Effects of organic soil amendments and spacing on the performance of potted nursery cocoa seedlings and survival of field transplants

The studies sought to evaluate the benefits of organic soil amendments of two types of soils at two spacing on potted nursery cocoa seedlings. Further investigations were conducted into the effects of manured nursery pots (ball of earth) on subsequent survival and growth of field transplants and seedling conditions under moisture stress in a planthouse. Four formulated topsoil media in pots, without organic manure, TOPS or with organic manure, CPH (cocoa pod husk), SD3O (sheep dropping at 30 g) and SD5O (sheep dropping at 50 g) were studied at two spacing (no spacing and 5 cm spacing). Spacing had no significant effect on all emergence and cotyledon parameters studied. Media influenced percentage seedling emergence at 10 days and number of days to 50 % emergence with the TOPS medium exhibiting a higher percentage emergence at 10 days and reaching 50 % emergence earlier than in the CPH and SD3O media There was no difference in total percentage emergence. Though there was no difference in cotyledon opening, TOPS medium significantly caused cotyledon dropping earlier than all the other media. Spacing influenced growth and dry matter parameters at four and five months from sowing and the 5 cm spacing was superior to the no spacing, except in height. Media influenced growth and dry matter parameters and the effects were across treatments. SD5O medium outperformed TOPS medium in height, stem girth, stem and shoot dry weight and seedling pan at five, two and four, four and five months respectively. Results obtained ranked the SD3O medium between the SD5O and TOPS media The CPH medium trailed in most parameters assessed and was the most seriously affected in leaf fall. Interactions were observed at five months with height and seedling span. Four (subsoil) media (SUBS, SCPH, SSD3O and SSD5O), were formulated along the same lines and rates as in the first experiment. The same spacing and experimental design were used. The 5 cm spacing delayed days to 50 % seedling emergence and similarly days to 50 % cotyledon opening. However, there was no spacing effect on percentage seedling emergence at 14 days, total percentage emergence and days to 50 % cotyledon dropping. Though emergence delayed in all media, high total percentage emergence (96.1-98.3 %) was recorded and was without differences. The SUBS medium delayed cotyledon opening but surprisingly, it significantly dropped cotyledons earlier than all the other media. Spacing affected height at four and five months and was taller in no spacing treatment. At five months stem girth was bigger in 5 cm spacing treatment than the no spacing treatments. Differences in growth occurred between the amended and unamended control (SUBS). The SUBS medium significantly prevented leaf fall and hence compared with the other media in leaf number and at five months in leaf weight. In all other parameters however, SUBS medium performed poorly than the others. SSD5O medium made significant gains over SCPH in height (4 months), stem girth (5 months) and stem weight (4 and 5 months). SSD5O medium again out-performed SSD3O in stem girth (5 months), stem dry weight (4 months) and shoot dry weight (4 months). In the field (experiment 111) the various potting media, topsoil alone or amended, effect on transplant survival was not statistically different. Occurrence of differences in some growth parameters showed a ranking in the media as SD5O > TOPS = SD3O> CPH. Under moisture stress of the subsoil formulated media in a planthouse, percentage seedlings in good conditions was significantly higher in SUBS medium than in the SSD5O and SCPH media at 10 days and all the amended subsoil at 13 days. Seedling survival after 16 days re-watering was not significant Weight of roots collected under the pots after the experiment was significantly influenced in the or4er SSD5O > SSD3O> SCPH> SUBS. The influence of manure, manure source and rate on emergence, cotyledon, growth and dry matter parameters and the lack of evidence of growth suppression by sheep manure in both nursery studies and also cocoa pod husk in subsoil study suggested the need for further evaluation for appropriate manure rates. From this work, sheep dropping at 50 g is recommended and 5 cm spacing is also recommended under optimum nutrient and appropriate conditions. LIST OF SYMBOLS AND ABBREVIATIONS 1. % Percent 2. Al Aluminium 3. ANIMAT Growth medium (with manure containing abundant animal material) 4. ANOVA Analysis of variance 5. AVRDC Growth medium (5:2:2:2 of soil: compost: sand: rice hall) 6. C Carbon 7. Ca Calcium 8. Cmol/kg Centimole per kilogramme 9. CEC Cation Exchange Capacity 10. cm Centimetre 11. cm2 Square centimetre 12. CRIG Cocoa Research Institute of Ghana 13. Cu Copper 14. CV Coefficient of Variation 15. d Day 16. et al Andothers 17. Fig Figure 18. g Gram 19. g cm-3 Gram per cubic centimetre 20. GMT Greenwich Mean Time 21. Ln Natural Logarithm 22. K Potassium 23. Kg Kilogramme 24. LSD Least Significant Difference 25. m Metre 26. m2 Square metre 27. Mg Magnesium 28. ml Millilitre 29. mm Millimetre 30. N Nitrogen 31. Na Sodium 32. No. Number 33. “N Inches North 34. ° Degree 35. °C Degree Celcius 36. P Phosphorus 37. pH Hydrogen-ion activity ( pH value= logarithm 1/CR) 38. RGR Relative Growth Rate 39. SLA Specific Leaf Area 40. TOP Growth medium (5:3:1:1 of soil: compost: sand: rice hall) 41. VAPU Growth medium (with manure mostly of fruit pulp) 42. VEFI Growth medium (with manure composed mainly of vegetable fibre) 43. “W" Inches West

Source: KNUST