diquat) of oilseed crops prior to harvesting is now a well established farming practice. The many varied practical (and economic) advantages give the farmer more flexibility and control in planning his operations at a particularly busy time of year. However, desiccants are not selective of green plant tissue, so it is important that the spray is confined to the target crop. Spray drift is not normally a problem with ground spraying, but with aerial application particular care in the selection of equipment, flying technique, and climatic conditions is essential. This is particularly important when desiccating early maturing crops, such as oil-seed rape, when other crops, for example sugar beet and maize, are still green and growing. The potential spray drift risk can be reduced by planting similar crops in large blocks rather than in fragmented strips throughout the farm. By restricting the length of spray boom on the aircraft, using efficient diaphragm shut-off nozzles angled rearwards to the airstream, fitted with nozzles such as spraying Systems D8 or 10 with 46 or 56 swirl plates operating at maximum pressure of 2 bar, much of the drift hazard resulting from the equipment can be reduced. It is essential that the spray is turned on/off only in level flight and that the height of the spray boom above the top of the crop is less than 2.5 m. Spraying should only be carried out in wind speeds of 1-4 m/s and never under temperature inversion conditions. Large helicopters should only be used discriminately in very large areas of crop.  相似文献   

8.
BACKGROUND: Increasingly, Flemish greenhouse growers are using spray booms instead of spray guns to apply plant protection products. Although the advantages of spray booms are well known, growers still have many questions concerning nozzle choice and settings. Spray deposition using a vertical spray boom in tomatoes and strawberries was compared with reference spray equipment. Five different settings of nozzle type, size and pressure were tested with the spray boom. RESULTS: In general, the standard vertical spray boom performed better than the reference spray equipment in strawberries (spray gun) and in tomatoes (air‐assisted sprayer). Nozzle type and settings significantly affected spray deposition and crop penetration. Highest overall deposits in strawberries were achieved using air‐inclusion or extended‐range nozzles. In tomatoes, the extended‐range nozzles and the twin air‐inclusion nozzles performed best. Using smaller‐size extended‐range nozzles above the recommended pressure range resulted in lower deposits, especially inside the crop canopy. CONCLUSIONS: The use of a vertical spray boom is a promising technique for applying plant protection products in a safe and efficient way in tomatoes and strawberries, and nozzle choice and setting should be carefully considered. Copyright © 2009 Society of Chemical Industry  相似文献   

9.
Fifteen field experiments were conducted from 2002 to 2005 to determine the influence of the nozzle type, spray volume, spray pressure, and herbicide rate on herbicidal efficacy in soybean. There was no effect of the nozzle type on herbicidal efficacy with fomesafen, bentazon, glyphosate, and cloransulam‐methyl when applied at the manufacturer's recommended rate. The control of Echinochloa crus‐galli (barnyardgrass) with quizalofop‐p‐ethyl was improved when applied with flat fan (FF) nozzles compared with air induction (AI) nozzles. There was an increase in weed control with the FF nozzles compared with the AI nozzles in four of the 13 comparisons when the herbicides were applied at half the recommended rate, while in two situations, application with the AI nozzles resulted in improved weed control. With the FF nozzles, there was no effect of the water carrier volume on weed control with bentazon, glyphosate, and cloransulam‐methyl. The control of Abutilon theophrasti (velvetleaf) and Chenopodium album (common lambsquarters) with fomesafen and E. crus‐galli with quizalofop‐p‐ethyl was improved at the higher water carrier volume. With the AI nozzles, the control of A. theophrasti and Ambrosia artemisiifolia (common ragweed) with fomesafen and E. crus‐galli with quizalofop‐p‐ethyl was improved at the higher water carrier volume, while the control of A. theophrasti and Polygonum persicaria (ladysthumb) was improved with glyphosate at the lower water carrier volume. With the AI nozzles, the control of C. album with bentazon and E. crus‐galli with quizalofop‐p‐ethyl was improved at the higher spray pressure. There was no effect of the nozzle type on the soybean yield with glyphosate, cloransulam‐methyl, and quizalofop‐p‐ethyl. The use of the FF nozzles compared with the AI nozzles to apply fomesafen and bentazon increased the soybean yield by 6 and 7%, respectively. Based on this study, the optimum nozzle type, water carrier volume, and spray pressure is herbicide‐ and weed species‐specific.  相似文献   

