ASSESSMENT OF THE EFFECT OF DIFFERENT SOIL TYPES AND SOWING DEPTH ON THE GERMINATION AND GROWTH PARAMETERS OF COCOA - Theobroma cacao Linn

ABSTRACT

The success of cocoa cultivation greatly depends on various environmental factors, including soil type and sowing depth. This study aimed to investigate the effects of different soil types and sowing depths on the germination and growth parameters of Theobroma cacao. The experiment was conducted in a screen house, utilizing a randomized complete block design with three replications. Three different soil types were used: sandy, loam, and clay soil. Three sowing depths were tested: 3 cm, 5 cm and 7 cm. Fresh cocoa seeds were planted in bags containing the different soil types at different sowing depths. Growth parameters, such as seed germination percentage, seedling emergence rate, plant height, stem girth and number of leaves were measured at different intervals during the study. The results showed that cocoa seeds germinated and emerged faster in loamy soil compared to clay and sandy soil. Final germination percentage was also higher in clay soil. The loam soil demonstrated the highest germination percentage and rate, followed by clay soil, while the sandy soil exhibited the lowest values. Furthermore, the loam soil also supported superior shoot and root growth, as well as higher above-ground biomass accumulation compared to the other soil types. Cocoa seedlings grown in loamy soil had significantly higher plant height, stem girth and fresh biomass compared to those grown in clay and sandy soil. Regarding sowing depth, 3 cm yielded the highest germination percentage and rate, as well as better shoot and root growth. Shallow sowing depths resulted in good germination performance and growth, whereas deep sowing depths negatively impacted germination and delayed plant establishment. Shallow sowing depth of 3 cm resulted in the highest germination and emergence rates, while intermediate depth of 5 cm gave the best seedling growth parameters and biomass xi production. The study suggests that sowing cocoa seeds in loamy soil at a depth of 3 cm could optimize both seed germination and seedling growth.