New Zealand Journal of Agricultural Research abstracts
Nitrogen leaching losses from different forms and rates of farm
effluent applied to a Templeton soil in Canterbury, New Zealand
K. C. Cameron
H. J. Di
Centre for Soil and Environmental Quality
P.O. Box 84, Lincoln University
Canterbury, New Zealand
Abstract The leaching losses of nitrogen from a
range of farm effluents and wastes, including pig slurry, dairy pond
sludge, farm-dairy effluent, and cow urine are compared on a Templeton
fine sandy loam. At similar rates of application, leaching losses
decreased in the following order: cow urine>pig slurry>farm-dairy
effluent>dairy pond sludge. The susceptibility to leaching is
determined by the forms of the N in the waste, and a high N:C ratio
alone is not an adequate predictor of leaching intensity. Nitrate is
most susceptible to leaching, followed by ammonium and organic forms of
N. Splitting the applications of effluent into two or four portions
applied at different times reduced the overall quantity of nitrate
leached by c. 30%, depending on the waste. Similarly, reducing the
overall rate from 400 to 200 kg N/ha also reduced the N leaching
loss by c. 30%, depending on the particular waste. It is
recommended that the land application of farm waste be based on a
knowledge of the propensity of different kinds of wastes to contaminate
groundwater, especially with nitrate-N. An effective mitigation
technology to reduce nitrate leaching from grazed pasture soils is to
treat the soil, including cow urine areas, with a nitrification
inhibitor, e.g., dicyandiamide (DCD), which has been found to reduce
nitrate leaching losses by 60%, decrease nitrous oxide emissions by
over 75%, and increase pasture yield by over 10%.
Keywords farm; effluent; nitrate; leaching; urine;
waste; nitrification inhibitor; pasture; water quality
A03065; Received 24 October 2003; accepted 10 June 2004; Online
publication date 15 December 2004
New Zealand Journal of Agricultural Research, 2004, Vol. 47:
429–437
0028–8233/04/4704–0429 © The Royal Society of New Zealand 2004
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