Nitrogen form is particularly important in the tomato crop. It is critical to maintain a good balance between ammonium and nitrate forms to maintain fast growth and crop productivity. Over-use of ammonium N can cause problems. Trials confirm significant tomato yield losses of up to one third from use of ammonium in preference to nitrate.
Boron plays an important role in pollen germination and tomato fruit set. Pre-flowering applications ensure good fruit set and full yield potentials are achieved. While boron is quickly taken up from the soil, it is relatively immobile in the plant, so foliar sprays are often more effective.