Urea briquette applicator for transplanted rice

A plunger-type, completely hand-operated applicator prototype, made of polyvinyl chloride (PVC), for deep placement of urea briquettes (UB), i.e., pillow-shaped urea supergranules with edges, in line transplanted rice has been developed for use by small-scale rice farmers. The field evaluation of the applicator was conducted in the Philippines during the 1989 dry season. The applicator consistently placed UB at proper depth (7 to 8 cm), which resulted in low concentrations of urea N (<7 ppm) in about 4 cm of floodwater 1 day after placement. These findings indicated that the prototype worked properly. Average work output of the applicator was 0.20 ha workday^–1 and may increase with practice. The yields of irrigated transplanted rice in the field trials show that agronomic efficiencies of hand-placed UB and applicator-placed UB were equal and were superior to those of split-applied prilled urea.