Whenever any farmer sprays the field with pesticides, only 2 percent of it remains with the plants while the rest jumps or bounces to the ground and becomes a part of the runoff that then flows to canals and rivers polluting them. However, a team of researchers working in MIT recently fixed it.
Figure 1: Spraying plants
The team fixed it by using a smart combination of two cost-effective additives in the spray. The research team discovered that these can reduce the amount of liquid that bounces to the ground and leads to pollution. The paper on this research was written by research scientist Seyed Reza Mahmoudi, a former postdoc. Md Nasir Hyder, and graduate student Maher Damak. The earlier trials for reducing the bounce of droplet over ground depended on other harmful additives that includes soap like chemicals and surfactants. These substances would then reduce the surface tension of droplets leading to their better spread over the plant.
However,the tests prove that these efforts lead to very small amount of improvement, most speedy droplets bounce off here and there while surface tension change is taking place. The surfactants also lead to formation of smaller droplets that are blown away by wind more easily.
The approach to this subject uses two other additives. The spray gets divided into two portions where each gets a different polymer substance. One grants negative charge to the solution while the other one leads to formation of positive charge. When the two reverse charged particles meet on leaf’s surface they stick with each other leading to formation of a hydrophilic “defect”. It also increases the retention of other droplets. There are many plants whose leaves are hydrophobic that can lead to bouncing of droplets. But the makers found solution to this problems by creating very small hydrophilic bumps over the leaf surface that counteracts this tendency very strongly.