COFFEE CULTIVATION GUIDE - Coffee Board of India

4. Leaf analysis
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Coffee leaf analysis offers another type of approach in determining the nutrient
availability of a soil and actual nutrient status in the plant itself. In order to determine
the exact nutrient status in coffee plant, leaf analysis is very essential and a useful
tool. The status of nitrogen, phosphorus, potassium, calcium, magnesium, sulphur and
other micro-nutrients can be exactly determined by chemical analysis of the leaves
and deficiency of any of the essential nutrient element can be identified to take
appropriate step in time before it becomes a limiting factor in productivity of the
plant. Simultaneous analysis of soil and complimentary leaf samples gives precise
requirement of nutrients and helps in enhancing the accuracy of fertilizer
recommendation services since these analyses are complimentary to each other.
The leaf analysis can be done ideally during February-March and September-
November months. Fourth pair of leaves from growing tip of Arabica plant branches
from the 2/3 height of the over all plant has to be collected randomly from the field. A
minimum of 25 pairs of leaves from one hectare land is necessary for precise analysis.
The leaf samples should be collected only during the morning time preferably before
10.00 a.m and placed between two sheets of blotting paper and packed in a perforated
polythene bags and sent to the laboratory immediately. The details on the block
history, age of the plant, fertilizers applied and crop harvested should be sent to the
laboratory while sending the leaf samples. These samples are then washed with clean
water and dilute hydrochloric acid to remove any superficial chemicals, dust and
spray particles adhering to the leaf surfaces before processing for chemical analysis.
5. Pre-blossom Bordeaux mixture Spray
Humid cool weather with wind during May to November months, intermittent
showers and sun shine, dry weather during December to March with cloudy weather
(with mist) and drizzling during February-March months are very favourable to the
early appearance of coffee leaf rust disease in plants. Thin or no overhead shade
during the south-west monsoon is also one of the favourable factors for the
development of this disease. In some places, the build up of CLR disease can be seen
during February-March months itself. Generally during February-March months
coffee leaf rust disease will be in its inactivity phase but under favourable conditions
and in the places where very thin shades exist, then this disease can be seen during
February-March months itself. In such areas, the plants have to be sprayed with 0.5%
Bordeaux mixture (please see the Annexure for the preparation of Bordeaux mixture)
or systemic fungicides (Contaf or Bayleton). This spray will prevent the disease
spreading from the older leaves to the new leaves. The areas which are located in
elevations more than 3500 feet are generally not affected by leaf rust disease during
these months. While using the systemic fungicides, care should be taken to see that
banned chemicals are not used for spray (see the Annexure).
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