A. T. M. S. HOSSAIN1, F. RAHMAN1, M. S. A. TALUKDER2 and B. K. SARKAR3
1Scientific Officers, Soil Science Division, BRRI, Gazipur. 2 Scientific Officer RFS Division, BRRI, Gazipur, 3Scientific Officer, BRRI R/S, Bhanga, Faridpur, Bangladesh.
ABSTRACT
The field experiments were conducted at Bangladesh Rice Research Institute (BRRI), Regional Station, Bhanga, Faridpur during Boro season of 2000-2001 and 2001-2002 to compare the Leaf Color Chart (LCC) technique with the conventional split application of prilled urea (PU) for MV rice (BRRI dhan29). Treatments consisted of 4 different N management viz. BRRI recommended N-split (124 kg N/ha), two LCC threshold levels, LCC-4N and LCC-5N and control. Results in Boro 2000-2001 revealed that the LCC based N treatment (LCC-5N) gave the highest yield (7.2 t/ha) and consumed only 90 kg N/ha applied in 3 equal splits where as BRRI recommended dose yielded 6.8 t/ha and consumed 124 kg N/ha applied in 3 equal splits. During Boro 2001-2002, the LCC based N treatment (LCC-4N) gave the highest yield (7.9 t/ha) which was identical with that of the LCC based N treatment (LCC-5N), 7.6 t/ha and BRRI recommended N split (7.3 t/ha). It was found that both the LCC based N treatments (LCC 4 and LCC 5 N) consumed only 90 kg/ha applied in 3 equal splits where as BRRI recommended dose consumed 124 kg N/ha applied in 3 equal splits. This indicated that the LCC based N management appears to be more efficient in utilizing N-fertilizer than conventional split application. The AEN values were appreciably high for LCC-based N treatment, in contrast with BRRI recommended dose. Due to higher grain yield with lower N application, LCC-based N management gave higher AEN and saved about 34 kg N/ha for BRRI dhan29 in Bhanga region.
Key words: Leaf Color Chart (LCC) prilled urea (PU), agronomic efficiency of N (AEN), recovery efficiency of applied N (REN).