It contains ammonium and nitrate nitrogens together. Nitrate nitrogen is quickly taken up by the roots during the rapid growth and yield periods of plants. Most of the nitrogen in the form of ammonium is retained by soil particles, which is then converted into nitrate nitrogen by nitrogen bacteria, thus preventing plants from suffering from nitrogen deficiency. CAN fertilizer is used as a top fertilizer on all plants, including grains such as wheat and barley, at hoeing and before irrigation. It should not be used in paddy farming.