Options
Comparison of compost and leaf litter on shrubs and young trees of Singapore’s streetscape
Author
Sng, Hui Ting
Supervisor
Lum, Shawn K. Y.
He, Jie
Abstract
Compost and leaf litter have been shown to increase soil moisture and amend nutrient concentrations in soil. In this experiment, two types of mulch, compost and leaf litter, were applied to various shrubs planted along Choa Chu Kang Drive and Choa Chu Kang North 7. The shrubs are namely, Calliandra emarginata, Ixora ‘Super Pink’ and Duranta erecta. The control was exposed soil without any mulch. To better attribute any observed differences as the effect of mulching, the same species were grown in the National Institute of Education Greenhouse. The same three treatments (control, compost and leaf litter) were given to plants in the NIE Greenhouse after two weeks of acclimatisation.
The effect of mulching to semi-mature trees was also tested. Two-year-old plantings, Samanea saman and Pentaspadon motleyi, grown along the roadside, were randomly given one of the three treatments.
Compost or leaf litter application had little impact on soil pH and EC value. The parent materials of compost and leaf litter (leaves and dead wood) did not affect with the soil pH. Mulching also did not improve stomatal conductance. By applying compost or leaf litter to soil, the chlorophyll content in the leaves of plants increased as compared to the controls. This was observed in both shrubs and semi-mature trees. In addition, as compared to plants without any mulching, the leaf area of both shrubs and semi-mature trees increased greatly after the application of mulch, especially in plants that were mulched with leaf litter.
An increase in nitrogen, potassium and phosphorus content in leaves was only observed only in the leaves of shrubs with compost application. There were no significant changes in both the control and leaf litter mulched treatment shrubs. Also, for semi-matured trees, there were no significant differences in these elements were noted in leaves regardless of the type of treatments.
In contrast to other reports, both compost and leaf litter were not good in controlling soil moisture and leaf moisture. The moisture content did not differ from control species. Likewise, the level of micronutrients (Ca, Cu, Fe, Mg, Mn and Zn) in leaves from both compost and leaf litter treatments did not increase significantly as compared to the controls.
A possible reason might be that compost and leaf litter are organic and do not last long. Compost began to break down eight weeks after application, while leaf litter lasted slightly longer, for about ten weeks. Repeated application might be required to control soil moisture, as well as to improve micronutrient concentrations.
The effect of mulching to semi-mature trees was also tested. Two-year-old plantings, Samanea saman and Pentaspadon motleyi, grown along the roadside, were randomly given one of the three treatments.
Compost or leaf litter application had little impact on soil pH and EC value. The parent materials of compost and leaf litter (leaves and dead wood) did not affect with the soil pH. Mulching also did not improve stomatal conductance. By applying compost or leaf litter to soil, the chlorophyll content in the leaves of plants increased as compared to the controls. This was observed in both shrubs and semi-mature trees. In addition, as compared to plants without any mulching, the leaf area of both shrubs and semi-mature trees increased greatly after the application of mulch, especially in plants that were mulched with leaf litter.
An increase in nitrogen, potassium and phosphorus content in leaves was only observed only in the leaves of shrubs with compost application. There were no significant changes in both the control and leaf litter mulched treatment shrubs. Also, for semi-matured trees, there were no significant differences in these elements were noted in leaves regardless of the type of treatments.
In contrast to other reports, both compost and leaf litter were not good in controlling soil moisture and leaf moisture. The moisture content did not differ from control species. Likewise, the level of micronutrients (Ca, Cu, Fe, Mg, Mn and Zn) in leaves from both compost and leaf litter treatments did not increase significantly as compared to the controls.
A possible reason might be that compost and leaf litter are organic and do not last long. Compost began to break down eight weeks after application, while leaf litter lasted slightly longer, for about ten weeks. Repeated application might be required to control soil moisture, as well as to improve micronutrient concentrations.
Date Issued
2016
Call Number
S591.55.S55 Sng
Date Submitted
2016