10.
Investigations of the effects of varying the boom height, working pressure, and wind speed on spray drift from a field sprayer are reported. By increasing the boom height from 40 to 80 cm drift increased from 1% to 3–2%; by increasing the pressure from 2–5 bar to 10 bar drift increased from 1–4% to 2–9%, and by increasing the wind velocity from approximately 1–5 m/s to approximately 4–0 m/s drift increased from 1–4% to 2–9%. A significant negative correlation was found between drift and the logarithm of the distance from the nozzle. A significant positive correlation was found between drift damage on barley plants and the logarithm of the spray-liquid deposit. Under ideal conditions, and with correctly adjusted spray equipment, total spray drift was 14% of applied spray. Under unfavourable conditions, and with wrong adjustments of the sprayer (boom height and pressure) drift was 37% of the applied spray. It is concluded that field spraying should not be carried out in wind speeds of more than 3 m/s. The boom should be approximately 40 cm high, and the working pressure should not exceed 2–5 bar for herbicide spraying. Effet de la hauteur de la rampe, de la pression de travail et de ia Vitesse du vent sur les entraînements de pulvérisqtion par embruns Les auteurs rapportent les résultats de recherches sur les effets de la variation de hauteur de ta rampe, de la pression de travail et de la vitesse du vent sur I'entraînement des embruns provenant d'un pulvérisateur à grand travail. L'élévation de ia rampe de 40 à 80 cm a accru I'entraînement de 1 à 3,2%; I'augmentation de la pression, de 2.5 à 10 bars a accru I'entraînement de 1,4 h 2,9% et I'augmentation de la Vitesse du vent de 1,5 à 4,0 màtres/sec a accru I'entraînement de 1,4 à 2,9%. Une corrélation négative significative a été trouvée entre Tentraînement et le logarithme de la distance à partir de la buse. Une corrélation positive significative a été trouvée entre I'entraînement et le logarithme du dépét de la bouillie pulvérisée. Dans les conditions optimales et avec un pulvérisateur correctement réglé, I'entraînement total a été de 1,4% du traitement appliqué. Dans des conditions défavorables et avec des régiages défectueux du pulvérisateur. (hauteur de la rampe et pression) I'entraînement a atteint 37%. En conclusion, les traitements au champ par pulvérisation ne doivent pas être effectuées si la vitesse du vent dépasse 3 m/sec. La rampe doit être à 40 cm du sol environ et la pression de travail ne doit pas excéder 2,5 bars pour une pulvérisation effectuée avec un herbicide. Der EirtJJiiss ion Spritzbalkcnhohe, Betriebsdriick und Wind-geschwindigkeit aufdie Abtrift. Eswird über den Einfluss unterschiedlicher Spritzbalkenhöhen, Betriebsdruck und Windgeschwindlgkeit aufdie Abtrift beien einem Feldspritzgerät berichtet. Bei Erhöhung des Spritzbalkens von 40 auf 80 cm stieg die Abtrift von I auf 3,2%; eine Steigerungdes Druckes von 2,5 auf 10 bar erhöhte die Abtrift von 1,4 auf 2,9% und durch eine Erhöhung der Windgeschwindigkeit von etwa 1,5 m/s auf etwa 4 m/s, steigerte sich die Abtrift von 1,4 auf 2,9%. Zwischen der Abtrift und dem Logarithmus des Abstandes von der Düse, wurde eine gesichertc negative Korrelation gefunden. Eine gesicherte positive Korrelation ergab sich zwiscben Abtrift Beschädigung von Gerste und dem Log-arithmus des Spritzbelages. Bei idealen Dedingungen und richtig eingestelltem Spritzgerät, betrug die gesamie Abtrift 1,4% der ausgebrachten Bruhe. Unter ungüstigen Bedingungen und fiihcher Einstell-ung (Spritzbalkenhöhe und Druck), betrug die Abtrift 37%. Aus den Ergcbnissen wird geschlossen. dass man bei Windgeschwindigkeiten von mehr als 3 m/s nicht spritzen sollte. Der Spritzbalken sollte etwa 40 cm hoch sein und der Betriebsdruck sollte bei Herbizidspritzungen 2,5 bar nicht überschreiten.  相似文献   

