Abstract:
Based on availability, the amount of above ground bio-mass and the degree of use as
compost in traditional farming systems Tithonia diversifolia, Chromolaena odorata,
Mikania scandens, Lantana camara, Wedelia trilobata, Mimosa pigra and Panicum
maximum were selected for nutrient analysis, with an attempt to investigate their
potential to be utilized in preparation of cost effective, organic potting medium for
cultivation of selected vegetables and ornamental plants. According to the
preliminary surveys, Anuradhapura, Madawachchiya, Kandy, Gampaha, Kalutara
and Kurunegala areas were selected for sample collection. Leaves and immature stem
parts of the selected plants were analyzed by two samples per one location with three
replicates. The total N, P and K contents were determined by Kjeldahl,
vanadomolybdate and flame photometric methods respectively. Atomic absorption
spectrophotometry was used for quantitative analysis of Mg, Ca, Cu Zn, and Fe.
Crude fiber content was determined gravimetrically after chemical digestion and
solubilization of the materials. Results obtained were statistically analyzed using
SPSS statistics-22 software. The nutrient contents of T. diversifolia; N (3.28%), P
(0.37%), K (2.50%), Mg (0.83%), Ca (4.92%), Cu (10 mg/kg), Zn (517 mg/kg) Fe
(296 mg/kg) and M. scandens; N (3.44%), P (0.35%), K (3.30%) Mg (1.33%), Ca
(3.39%), Cu (34 mg/kg), Zn (671 mg/kg), Fe (393 mg/kg) were significantly higher
than that of other selected weeds. However, they showed significantly lower crude
fiber contents 4.85% and 3.50% respectively. Although the nutrient content in P.
maximum was significantly low N (1.27%), P (0.24%), K (1.44%) Mg (0.5%), Ca
(1.55%), Cu (9 mg/kg), (Zn 181 mg/kg), Fe (267 mg/kg) and its crude fiber content
(20.42%) was significantly higher than that of others. It can be concluded, T.
diversifolia and M. scandens as plant materials which have higher amounts of
nutrients. P.maximum which has higher content of crude fiber also can be
incorporated in preparing compost in order to improve the physical properties of the
potting medium.
