Changing the Face of Cocoa Plantations – Part 1Annelle Holder-John and T.N. Sreenivasan, 2015.
Edited by Dr. Marissa Moses and Dr. Lambert Motilal (Cocoa Research Centre, The UWI St. Augustine Campus) of a Paper presented at the International Fine Cocoa Innovation Centre Conference & Symposium, Trinidad and Tobago, March 23-24, 2015.
To maximize yield, scientists at the Cocoa Research Centre are re-thinking the layout of cocoa plantations.
The day I moved to the Santa Cruz Valley in North Trinidad was the day I saw my first cocoa plantation. However, short trees bowed by heavy vines, covered in moss under a dark canopy of towering immortelles, were hardly an inviting sight to a five year old still clutching her cabbage patch doll. I didn’t know it then but it was an abandoned cocoa plantation. Fast forward twenty years and we land in a “different” Trinidad, one in which there is a thrust for economic diversification away from oil and natural gas. Trinidad and Tobago is experiencing a new interest in cocoa plantations and along with this restored national significance, the Cocoa Research Centre is investigating a new layout of the traditional cocoa plantation.
A plantation is a large piece of land where one crop is intentionally planted for commercial purpose. Plantations have several different methods of laying out planting material, but the main goal is to have the optimum number of trees per hectare, with an agronomic system that is self-sustaining. Under such a system, we could harvest 4 tonnes of cocoa per hectare as compared to 0.25 tonnes that is normally obtained in Trinidad. How does one accomplish such an intricate balance of factors to produce this high yield?
Let us first consider the planting density.
One might instinctively think that more is better if you want high yields, but as with most biological systems, overcrowding increases disease incidence. Intermingled tree canopies also make it difficult to harvest pods and restrict the use of mechanisation. Getting the optimum planting density is therefore essential, and further customisation may be needed if the land has any unique physical features that cannot be modified.
The traditional spacing for cocoa is 4 m x 4 m which amounts to roughly 625 trees per hectare, but there have been subsequent trials to investigate maximum planting densities in cocoa. In the 1990s, a 1.8 m x 1.8 m planting system of Trinidad Selected Hybrids was evaluated and in the initial production years, it yielded three times more than a spacing regime of 3.6 m x 3.6 m. However, the caveat to such exceptional findings is that researchers believe that an ideal micro-climate for pollinators, optimum nutrient/water recycling as well as two TSH varieties outperforming the other varieties, were also contributing factors to higher yields. A study in Brazil also experimented with a similar planting density of 2 m x 2 m and although initially promising, the yields dropped sharply by the 11th year from disease incidence. It was found that a density of 4 m x 4 m (with one tree in the diagonal cross) had greater yields in the latter half of the study as compared to the higher density plantings. Similarly to the Trinidad experiment, some varieties were more adapted to higher planting densities than others.
So should we change the varieties we are cultivating?
Depending on your market, it may not be possible to change your planting material. However, in order to fully benefit from a high planting density system, selected varieties should be adapted to high density planting. Whichever variety you however propagate, the protection and proliferation of cocoa pollinators such as the midge, is recommended to promote more fruiting. The care of pollinators is often overlooked in cocoa plantations. Well maintained midge pollinator hives within the fields, can be made by incorporating the pseudo-stem of the banana plant (Musa sp.) or cocoa husks.
How do we cope with extreme dry seasons?
Cocoa thrives in well drained soils, and is susceptible to water stress which weakens the tree. Water stress increases flower/cherelle drop and enhances the susceptibility to termite, cocoa beetle and borer. The midge population is also drastically reduced in the dry season as their moist habitats dry up. To combat such conditions, irrigation of cocoa trees will be evaluated by researchers for their effect on yield. It is envisioned that the controlled delivery of water will have an advantageous effect as seen in vegetable cultivation.
To shade or not to shade?
If irrigated and fertilized, cocoa trees do not require shade. However, the use of limited shade protects the young cocoa trees. Pigeon pea (Cajanus cajun) and plantains (Musa sp.) are both crops which can be used as temporary shade, and is also a source of revenue. Peewah (Bactris gasipae), ice-cream bean (lnga edulis), and coconut (Cocos nucifera) are marketable crops which can be used as permanent shade. Management of permanent shade is however vital, since too much shade will decrease flowering and render the use of fertilisers ineffective. In windy areas, the use of a windbreak to protect trees is also recommended to decrease damage to foliage and desiccation of young plants. Once again selection of crops which can provide income is advised. Tree crops which can provide both wind protection and have commercial value include bayleaf (Pimenta racemosa), neem (Azadirachta indica) and wax apple (Syzygium samarangense).
In 2017, the feasibility of these and other self-sustaining innovations will be evaluated in a large model orchard at the International Fine Cocoa and Innovation Centre, Trinidad.
To read more about such studies we recommend
- Goenaga R., M. Guiltinam, S. Maximova, E. Seguine and H. Irizarry (2015). ‘Yield performance and bean quality traits of cacao propagated by grafting and somatic embryo-derived rooted cuttings’. Hortscience. 50(3): 358-362.
- Maharaj K., T. Indalsingh, D. Ramnath and A. Cumberbatch (2003). ‘High density planting of cacao: the Trinidad and Tobago experience.’ In The Proceedings of the International Workshop on Cocoa Breeding for Improved Production Systems, edited by F. Bekele, M. J. End and A. B. Eskes, 171-181. October 19-21, 2003, Accra, Ghana.
- Mooleedhar V. and B. Lauckner (1990). [‘Effects of spacing on yield in improved clones of Theobroma cacao L.’ Tropical Agriculture (Trinidad) 67(4): 376-378.
- Shripat C. and I. Bekele (1996). ‘Yield response of improved cultivars of cocoa (Theobroma cacao L.) to spacing, pruning and fertilizer’. In Proceedings of the 12th International Cocoa Research Conference. November 18-22, 1996, Salvador, Brasil. Cocoa Producers Alliance, London, United Kingdom.