Early Growth Response of Azanza garckeana (Exell & Hillc) as Influenced by Organic and Inorganic Fertilizers
Abstract
Thespesia garckeana (also known by its synonym Azanza garckeana) is a tree in the family Malvaceae, found throughout the warmer parts of Southern Africa. The use of organic and inorganic fertilizer is a way of providing adequate nutrition to growing seedlings, while improving their quality, resistance and adaptation. The study was carried out at the screen house and laboratory of the Department of Soils and Tree Nutrition of the Forestry Research Institute of Nigeria Ibadan (FRIN). The experiment was a completely randomized design (CRD), with sixteen (16) treatments and replicated 4 times. The data collected include; stem girth (mm), plant height (cm) and number of leaves at interval of 2 weeks for a period of 16 weeks, while plant dry matter were obtained at the 16th week. Data collected were subjected to statistical analysis of variance (ANOVA) using GenStat 9th Edition, while significant different means were separated using the Duncan Multiple Range Test (DMRT) at 5% probability level. The result showed that the experimental soil was loamy sand with low nutrient status, while the combination of compost and NPK 15:15:15 at ratio 1:2 (T13) in the soil showed a significantly higher mean height at the end of the study. Treatment T6 (NPK 15:15:15 at 125kgNha-1) maintained the widest stem diameter of 7.33mm among all the treatments and was significantly wider than that of T14 (NPK 15:15:15 at 33.3kgNha-1 + AC at 66.6kgNha-1) with 5.24mm stem diameter, which was the least. The dry matter yield for the plant’s stem showed a significant higher influence from treatment T13 (NPK 15:15:15 at 66.6kgNha-1 + AC at 33.3kgNha-1) with 1.84g, while treatment T6 significantly influenced root production (6.80g) compared to those of treatments T14 and T16 (0.39 and 0.12g respectively) with a combination of both organic and inorganic fertilizers. As shown in this study, a combination of NPK 15:15:15 at 66.6kgNha-1 + AC at 33.3kgNha-1 (T13) significantly increased plant height and stem dry matter yield compared to all other treatment combinations. Likewise, higher rate of inorganic fertilizer as seen in treatment T6 also significantly increased plant’s stem growth and root dry matter yield, while NPK 15:15:15 at 50 kgNha-1 + AC at 50kgNha-1 also increased plant leaves dry matter yield. Therefore, for a productive early growth response of Azanza garckeana, the use of the combinations of NPK 15:15:15 and Aleshinloye compost is recommended.
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