Evaluation of Seedlings of Three Woody Species under Four Soil Moisture Capacities

Aims: To evaluate the growth performance, their rates of transpiration and water-use efficiencies under different moisture levels.
Study Design: A randomised complete design of three tree species, four treatments and three replicates.
Place and Duration of Study: Screen house of the University of Buea from January to June 2012.
Methodology: 144 uniform seedlings of Markhmia tomentosa, Funtumia africana and Prunus africana were treated to four soil moisture capacities (12.5, 25, 50 and 100%) determined gravimetrically and water supplied to the seedlings three times per week after pre-transplanting. The collar diameter, height and number of leaves were measured non-destructively every fortnight. The seedling biomass, leaf area, mass fractions, number of first order lateral roots, root/shoot ratio, specific leaf area, shoot and root lengths were determined six months after pre-transplanting. The seedlings’ rates of transpiration, evapotranspiration and water-use efficiencies were determined gravimetrically.
Results: The growth trends with respect to collar diameter, height and the number of leaves showed significant variations at P = 0.05. The effects of the soil moisture capacities on the growth performances were significantly different at P< 0.001. Markhmia tomentosa seedlings supplied with 25% soil moisture showed maximum leaf number (42) and leaf area (10712.8 cm2) while those with 50% treatment had collar diameter and root/shoot ratio of 17.8 cm and 2.8 respectively. Funtumia africana seedlings at 50% soil moisture capacity showed maximum height (88.6 cm) and total biomass (60.3g). Prunus africana seedlings had the least growth performance. Markhmia seedlings had the maximum rate of transpiration (12.69 gH2O/s/m2) and evapotranspiration (14.20 gH2O/s/m2). Funtumia seedlings gave the best water-use efficiency (176.5 ml/g). The poor performance observed in P. africana seedlings was as result of low elevation (≤ 450 above sea level).
Conclusion: Funtumia africana had the best water use efficiency while Markhmia tomentosa had the best root development. These two species would be suitable for the afforestation/reforestation of water catchment in humid areas of Cameroon.