BIOMASS AND NUTRIENT ACCUMULATION OF AN EARLY SUCCESSIONAL SHRUB SPECIES (Zizyphus oenoplia) IN AN UPROOTED RUBBER FIELD AT KAMBURUPITIYA

Abstract

Restoration of degraded ecosystems has become a matter of great concern. Earlysuccessional species playa key roll in the process of restoration. Therefore here astudy was undertaken to assess the accumulation and partitioning of biomass andnutrient in widely occurring early successional shrub species, namely Zizyphusoenoplia (Eraminiya) of varying ages (i.e. 4, 6 and 8 years). The experiment wasconducted at the faculty of Agriculture, University of Ruhuna, Mupalana,Karnburupitiya, during March-August, 2000. Here, four plots were selected foreach age class and four plants were sampled for each plot and their distribution ofdry matter and major nitrient (NPK) in stem, branches and leaves were measuredin each plant.

Findings clearly indicate that majority of biomass was concentrated in plant stemand as the age progressed, this proportion is increased. These results furtherindicate that the biomass allocation to the leaves was high in young ages and it isdecreasing as the age progressed. Total biomass of plant after 4, 6 and 8 yearswas 902, 2602 and 4552 g respectively.

Results also show that major nutrient content in leaves, branches and stem werehigh in early stages of the growth and decreasing as the age progressed.Percentage of N. P and K in leaves at 4 years were 2.91, 0.116 and 1.54respectively. But after 8 years N. P and K content were 2.36, 0.093 nd 1.275%respectively, show a decreasing rend of concentration of major nutrient in leaftissues. Stem and branches show the same pattern of nutrient partitioning as theplant getting matured.