Deep placement of nitrogenous fertilizer (N) is an alternative for increasi
ng the N use efficiency of wetland rice besides minimizing the adverse effe
cts of fertilizers on the environment. It has been found to limit the loss
of N due to surface runoff, leaching, volatilization and denitrification th
at lead to reduction in applied N. Different machines as well as N material
s (granular, urea supergranules or briquettes, liquid N) have been introduc
ed for this method. Although deep placement of fertilizer increased N use e
fficiency in rice-growing countries, the machines meant for this purpose ha
ve not been well accepted due to problems in performance consistency and co
mmercial unavailability or extra cost of recommended materials. Despite the
se problems, however, several prototypes have shown potential but their acc
eptance maybe limited unless these promising mechanisms are adapted into a
system that addresses the field and socio-economic conditions of Asian farm
ers. A fertilizer management system that combines machine deep placement, c
rop establishment and farmers' timing of application using the commercially
available materials could enhance adoption of the technology. Further refi
nements of the promising devices as well as addressing farmers' constraints
are, thus, recommended for a better acceptance of deep placement in the ri
ce-growing countries of Asia. (C) 2001 Silsoe Research Institute.