11.
F. HARGITAI 《EPPO Bulletin》1983,13(3):345-349
In Hungarian agriculture, large-scale farming is characteristic. The average size of State Farms exceeds 7000 ha, while that of the agricultural cooperatives approaches 4000 ha. In general, farms are well mechanized and agrochemical usage is also high. Per hectare of arable land in Hungary, the amount of pesticides applied annually is about 5 kg active ingredient. The application is carried out by 7000 large-scale ground equipments, 4000 machines for orchard and vineyard treatments, and 115 brigades for aerial application. The selection of both appropriate equipment and mode of application has an important role in achieving adequate biological efficacy at reasonable cost while ensuring energy saving and protection of the environment Now and in the future, great importance must be given to the following:a) widespread use of up-to-date equipment for pesticide application; b) nozzle selection in accordance with the purpose to be achieved; c) avoiding or impeding the total depreciation of machinery; d) regular control of the correct adjustment and the general state of equipment and establishment of an adequate servicing system; e) selection of equipment adapted to the pesticide formulation concerned; f) increased use of specific pesticide formulations; g) increased use of additives in order to control surface tension, droplet formation, drift etc.; h) establishment of a balance between use of ground and aerial equipment under given farm conditions; i) improvement of economical aerial application in plant protection; j) development of test methods and equipments to control the standards of application; k) examination of combinations of pesticides and other chemical (e.g. fertilizers).  相似文献   

12.
以亿丰丸山3WP-500CN型号自走式喷杆喷雾机为研究对象,以诱惑红85作为指示剂,测定了6种喷雾助剂 (红太阳、倍力、迈丝、融透、印楝油和哈速腾)、3种喷头 (TEEJET-VP80015、ASJ-VP110015和LICHENG-VP11003) 以及3种喷雾压力 (0.2、0.4 和0.6 MPa) 对农药沉积利用率、药液雾化性能 (D50值雾滴密度等)、雾滴分布均匀性等喷雾参数的影响,以及240 g/L噻呋酰胺悬浮剂对水稻纹枯病防治效果及水稻产量的影响。结果表明:采用TEEJET-VP80015喷头,在0.4 MPa喷雾压力条件下,助剂哈速腾雾滴分布均匀性显著高于其他助剂,变异系数为0.11,同时对雾滴估计沉积量 (45.74 μL/cm2) 与分布跨度 (1.29) 的影响显著高于其他助剂;助剂迈丝对雾滴密度 (103.78个/cm2) 和农药沉积利用率 (83.88%) 的影响均显著高于其他助剂。采用TEEJET-VP80015喷头,在未添加助剂条件下,不同喷雾压力对雾滴分布跨度、雾滴附着率和农药沉积利用率影响差异显著,其中在0.6 MPa压力下,分布跨度为1.18,雾滴附着率为33.32%,农药沉积利用率为78.19%。在未添加助剂、0.4 MPa喷雾压力条件下,喷头LICHENG-VP11003对雾滴分布均匀性的影响显著高于另外两种喷头,变异系数为0.12,同时对雾滴覆盖率 (69.37%)、雾滴估计沉积量 (42.77 μL/cm2) 和农药沉积利用率 (75.79%) 的影响也显著高于另外两种喷头。各测定条件下,240 g/L噻呋酰胺悬浮剂对水稻纹枯病的防治效果与雾化性能和雾化参数结果一致,其中添加助剂迈丝后防治效果达到89.27%,显著高于添加其他助剂,增大喷雾压力到0.6 MPa,防治效果达到88.67%,显著高于其他压力条件;采用TEEJET-VP80015喷头,在0.4 MPa喷雾压力下,水稻产量为8301 kg/hm2,显著高于人工喷雾。因此,助剂与喷头类型均对自走式喷杆喷雾机施药时的农药沉积利用率、雾滴分布均匀性以及雾滴参数和雾化效果有显著的影响,在适当的喷雾压力下添加助剂可提高农药的防治效果。  相似文献   

