
%0 Journal Article
%A Xu, Xingkai 
%A Wang, Zijian 
%A Wang, Yuesi 
%A Inubushi, Kazuyuki 
%T Urea hydrolysis and inorganic N in a Luvisol after application of fertiliser containing rare-earth elements
%J Soil Research
%D 2003/07/18
%V 41
%N 4
%P 741-748
%K nitrification, rare earths, urea.
%R https://doi.org/10.1071/SR02056
%U https://www.publish.csiro.au/paper/SR02056 
%X In recent decades, Chinese agriculturists have used rare-earth-containing fertilisers as basal fertilisers together with N fertilisers (e.g. urea). We studied urea hydrolysis and its hydrolysis products in a laboratory experiment using urea-N fertiliser with rare earths at rates from 0.5 to 50% (w/w). The results indicated that application of rare earths at a high rate could result in a short-term inhibition of urea hydrolysis and an increase in soil (NH4+ + NO3&#8211; + NO2&#8211;)-N content. When the application rate of rare earths was higher than 5% of the applied urea-N (corresponding to 10 mg/kg soil), soil exchangeable NH4+-N content increased significantly following the hydrolysis of the applied urea. Increasing the application rate of rare earths appeared to reduce the content of soil urea-derived (NO3&#8211; + NO2&#8211;)-N. A substantial reduction in soil pH was found immediately after application of rare earths and urea. We conclude that application of rare earths at &#62;10 mg/kg may lead to a substantial increase in the content of urea-derived N in the soil, via the inhibition of urea hydrolysis and nitrification. 
