Ditch-buried straw return (DBSR) is a novel farming system that not only efficiently eliminates the need to burn straw, but also shows positive effects on soil carbon sequestration and crop yields. Implementation of DBSR, however, may penetrate the tillage pan, increasing the risk of N leaching losses. 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 9.09mg 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.