Ammonia loss from urea/potassium chloride mixtures applied to sugarcane trash

Trash retention following green cane harvesting has been widely adopted by canegrowers in North Queensland because of its many advantages which include lower crop production costs, improved weed control, moisture conservation and increased soil organic matter. However, the presence of crop residues on the soil surface poses a problem for the placement and efficient use of urea, which is the form of nitrogen fertiliser preferred by most canegrowers. The trash blanket makes it difficult to apply fertiliser into the soil without disturbing the trash cover. Most growers who have adopted trash retention apply urea to the trash surface either by broadcasting or as a band along the stool. The research reported in thsi paper follows the third avenue of controlling ammonia loss and evaluates potassium chloride as a potential material for reducing ammonia volatilisation from surface applied urea.