13.
Abstract

Micron Sprayers Ltd have produced a sprayer, the Herbi, designed to produce uniform atomisation with both oil- and water-based formulations. Three different nozzle sizes give low, medium and high flow rates. In performance tests wetting agents were found to be necessary to produce uniform droplets. The volume distribution across the swath showed four peaks and for the flow rate, liquid and atomiser height examined the two major peaks were at 50 and 60 cms either side of the line of the sprayer, indicating a peak to peak width of 110 cm. Of the collected spray, 75% settled within a central band of 120 cm, 99% within 180 cm and 100% within 195 cm. To prevent superimposition of peaks leading to high overdose, a swath width of 150–160 cm is suggested, such that overlap occurs at the outer position of half peak height. To avoid excessive spray drift it is recommended that the sprayer is not used in any but very light wind. The authors conclude that this machine should prove very useful for very low volume application between rows in bush and tree crops, and for treating larger areas.  相似文献   

14.
Twelve field experiments were conducted over a 4 year (2002–2005) period to determine the influence of the herbicide dose, nozzle type, spray volume, and spray pressure on herbicide efficacy in field corn ( Zea mays L.). The control of Abutilon theophrasti (velvetleaf ), Ambrosia artemisiifolia (common ragweed), Chenopodium album (common lambsquarters), Amaranthus powellii (green pigweed), and Echinochloa crus-galli (barnyard grass) was improved with the use of full herbicide doses compared to half doses of bromoxynil, glufosinate, dicamba, and nicosulfuron. The yield was increased for bromoxynil, glufosinate, and nicosulfuron when the full herbicide dose was used. When applied at the manufacturer's recommended dose, flat fan nozzles, compared to air induction (AI) nozzles, provided better control of A. theophrasti , A. artemisiifolia , and C. album with bromoxynil, A. artemisiifolia and C. album with dicamba, and E. crus-galli with nicosulfuron. Bromoxynil, in relation to weed control, was the only herbicide that was affected by the water carrier volume. By increasing the spray pressure with an AI nozzle, there was an improvement in the control of A. theophrasti , A. artemisiifolia, and C. album with the application of bromoxynil and E. crus-galli with the application of nicosulfuron, with a yield increase with bromoxynil. Overall, this study concludes that the optimum nozzle type, water carrier volume, and spray pressure is herbicide- and weed species-specific.  相似文献   

15.
The biological effectiveness of deposits of binapacryl applied by a single high pressure nozzle was compared with similar deposits applied by twin low-pressure nozzles. Equal foliar deposit densities were obtained from the two systems but the single nozzles gave marginally better control of apple powdery mildew and fruittree red spider mite.  相似文献   

16.
A machine is described for experimental application of herbicides in volumes of spray liquid in the range 5–20 I/ha and at a uniform drop size. Uniformity of distribution is comparable to that from a conventional small-plot sprayer working under optimal conditions. The machine was used to apply 2,4-D ester, barban and tri-allate. Subsequent biological assessments revealed no major loss of effectiveness in weed control when compared with applications in 165 or 200 I/ha sprayed through hydraulic fan nozzles as in contemporary field practice. Essais préliminaires au champ avec l'ester du 2,4-D, le barbane et le triallate appliqués en pulvérisation avec un volume de 5 à 20 l/ha Un appareil est décrit pour l'application expérimental d'herbicides en pulvérisation avec un volume de liquide alla de 5 à 20 I/ha et une taille uniforme de gouttes. L'uniformité de la distribution est comparable à celle d'un pulvérisateur pour petites parcelles travaillant dans des conditions optimales. L'appareil a été utilisé pour appliquer du 2.4-D ester, du barbane et du triallate. Des essais biologiques effectués & la suite des traitements ont montré qu'il n'y avait pas de perte importante d'efficacité herbicide par comparaison avec des traitements appliqués avec 165 ou 200 1/ha en utilisant les buses S fente en usage dans la pratique actuelle des traitements au champ. Vorläufige Feldversuche mit 2,4-D Ester, Barban und Triallat mit Brühemengen von 5–20 l/ha Es wird ein GerSt beschrieben mit dem versuchsmässig Herbizide mit Brühemengen zwischen 5 und 20 1/ha bei gleichbleibender Tropfengrösse ausgebracht werden können. Die Gleichmässigkeit der Verteilung lässt sich mit der eines unter optimalen Bedingungen arbeitenden Parzellenspritz-geräts vergleichen. Mit diesem Gerät wurden 2,4-D Ester, Barban und Triallat ausgebracht. Die darauffotgende bio-logische Früfung zeigte keinen wesentlichen Verlust in der Wirksamkeit der Unkrautbekämpfung, verglichen mit den gegenwärtig üblichen Verfahren mit 163 oder 200 l/ha und Flachstrahldüsen.  相似文献   

