Information
Level 4 Data summaries and links to related documents and reports
Key findings (brief)
From a catchment prospective the most significant finding during the study period was that the concentrations of nutrients and sediment in runoff water were low and that other loss processes were more significant.
Nutrient loss mechanism
Runoff is the most visible loss mechanism. However, when soil erosion is minimised the nutrient concentration in runoff is low. The total export of nutrients can still be high due to naturally high rainfall in the region.
Sugarcane
The greatest potential for nitrogen losses from sugarcane occurs in the plant crops. This is mainly due to soil disturbance leaving a bare unprotected surface and also the lack of an established root system in the plant crop.
Banana
Large drainage losses of nitrogen and potassium are associated with basal applications of nutrients in the plant crop. Average leaching losses under the ratoon crop are generally lower than those recorded for the plant crop due to the established root system being more efficient at nitrogen uptake.
Dairy Pastures
Volatilisation is the major pathway for nitrogen loss from pastures and can be considerable when urea fertiliser is applied at the surface. Runoff from the pasture was minimal. with loss rates of nitrogen and phosphorus <0.5 kg/ha in most years. The leaching of N and P have been small in all years.
Rainforest
Runoff from the rainforest land use was minimal. Mineral nitrogen concentrations measured in drainage water were similar to the concentrations measured under dairy pastures where little nutrient was moving below 60 cm in the oil profile
Key tables and figures extracted from data, literature and miscellaneous publications