Brochure Cover Art

Hello, We need a new Graphic for the cover of our product brochure. I have attached images we have used in he past to give an idea of what we use to do. the product is a water condition used in agriculture to treat the spray water of herbicides and pesticides. One of the major things it does is make the water drops spread out on the leaf, covering more surface area, we would like to indicate this in the graphic if possible. The product also has a color indicator in it that turns the water pink what the water has optimal. this should also appear in the image some how. If illustrations are used they need to me realistic looking not cartoon. The leaves and plants need to me crop species (corn, wheat, tomato soybean etc.)