Improving field establishment of cacao (Theobroma cacao) through mulching, irrigation and shading

Abstract

Establishment of young cacao trees in West Africa can be severely impeded by the onset of the dry season. To address this issue, a field experiment was conducted in Ghana to examine whether different mulch treatments and irrigation applied during the dry season combined with overhead shade could improve survival, early growth and yield of cacao. The mulch treatments used were polyethylene film and coffee husks placed around the young plants. Irrigation was used as a positive control, and no mulching or irrigation was a negative control. Three shade regimes were provided through different arrangements of Gliricidia sepium and plantains. Four different cacao clones were used in the study in a replicated split-plot design. Early growth of cacao was stimulated under the irrigation and plastic mulch treatments. Higher rates of photosynthesis during the dry season appeared to underlie these increases. Significantly higher early yields were also observed under the irrigation and coffee mulch treatments compared with the control. Plant survival varied significantly between treatments; irrigation was associated with the highest plant survival (94%), followed by the plastic mulch treatment (91%), coffee husk (82%) and the control (70%). There was also an increase in survival when more intense shading was used. Under zero mulch conditions, differences in survival were observed between clones. The clones P 30 [POS] and SCA 6 were more sensitive to drought (in terms of survival) than PA 150 and T 79/501. It is concluded that relatively simple mulching techniques or controlled irrigation in conjunction with appropriate shade management can significantly improve early establishment and cropping of cacao.

Mulching and Irrigation Practices on Cocoa Seedling Survival and Field Establishment

“…The high survival percentage observed for M1 (90.4%) under irrigation might be attributed to increased soil moisture when plants were watered than no watering treatment. This survival percentage observed was higher than those reported by Acheampong, et al [9] who studied field establishment of cocoa under irrigation, mulching plus shading regime and reported 82% survival rate of PA 150 cocoa genotype under a shade and watering treatment. Moisture availability in soil enhances nutrient uptake by crops and results in good growth and survival.…”

“…The use of irrigation increase soil moisture and provides an additional promising path towards improved establishment of plants [9]. Most irrigation experiments on cocoa focused on yields than field establishment, but seedling survival leading to optimum population density is fundamental to obtaining maximum yield of crops.…”

Effects of Film Mulching on Plant Growth and Nutrients in Artificial Soil: A Case Study on High Altitude Slopes

“…On the other hand, the existence of film also acts as a mechanical barrier, resulting in difficulties in the emergence of plants and reducing seedling survival rate [46]. Previous studies have shown that film mulching can promote seed germination and seedling development [47,48]. This indicates that the positive effects of soil temperature and moisture on plant emergence in the mulching area are greater than any adverse effects of mechanical impedance.…”

Challenges to Cocoa Production in the Face of Climate Change and the Spread of Pests and Diseases

“…Climate change will modify cultivation area characteristics and conditions for many crops and Theobroma cacao requirements, such as daily water needs [25], a high level of relative humidity, and the absence of wind [26,27], may not be met in several currently cultivated regions, such as West Africa [28]. Climate change, especially through water availability, CO 2 elevation, and highest elevation temperature, will induce important changes in terms of tree functioning and consequently phenology [29] and physiological traits such as water use efficiency, gaseous exchange, carbohydrate metabolism, and the translocation of assimilates and nutrients [30]. Several recent studies reviewed by Lahive et al (2019) [27] show evidence of changes and interactions in cocoa tree behavior, linking genotypes, physiological traits, and climatic parameters.…”