张慧春,郑加强,周宏平,DORR G J.农药喷施过程中雾滴沉积分布与脱靶飘移研究[J].农业机械学报,2017,48(8):114-122.
ZHANG Huichun,ZHENG Jiaqiang,ZHOU Hongping,DORR G J.Droplet Deposition Distribution and Off-target Drift during Pesticide Spraying Operation[J].Transactions of the Chinese Society for Agricultural Machinery,2017,48(8):114-122.
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农药喷施过程中雾滴沉积分布与脱靶飘移研究   [下载全文]
Droplet Deposition Distribution and Off-target Drift during Pesticide Spraying Operation   [Download Pdf][in English]
投稿时间:2016-12-08  
DOI:10.6041/j.issn.1000-1298.2017.08.012
中文关键词:  农药沉积  跨帧技术  靶标植物  生长阶段  随风飘移
基金项目:国家自然科学基金项目(31371963)、江苏省自然科学基金项目(BK20130965)、“十二五”国家科技支撑计划项目〖JP2〗(2014BAD08B04)、江苏省杰出青年教师培育聘专项目(2012256)、江苏省青蓝工程项目和江苏高校优势学科建设工程项目
作者单位
张慧春 南京林业大学 
郑加强 南京林业大学 
周宏平 南京林业大学 
DORR G J 昆士兰大学 
中文摘要:对农药通过空气运输并沉积到靶标植物表面(叶片或其它部位)、地面(土壤表层)以及大气(随风飘移)等不同部分的沉积进行研究。以苦苣菜、棉花和稗草作为靶标植物,取其不同生长阶段(总叶面积分别为15、135、300cm2)作为研究对象。在开路式风洞喷施加有荧光示踪剂喷雾介质,通过清洗并分析植物叶片、地面上放置的聚酯薄膜卡和风洞中悬挂的聚乙烯线测定荧光剂含量,分析不同体积中径、喷雾角、雾滴速度、流量、喷头高度、风速、植物类型、生长阶段等因素时的农药雾化后的分配过程,定量测试不同参数对农药在植物、地面和大气中的沉积比例分配的影响。建立了基于跨帧技术的粒子图像测速系统来增加测速范围,包括激光成像系统、脉冲发生器和分析软件。结果表明,喷雾角、雾滴速度、流量、植物类型等参数对植物、地面和大气等不同部分农药分配比例的影响不大,而雾滴粒径、喷头高度、风速、植物生长阶段对植物、地面和大气等不同部分农药分配比例的影响显著。当雾滴粒径由445μm减小到181μm时,地面上的沉积比例由82.7%减少到57.7%,空气中飘移部分的比例由30%减少到0.8%。当喷雾高度为40~60cm、风速2~4m/s时,农药在植物上的沉积比例都达到13.4%以上。因此,喷施农药时,应尽量使喷雾高度为40~60cm,风速小于4m/s,并根据防治目标、附近环境确定雾滴粒径。当喷施土壤活性除草剂等农药时,应选择产生较大的雾滴粒径,以增加在地面(土壤)上的沉积比例;而对于防治飞行类害虫,农药在空气中飘移部分的比例可以提高防治效果,所以较小的雾滴更加有效。靶标植物本身的特性也会影响农药的有效沉积效率,植物的生长阶段越靠后,叶面积越大,农药在植物上的沉积比例越高,在地面上沉积部分的比例越低,喷施除草剂时,尽量减少药剂在单子叶作物叶片上的沉积,增加在双子叶靶标杂草上的沉积量。选择不同的参数,将导致植物上的药剂有效沉积明显不同,也会引起农药流失部分的明显不同。
ZHANG Huichun  ZHENG Jiaqiang  ZHOU Hongping  DORR G J
Nanjing Forestry University,Nanjing Forestry University,Nanjing Forestry University and The University of Queensland
Key Words:pesticide deposition  frame straddling technique  target plant  growth stage  wind drift
Abstract:Due to great human awareness of environmental conservation and public health, pesticides must be applied in economically viable and environmentally sensitive ways, and it requires deep understanding on the distributions of pesticide application. The distribution is the process occurring immediately after application. When applied, the pesticide can distribute in the following way: loss by wind drift, deposition on leaves or other parts of the target plant and deposition on ground (soil). The sum of these three components (plant, soil and drift) should equal to the amount of spray emitted. However, there are concerns over the intended effect (deposition on plant) and unintended effect (deposition on ground and wind drift) of pesticide application on the effectiveness and risks associated with the use of pesticides. Oriented to distribution of pesticide application, droplet deposition on different parts was measured in the research. Spray deposition was tested by recovery of a fluorescent tracer (pyranine) in the 1.75m wide, 1.75m high and 10m long working section of the wind tunnel. A single nozzle was positioned in the centre of the wind tunnel at a height of 0.6m above the wind tunnel floor and then sprayed moving along the length of the tunnel at a speed of 1m/s. The nozzle moved over the top of the plant so that application amount was the same to a typical spray in agriculture and the pesticide distribution was measured. Mylar cards (plastic) were used to collect the deposition on ground, diameter polythene lines were horizontally mounted to provide an estimate of the wind drift of spray, and the sow thistle plant was put under the nozzle to test the deposition on the target. To evaluate the influence of different factors on spray distribution, the