17.
Abstract

The abrasive action of a copper fungicide on four nozzles commonly used in Nigeria when spraying cocoa for black pod control was evaluated. The spray solution flocculated and the nozzles frequently blocked indicating the need for an efficient filter. The single hollow cone type nozzle and the variable spray nozzle were the most highly abraded.  相似文献   

18.
Summary. Electron-capture gas chromatography was used to detect dicamba residues in three prairie soils, and the breakdown under different moisture conditions was studied. At rates equivalent to 1·1 kg/ha degradation was rapid in all soils at 25°C and at moisture levels in excess of the wilting point, with over 50% of the applied dicamba being dissipated in 2 weeks. Negligible breakdown occurred in the sterile soils, over a 4–week period, indicating that microbial decomposition could be an important factor contributing to dicamba degradation.
The persistence of dicamba was investigated under field conditions at three locations using small plots. Applications equivalent to 1·1 kg/ha were made in October 1971 for analysis in May 1972, and in May 1972 for analysis in August 1972. At both sampling dates no dicamha residues were detected in any of the treatments at the 0–5, 5–10 or 10–15 cm soil levels.
Degradation du dicamba dans les sots de prairies  相似文献   

19.
Conidia of the fungus Metarhizium flavoviride were formulated in a paraffinic oil, ‘Shellsol’ T, and sprayed using the Francome MkII exhaust nozzle sprayer. Germination of the conidia collected from the spray was reduced by 30% as compared to unsprayed conidia. However, in bioassays, there was no detectable difference in virulence with conidia collected from the spray samples and unsprayed formulation. This indicated that, despite the recorded reduction in the concentration of active conidia, the efficacy of the formulation remained unchanged after passing through the exhaust nozzle sprayer. The droplet size spectra produced by the sprayer were investigated using the Malvern series 2600cc particle size analyser. The optimum droplets for locust control produced by this sprayer were generated by the number 1 nozzle (internal diameter 2·5 mm) with the number 1 restrictor ring (internal diameter 12.5 mm) sprayed at a pressure of 0·2 bar. The droplets thus produced had a volume median diameter of 58 μm when the nozzle protruded between 1 and 2 mm above the level of the restrictor ring. Of the droplets in the spray plume created by these conditions, 33% were between 50 and 100 μm, a range recommended as an achievable optimum for the ultra-low-volume application of Metarhizium flavoviride. The role of the exhaust nozzle sprayer as a tool for the application of M. flavoviride for locust control is discussed with reference to other vehicle-mounted ultra-low-volume sprayers. © 1997 SCI  相似文献   

20.
Summary. The 'Vibrajet' nozzle is designed to produce relatively large droplets with 'low drift' characteristics. This system was evaluated for the overall application of paraquat, diquat and morfamquat in a number of agricultural situations in comparison with a fan jet. The biological efficiency achieved with the 'Vibrajet' nozzle was of the same order as that of the fan jet at the rates of application of the herbicides currently recommended in the United Kingdom. Five variables which affect the field performance of a spray system were investigated: volume of spray applied, concentration of wetter in the spray, rate of chemical applied, spray pressure and size of orifice. Changes in these factors made little improvement to the biological efficiency of the 'Vibrajet' nozzle.
Comparaisnn de la buse 'Vibrajet' et d'une bitse pinccau pom Vapplication generalisee des herbicides bipyridiliques  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号