We use an integrated approach
to measure the fate of 15N fertilizer and to document the major loss
pathways in situ rather than by using individual measurements of
loss processes reported in other studies to understand N behavior
in these 2 rotations and thus attempt to control the environmental
risk.Weex plain the reasons for the large external Ninputs currently
practiced in these intensive management systems and suggest
strategies for balancing N management by applying knowledge based
optimum N fertilization techniques.
This study examines double-crop rotations, which are 2 of the
most intensive agricultural systems worldwide and are widely
practiced in Asian countries. The frequent alternation between
flooding and draining the rice/wheat rotations led to significant
changes in soil N transformations as compared with upland crop
rotation. In addition, the extremely high external synthetic N inputs