1. At 14 days after transplanting (DAT) or 21 days after direct wet seeding (DAS), randomly select 10 healthy plants in your field where plant distribution is uniform.
2. Compare the topmost, fully expanded, and healthy leaf of each of the 10 plants with the LCC. Place the middle part of the leaf on top of the LCC’s color strips for comparison. Do not detach the leaf. Take readings at same time of the day (8-10 AM). Do not expose the LCC to direct sunlight during reading s. The same person should take the first up to the last LCC reading.
3. If six (6) or more of the 10 leaves have readings below the critical LCC value, apply N as given below.
4. Repeat LCC readings every 7 days for 110-130-day rice crops and every 10 days for more than 130-day crops until first heading. Different sets of 10 leaves can be used for each weekly or 10-day reading.
5. If basal fertilizer with N (DAP or NPK compound) is applied 0-14 DAT or 0-14 DAS, the first LCC reading is done at 21-25 DAT or 28-30 DAS instead of 14 DAT or 21 DAS.
1. Apply 25 kg Urea per acre at the time of sowing of maize.
2. Take readings of ten randomly selected maize plants, by matching the color of the first fully exposed leaf from the top with the leaf color chart (LCC) starting from 21 days after sowing of maize till initiation of silking at 10 day interval.
3. Match the color of maize leaves with LCC shade 5. If 6 or more leaves out of 10 leaves are lighter than the specified threshold, apply 25 kg urea per acre. When color of 5 or more leaves is equal to or darker than the specified threshold no urea should be applied.
4. Always match the color of leaves with LCC in the shade of your body to avoid direct sunlight.
5. Use of LCC should be discontinued after silking in maize and no urea should be applied afterwards.
1. Apply basal dose 55 kg di-ammonium phosphate (DAP) per acre.
2. Apply 40 kg urea per acre for timely sown wheat and 25 kg urea per acre for late sown wheat with first irrigation.
3. Match leaf colour of youngest fully exposed leaf from the 10 randomly selected insect/disease free wheat plants from each field with LCC before 2nd irrigation.
4. If the greenness of 6 or more out of 10 leaves is less than shade 4 on LCC, broadcast 40 kg urea per acre for timely sown wheat and 25 kg urea per acre for late sown wheat with second irrigation.
5. If greenness is equal to or more than shade 4 on LCC apply only 25 kg urea per acre for timely sown wheat and 15 kg urea per acre for late sown wheat with second irrigation.
6. Always compare colour of the wheat leaf with LCC under shade of your body.
R & D done by Punjab Agricultural University, India.