Growth of Cocoa Seedlings as Affected by Different Growth Media and Different Polybag Sizes

Abstract

A study was conducted to determine the effects of different growth media and different poly bag sizes on the growth of cocoa seedlings in the nursery. The experimental design was split plot design with three replicates. The treatments were soil (S), carbonated rice husk (CRH), cocoa pod husk (CPH), cocopeat (CP) , sawdust (SD), S+CRH, S+CPH, S+CP, S+SD, CRH+CPH, CRH+CP, CRH+SD, CPH+CP, CPH+SD, CP+SD and the three polytene bag sizes were 12.5 cm x 18.5 cm (small), 10.0 cm x 35.0 cm (medium) and 17.3 cm x 23.3 cm (large). For the media mixes, the combination by volume used was 1:1. Number of leaves, plant height, girth, leaf area and total dry matter per plant were used for determining the most suitable media and polybag size. The results showed significant differences (p<0.05) in plant height, girth, number of leaves and total dry matter between cocoa seedlings in the different growth media and poly bag sizes. The results showed that soil and carbonated rice husk media mix and soil and cocoa pod husk media mix increased significantly (p<0.05) the plant height, stem diameter, number of leaves, leaf area and total dry matter weight. The highest number of leaves (27.7) was obtained from soil and carbonated rice husk media mix, followed by soil and cocoa pod husk media mix which recorded 26.7 leaves. In all the growth parameters, the lowest values were obtained from sawdust and its media mixes. At six months, the highest total dry matter weight was recorded in S+CPH and was 13% higher than the soil only. The size of poly bag significantly (p<0.05) affected the number of leaves, plant girth, plant height, root length, root and shoot dry weight, and total dry matter weight of the cocoa seedlings. Root weight and root length were also significantly influenced by poly bag size with the 10.0 cm x 35.0 cm recording the highest root weight. The poly bag sizes, 10.0 cm x 35.0 cm and 17.3 x 23.3 cm increased significantly (p<0.05) the plant height, stem diameter, leaf area, number of leaves and dry weights of cocoa seedlings as compared to the 12.5 cm x 18.5 cm. Generally, seedlings raised in 10.0 cm x 35.0 cm polybags produced bigger and taller seedlings, longer tap root length, and had significantly higher (p<0.05) total root weight and total dry matter per seedling than those raised in 12.5 cm x 18.5 cm polybags. However, there were no significant difference between the 10.0 cm x 35.0 cm and the 17.3 cm x 23.3 cm polybag sizes. Based on the results obtained, the poly bag size 10.0 cm x 35.0 cm would be ideal for raising cocoa seedlings since it significantly (p<0.05) produced longer root length. Additionally, the size of the 10.0 cm x 35.0 cm prevented root coiling or spiraling as compared to the 17.3 cm x 23.3cm polybag size. Generally, soil and cocoa pod husk media mix increased the growth of cocoa seedlings more than any other media mix.