trial was carried out for three plant types (sow thistle, cotton and barnyard grass) at three growth stages (leaf area were 15cm2, 135cm2 and 300cm2, respectively). After spraying, fluorescent dyes were easily washed off the three different samples so good recoveries can be got. The amount of spray on the plant, ground and wind drift was calculated and expressed as a percent (or fraction) of the amount of spray that came out of the nozzle. Based on the frame straddling technique, velocity of droplet was investigated by particle image velocimetry (PIV), and the test system included laser imaging system, pulse generator and analysis software. The influences of droplet size (VMD), droplet velocity, spray angle, flow rate, height of nozzle, wind speed and growth stage of plant on deposition at various parts were investigated. Correlation between different factors and spray distribution (fraction of spray deposited on ground, plant and drift) was calculated to judge the impact. The results indicated that the distribution of the spray was influenced by droplet size, release height wind speed and growth stage. Meanwhile, spray angle, sheet velocity flow rate and plant type had no significant effect on the spray distribution. The ground deposition was the lowest with the fine sprays. It was found that ground deposition from application of pesticides was 57.7% for finer droplet(VMD was 181μm) which was increased to 82.7% for coarser droplet (VMD was 445μm). Deposition on plant surfaces was also found to be more than 13.4% with release height at 40cm to 60cm and wind speed less than 4m/s. For soil-active herbicide, a proportion of deposit on the ground was increased by bigger VMD, and this is a desirable result. For controlling flying pest, airborne deposit can increase chemical’s spread on its body, so smaller VMD was more effective. It was also shown that the proportion of spray depositing on plant surfaces was increased as the plants got larger and the amount depositing on the ground was decreased. The result can be used to effectively aid spray decisions to maximize the effectiveness of pesticides and minimize risks to the environment from chemical spraying activities. Chemical application must be as precise as possible, so populations of unwanted organisms (insects or diseases) can be reduced and less environmental impacts created in the agricultural production. An understanding of the pesticide application process can be utilized to improve the estimate of the distribution on pesticide from a spray operation.

Transactions of the Chinese Society for Agriculture Machinery (CSAM), in charged of China Association for Science and Technology (CAST), sponsored by CSAM and Chinese Academy of Agricultural Mechanization Science(CAAMS), started publication in 1957. It is the earliest interdisciplinary journal in Chinese which combines agricultural and engineering. It always closely grasps the development direction of agriculture engineering disciplines and the published papers represent the highest academic level of agriculture engineering in China. Currently, nearly 8,000 papers have been already published. There are around 3,000 papers contributed to the journal each year, but only around 600 of them will be accepted. Transactions of CSAM focuses on a wide range of agricultural machinery, irrigation, electronics, robotics, agro-products engineering, biological energy, agricultural structures and environment and more. Subjects in Transactions of the CSAM have been embodied by many internationally well-known index systems, such as: EI Compendex, CA, CSA, etc.

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