We
therefore determined whether N retention could be increased by DBSR in order to reduce the risk of
N loss to the environment. A four-year field experiment and a complementary greenhouse experiment
were conducted to test the effects of DBSR on N retention in a rice-wheat rotation system. We found
that DBSR altered the spatial distribution of fertilizer N. N content was significantly increased above but
reduced below the straw layer in the field experiment. The greenhouse experiment further confirmed
the N retention effects by the straw layer. In theory, a maximum of 9.09 mg urea-N could be adsorbed by
one gram dry wheat straw. Our results suggest that DBSR has the potential to increase N retention in the
soil, thus increasing crop uptake and minimizing leaching N loss in the rice-wheat rotation system.