Plant training, pruning and rejuvenation are essential maintenance operation in coffee plantations for achieving economic and potential yields. This is a labor intensive and skilled process which differs from place to place, for systematic management in coffee, a proper scientific understanding of the growth pattern and architecture/morphology of the coffee plant is essential. Coffee is very sensitive plants and needs timely care maintenance to make it sustainable productive for long time.
Training of Bushes
Training of coffee bush is necessary to give it a proper shape and also for restricting the plants growth at desirable height for adoption of effective cultural practices. It leads to a strong framework and promotes the production of bearing wood. Generally two types of training, viz., single stem and multiple stem system are adopted for coffee throughout the world.
Single Stem System
Single stem system of training is more suitable under Indian conditions where coffee is grown under shade. When trained on single stem, the height of the bush is restricted at a convenient height by a process called topping/capping. Topping helps in diversion of food material to thicken the main stem and primary branches and facilitates lateral spreading of plants. Single stem trained plants provide a good ground cover which protects the soil from erosion and minimize the soil fertility loss. These plants will have good shape as well as bush frame work, and they can be easily attended with farm activities like handling, pruning, spraying with plant beyond the basal node to prevent splitting of main stem due to crop load. The new suckers arising from the main stem are removed periodically. The topping heights prescribed for different coffee types are as follows:
Tall Arabica varieties (2 tier system)
- First tier :0.75 m (2.5 ft)
- Second tier :1.4 to 1.5 m (4.5 to 5 ft)
The second tier should be raised after 3 to 4 harvests when the primary branches start overlapping between the plants.
- Dwarf Arabica (single tier :
0.9 to 1.5 m (3 to 5 ft)
- Robusta (single tier) :
- to 1.2m (3.5 to 4 ft)
Pruning of single stem system
It is well established that in evergreen plants like coffee which produce crop on current season/one year wood, require more regular pruning than those which bear crop on older wood. Pruning is essential to maintain proper balance between vegetative wood and cropping wood and to direct the vigour of plants into the cropping woods. Pruning reduces the biennial bearing habits of coffee by preventing overbearing and exhausting in any particular year; permits entry of sunlight and aeration to the lower parts of the bushes, thereby enhancing ripening: minimizes the build-up of pests and diseases; keeps the bushes in a manageable shape and there by improves the efficiency of field operations like spraying, swabbing, harvesting etc.
Time of pruning: The main pruning should preferably be commenced 3 to 4 weeks after completion of harvesting and could be continued till the onset of monsoon. The 3 to 4 weeks gap is necessary to allow recuperation of plants after relieving the crop load. If dry conditions prevail, it is better to delay the pruning till receipt of few summer showers measuring about 100 mm rainfall, especially in lower elevations. The bushes suffering from exhaustion/die-back should be pruned only when there is sufficient moisture in soil or else they fail to put forth new sprouts.
Method of pruning: In India, different methods of pruning like light pruning and hard cyclic pruning have been studied under different conditions like summer and monsoon. Generally, light pruning is practiced in single stem and cyclic and rock-n-roll pruning is advised for multi-stem system.
Light pruning: Light pruning involves removal of old, unproductive, criss-cross branches, lean, lanky and whippy wood, diseased and damaged branches as well as branches growing towards main stem and touching the ground etc. in coffee trained on single stem system, regular light pruning is desirable. Light pruning encourages the growth of new branches which would become next year’s cropping wood. This is applicable to both Arabica and irrigated Robusta coffee. In case of un-irrigation Robusta light pruning may be necessary only in alternate years. Gormandizers which grow in a semi-erect manner on primary branches tend to suppress the lower cropping branches if allowed to grow and so they should be removed during main pruning. If gormandizers are allowed in one season due to valid reasons, they should be invariably removed during next pruning season.
In any given field, all the plants may not require same degree of pruning. Based on individual merit, the bushes need to be pruned. The bushes affected by die-back require hard pruning to build up new wood for future crops, while the bushes with goods complement of cropping wood require only light pruning. The bushes which had carried good crop and exhausted may require more intense pruning than those which had less crop and suffered least exhaustion. While pruning, adequate care should be exercised not to remove the primary branches up to the main stem, because once lost they can never be severed up to their base. Multi-location research carried out by Central Coffee Research Institute for nearly three decades has led to a conclusion that light pruning every year is most ideal for coffee in India.
Hard pruning: If the bushes are in prime bearing age and have lost their framework due to damage caused during shade lopping or irregular pruning pratices, they can be brought back to shape by hard pruning, provide, the primary branches are intact. In hard pruning, the secondary branches are removed to encourage new branches. In case of Robusta, all the primary branches could be pruned back at about 30 to 60 cm from the main stem to encourage production of new secondary branches. In such case, it is important to allow a ‘lung’ branch for maintaining physiological activities like translocation and photosynthesis. Hard pruning should be undertaking only when the atmospheric conditions are cooler and when the soil is moist after few summer showers for better wood growth.
