Introduction          Background Research        Objective and Hypothesis        Materials and Procedure
           
   Results : Variables Related to Leaf Surface        Results : Variables Related to Liquid

Results : Variables Related to Method of Application         Conclusions and Final Thoughts

 
 
 
Conclusions
Leaves are hydrophobic and have surface characteristics such as hairs, ridges, and bumps. These two properties are the most important tools in reducing runoff. A large drop on a leaf with closely spaced hairs, bumps, or ridges will roll off the tips without wetting the leaf surface. A small drop on such a surface will be trapped between the hairs, ridges, or bumps (Experiment 1 and 5).
 
Therefore the type of leaf surface has impact on the type of spray which should be used. A leaf at a greater angle to the ground will show greater runoff. It would therefore be better to spray such leaves at near horizontal or below horizontal angles (Experiment 2). A layer of dust evens out the surface irregularities and also absorbs a fraction of the liquid, thus reducing runoff (Experiment 3).
 
However, single application or multiple applications for the same volume do not effect the percentage of runoff (Experiment 4).
 
For most efficient results, smaller particles sizes should be used with surface application methods. Due to spray drift, it is necessary to use larger particle sizes in aerial application. Therefore, surface application is most efficient as the small particle has just enough energy to reach the surface. (Experiment 5)
 
The most effective way to control runoff is the use of surfactants. Reduction up to 80% can be achieved by adding a suitable surfactant to the spray. Nonionic surfactants are most effective in reducing runoff. It was observed that the nonionic solution formed a long filament before it eventually ran off the surface of the leaf suggesting that it has a high elongational viscosity (Experiment 6).
 
Lower concentrations of surfactants tend to be more efficient in reducing runoff more most leaf surfaces (Experiment 7)
 
In this context, an environmentally friendly surfactant will be an ideal solution. Initial experiments on starch demonstrate its potential in reducing runoff by half. (Experiment 8).
 
Creating a Java Program
A program was created using Java with a database of common plants and an “enter plant characteristics” option. The user could input data for the leaf surface (number of hairs, ridges, bumps) or browse by plant listings. Dependent on the surface characteristics, information regarding particle size, volume, surfactant, surfactant concentration etc. was displayed.
The project deals with variables which can be controlled in a lab setting. Actual applications of pesticide sprays in the field are also effected by other variables such as weather, age of plant, density of plantation, plant structure etc. Spray drift is an important factor in actual field conditions which has a bearing on the particle size. Field studies are required to identify such variables and evaluate their impact on runoff.
Limitations