
TY  - JOUR
A1  - Xu, Xingkai 
A1  - Wang, Zijian 
A1  - Wang, Yuesi 
A1  - Inubushi, Kazuyuki 
T1  - Urea hydrolysis and inorganic N in a Luvisol after application of fertiliser containing rare-earth elements
JF  - Soil Research
JO  - Soil Res.
Y1  - 2003
VL  - 41
IS  - 4
SP  - 741
EP  - 748
KW  - nitrification, rare earths, urea.
UR  - https://doi.org/10.1071/SR02056 
N2  - 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. 
ER  -