Harding, centering and desuckering
‘Harding’ is a thinning operation carried out after the main pruning, in one or two rounds in a year, depending upon the growth habit of the plants. The first round of handling is done during June-July, by which time sufficient new flush is produced consequent to main pruning. The handling operation is suggested mainly to thin out the new flush to a desired level. While thinning out new branch on either side of the node, resembling a fish bone pattern. If the vigour of the bushes is not satisfactory, only one new branch could be retained at each node in alternate manner. Such well spaced branches will develop into healthy cropping wood for the following season. At the time of handling, the criss-cross, inward growing branches (towards main stem ) and semi-erect growing (gormandizers) branches should be removed irrespective of their vigour and growth of bushes, handling may have to be repeated during September-October. In North-East monsoon influence area like Andhra Pradesh and Odisha, where excess vegetative growth is noticed in coffee bushes, two to three rounds of handling may become necessary in a year.
At the time of handling, all the new flush arising within 10 to 15 cm radius of the main stem should be removed. This operation is called as ‘centering’, which helps in penetration of light and aeration to the lower branches of the coffee bushes. Generally at the estate level, centering is done extensively which result in a wife gap of more than 30 cm around the main stem, at the center of the bush. Too much opening of center of bushes would expose the main stem which provides an ideal condition for white stem borer attack. In white stem borer endemic areas, centering should be kept to the minimum extent possible, depending on the growth pattern of the varieties under cultivation.
‘Desuckering’ should be done periodically by removing all suckers on the main stem from time to time. This operation should be carried out along with the handling and centering operations and subsequently during other operations like weeding, especially prior to manuring.
In case of Robusta, which is less prone to die back associated with over bearing, it is sufficient to remove the suckers and shot hole borer affected branches regularly throughout the year. Once in two to three years it may became necessary to carryout light pruning as described for Arabica. However, in case of irrigated Robusta coffee, regular light pruning would be necessary every year to obtain maximum benefit from irrigation.
Multiple Stem System
The multiple stem system is generally practiced for coffee plants grown in open conditions, as in some countries of Africa, Latin and South America. In this type of bush training, multiple or more than one stem is allowed. Generally the plants trained on multiple stem system are left un-topped and the pruning in such cases is usually restricted to stumping of multiple stems in a cycle of three to four years either by cycle pruning or Rock n’ Roll pruning. Under Indian conditions, multiple stem system is yet to be standardized.
Cyclic pruning
Cyclic pruning is practiced after establishing the 1st tier by topping the main stem at about 0.3 m height. After topping, one sucker is allowed from topped wood during 1st year, 2nd year and 3rd sucker in the 3rdyear as shown in the figure. Similarly, 1st sucker will be removed during 4th year by allowing one new sucker, 2nd sucker in the 5th year and 3rd sucker in 6th year. Every removed sucker. Like this pruning will be practiced in cyclic manure after the harvest of crop.
Rock-n-roll pruning
Rock-n-roll pruning is practiced after establishing the 1st tier by topping the main stem at a height of about 0.3 m. subsequently, during the 1st year, 2 to 3 suckers are allowed to grow in the 1st, 4th, 7th rows etc., during the 2nd, 5th, 5th rows etc., and during the 3rd, 6th,9th rows etc. during the 4th year all suckers in the 1st,4th,7th rows etc., will be pruned and replaced with new suckers. This cycle will be continued in the subsequent years (Fig).
Rejuvenation
The coffee bushes which are badly damaged by falling branches during shade regulation or have gone out of shape due to irregular pruning can be rejuvenated by collar pruning/stumping. They are collar pruned/stumped at about 30 cm from the ground at a 45 angle facing East or North-East. This should be done after the first few summer showers in March-April. The cut surface is treated with Bordeaux paste (1 kg CuSO4 and 1 kg lime dissolved in 4.5 1 of water) to prevent rotting of the cut surface. However, failure of suckers production occurs in old Robusta plants to an extent of 20% to 30%. To induce sucker production a spray of IAA200 ppm in combination with 1% DMSO (200 mg IAA and 10 ml Dimethy sulphoxide in 1 1of water ) could be given on the collar pruned stamps. A vigorously growing sucker is allowed to grow from 2.5 cm below the cut surface and is trained to from a single stem canopy.
Do’s and don’ts in training and pruning of coffee
- Follow prescribed topping heights
- In marginal and wind prone areas, lower topping heights are apt
- After topping, do not allow suckers on main stem
- Prune the plants preferably after harvest if sufficient moisture is present in the soil
- Prune the plants preferably after shade regulation
- In dry hot condition, delay pruning till the receipt of a few summer showers
- Bushes suffering from exhaustion and die-back are to be pruned only when there is sufficient moisture in soil
- Practice only light pruning involving removal of old, unproductive wood, criss-cross branches, branches touching the ground, lean and lanky branches, dead and broken branches and pest and disease affected branches.