Status of NPK in vermicompost prepared from diverse categories of organic waste material

Abstract

Vermicomposting is the process of conversion of degradable waste material to a useful compost. Diverse categories of organic waste were collected and categorized into Kitchen, Garden and agricultural (paddy) waste on the basis of their source and origin. The waste material was decomposed using earthworms Eisenia fetida. Temperature and moisture was regulated and after approximately 2 months the dark brownish black colored compost was ready. The total weight of vermicompost harvested at the end of the study was 3 kg approximately. The present study focuses on to the preparation of vermicompost using different wastes using earthworms Eisenia fetida and analyze and compared the level of macronutrients like nitrogen, phosphorus, and potassium. Four sets of experimental tanks were used in this study. Each representing different waste material to be used as a raw material for composting. Each experimental tank contains half kilogram juvenile earthworms. In first set (A) of experiment the bedding was prepared by partially decomposed cow dung and soil. In second set (B) of experiment the bedding was of partially decomposed cow dung, soil with partially decomposed kitchen waste. The third set (C) of this bedding was of partially decomposed cow dung, soil with partially decomposed garden waste. In the fourth set (D) the bedding was of partially decomposed cow dung, soil and partially decomposed agriculture (Paddy) waste. All sets were mixed in 5:1:1 (wt/wt/wt) ratio. The pH of cow dung compost (control, A) was 8.0. pH of each compost are in range of 7.5 – 8.1. The percentage of Nitrogen (N) was found to be low in set A (Cow dung + soil) and Set D (agricultural/ paddy waste) while Nitrogen content was found to be high in Kitchen and Garden waste experimental set B and C respectively. There was no significant difference in the Phosphorus (P) content in compost A and D. While compost B and C have high phosphorus %. All compost showed significantly higher K contents than the cow dung compost (A), however the potassium (K) contents was found to be highest in compost A. When the NPK composition of all compost was compared NPK value is highest in vermicompost prepared from kitchen waste (Set B) and garden waste (Set C).