How is fertilizer N adjusted by frequent monitoring with the LCC?
• Farmers can use the LCC to frequently monitor the plant N status of rice. In such case, farmers can take LCC readings at 7 to 10 day intervals beginning at early tillering. Fertilizer N can be applied whenever the leaf color becomes more yellowish green than a critical threshold LCC value. • The critical threshold value for most modern high-yielding rice varieties is intermediate between LCC value 3 and 4 (LCC value 3.5) for transplanted rice and LCC value 3 for wet seeded rice with relatively dense plant population. The critical threshold value can be adjusted for rice varieties. • As a rule of thumb: • During the period between 14 DAT or 21 DAS and panicle initiation, apply the rates of fertilizer N indicated in the table below whenever the leaf color becomes more yellowish green than the critical LCC value. • After panicle initiation up to early heading, apply about 25 kg N ha−1 whenever the leaf color becomes more yellowish green than the critical LCC value.
