Using the Leaf Color Chart (LCC) to Manage Nitrogen

A. What is the LCC?

 

The LCC is a simple, easy-to-use and inexpensive tool that can help farmers determine the right time to apply N to rice crops. The LCC is used for monitoring the relative greenness of a rice leaf as an indicator of the plant N status. It helps farmers to optimize N use at profit high yield levels, regardless of the source of N applied – organic (manure, crop residue, etc) or inorganic (e.g., urea, NPK, etc.).

 

The Leaf Color Chart (LCC)

B. Why use the LCC?

 

Nitrogen (N) fertilizer is one of the major inputs in rice production. For efficient use of this input, farmers should apply fertilizer N several times during the growing season to ensure that the N supply matches the crop need for N at the critical growth stages of the crop for greater yield; in this way, fertilizer N losses are minimized. The LCC is a simple and inexpensive tool that can improve farmers’ decisions about N management for rice.

 

C. How to use the LCC?

 

  1. Randomly select at least 10 disease-free rice plants or hills in a field with uniform plant population.

  2. Select the topmost fully expanded leaf from each hill or plant. Place the middle part of the leaf on a chart and compare the leaf color with the color panels of the LCC. Do not detach or destroy the leaf.

  3. Measure the leaf color under the shade of your body, because direct sunlight affects leaf color readings. If possible, the same person should take LCC readings at the same time of the day every time.

  4. Determine the average LCC reading for the selected leaves.

The photos illustrate the use of the standardized LCC to assess leaf N status and adjust N applications to rice:

In photo (a) plants without N application are yellowish. Nitrogen deficiency is confirmed in photo (b) because the LCC reading is between panels 2 and 3.

At low fertilizer N rates in photos (c) and (d) the plants look better, but the low LCC reading still indicates N deficiency.

At higher fertilizer N rates in photos (e) and (f) the plants look well developed and the canopy is closed. The LCC reading is between panels 3 and 4, which is the critical range for most transplanted rice.

 

In photos (g) and (h) plants with a high N rate are dark green. Leaf color is darker than the LCC panel no. 4 indicating a surplus of fertilizer N.

 

 

How to order an LCC?

 

To order a set of LCCs and accompanying documentation, please email r.buresh@cgiar.org or consult the SSNM web site at www.irri.org/irrc/ssnm