الفهرس 
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Abstract
A major importance of the present work was the evaluation of four
sprayers under laboratory and field conditions in comparison with
conventional motor sprayer.
Laboratory data on spray parameters showed that flow rate
significantly varies depending on the type of machine tested. Such
difference may be attributed to either drift loss, very fine droplets
produced or meeting of such fine droplets with bard surfaces at variable
spray heights.
The present study also revealed that the effect of air charging with
electrostatic forces, centrifugal energy and hydraulic energy is
significantly correlated with the flow rate, droplet formation and droplet
distribution in case of knapsack motor sprayer Agrimondo with shear
nozzle, knapsack motor sprayer Agrimondo with electrostatic unit, rotary
spinning sprayer Matabi, hydraulic Matabi sprayer and conventional
ground motor sprayer. Similar results have been reported by Burt and
Smith (1974), Fraser and Exisenklam (1956) and Hindy et al. (1991).
A rotary spinning disc Matabi in laboratory can be treated as a
demonstration of the rotary atomizers pattern through using a narrow
restrictor. Also, the results demonstrated the relationship between
working hours and both R.P.M and spray deposits on watery sensitive
cards. The daily working hours of this sprayer depends on the type of
battery, the physical properties of the spray solution used ( viscosity, and
surface tention), and the ambient climatic conditions. The proper spray
height for Matabi spinning disc was 0.5m, as recommended at the present
time. Both the tested rotary normal pneumatic atomizers and pneumatic
atomizer with electrostatic unit produces a rich number of fine droplets.
With using spray gun and hydraulic Matabi sprayer as hydraulic nozzles
because of successive falling of operating pressure during spraying
operation and the low quality of the used nozzles.
Data showed that increasing flow rate of pneumatic motor sprayer
is more valuable in case of full tank capacity than half tank capacity at
three air hose positions: vertical, upper 45º and down 45º. The flow rate
of pneumatic sprayer depends on amount of air pressured on liquid
surface, the gravity and the r.p.m of motor sprayer. All these factors
affect flow rate values besides the physical properties of the liquid used.
Also, swath width of pneumatic motor sprayer depends on the r.p.m
motor, physical properties of sprayed solution and the ambient climatic
conditions during execution of the test. According to the spray deposits
quality, the tested atomizers can be arranged in a descending order from
the best to the worst as follows:
1-Rotary spinning disc Matabi sprayer (18 L/fed)
2- Knapsack motor sprayer Agrimondo with charging unit (42 L/fed)
3- Knapsack motor sprayer Agrimondo with shear nozzle (79 L/fed).
4- Hand held hydraulic Matabi sprayer (56 L/fed).
5- Conventional ground motor sprayer (578 L/fed).
B. Field evaluation of the spray technique
B.1. First season experiment (2017)
The spray bulk produced by five spraying techniques was
evaluated depending on satisfactory spray coverage on target plants as
well as lost spray on the ground between plants. It should be taken into
consideration that the drift spray counts were not included in this study.
The best equipment saving lost spray on ground, is electrostatic
Agrimondo sprayer with 15.6% lost spray. The worst equipment is the
conventional ground motor sprayer with 44.6% lost spray on ground.
Data confirmed that there is a positive relationship between rate of application and the spray lost on ground between the treated plants. Also,
20% of the droplets were deposited on the lower surfaces of knapsack
motor sprayer with electrostatic unit.
Spray homogeneity resultant from the tested equipment can be
arranged in a descending order from the best to the worst as follows, a
knapsack motor sprayer with charging unit, knapsack motor sprayer with
normal unit, Rotary spinning disc Matabi sprayer, hand held hydraulic
Matabi sprayer and conventional ground motor sprayer. However, from a
conventional view, the equipment’s can be arranged in a descending order
as follows, knapsack motor sprayer Agrimondo with electrostatic unit and
with normal unit 11.6 fed/day for both of them, conventional ground
motor sprayer 4.4 fed/ day hand held hydraulic Matabi sprayer 3.4
fed/day and rotary Matabi spinning disc sprayer 2.3 fed/day.
B. 2. Bioresidual activity of Marshal on thrips tabaci lind. on onion
crop during 2017 season
Bio residual data showed that, the best efficiency of Marshal with
high value of reduction percentages was produced by knapsack motor
sprayer Agrimondo with charging unit, followed by knapsack motor
sprayer with normal unit, handheld hydraulic Matabi sprayer
conventional ground motor sprayer and Matabi rotary (spinning disc)
sprayer. The optimum droplet spectrum for controlling (thrips tabaci
lind.) on onion crop must be at least 250droplets/cm² with an average
droplet size of 50μm (VMD) to produce satisfactory control.
B. 2. Second season experiment (2018)
B. 2. 1. Spray quality
Similar results were obtained using two insecticides with
recommended and ¾ recommended dose using the same five tested
spraying techniques. So, data on satisfactory spray coverage, lost spray
on ground between plants and drift spray outside the treatment with downwind were collected. Data showed that electrostatic Agrimondo
sprayer produces the ideal spray quality on onion crop, the highest
reduction of lost spray on ground (15.6%) and the least spray drift outside
the treatment. The worst equipment is the conventional ground motor
sprayer with 44.6% as lost spray on ground due to big droplets, amount of
water and the high operational pressure used.
B.2.2. Bio residual activity of certain insecticides against thrips on
onion crop during 2018 season 2018
Data showed that, there is a relationship between decreasing
droplet sizes (VMD) and increasing number of on the efficiency of
insecticides used against Thrips on onion. It must be controlled with low
volume spraying machines ranging from 18-42 L/fed. That can be
accomplished through using electrostatic and pneumatic energy or both of
them or by using centrifugal energy by spinning disc sprayer. The worst
quality spray and poor efficiency of bio residual activity of insecticides
sprayed is produced through using hydraulic energy through ground
motor spray or hand held hydraulic spray.
Data also showed that there are no significant differences between
recommend doses and ¾ recommend doses with recent equipment. That
can save 25% of the insecticides prices used in controlling Thrips and
saves agricultural environment from pollution.
On the other side, we found that there is no significant differences
between initial spraying after 24 hours and residual spraying after
spraying 7 days and 12 days by recent sprayer and hydraulic Matabi
sprayer.
Also, electrostatic sprayer showed the lowest drift spray results, but
the biggest drift spray results were produced by rotary Matabi spinning
disc.