Quality and Microbiological Evaluation of Phosphocompost Prepared from the Hydrothermal Pre-treated Pine Needles using Indigenous Microbial Consortium

Abstract

Pine needles are known to be the main cause of forest fires and poor soil fertility in the Shiwalik region of western Himalayas, as they are less susceptible to biodegradation. In the present investigations, an attempt has been made to prepare the bioactive phosphocompost from hydrothermally pre-treated pine needles along with other agricultural wastes. The efficient indigenous microbes (decomposers and phosphate solubilizing microorganisms) were isolated from soil, rural compost, municipal compost and mushroom spent compost. In-vitro efficacy of selected microbes to decompose the composting materials was tested singly and in combinations. The results revealed that the consortium of bacteria (DB1), actinomycetes (DA7) and fungi (DF14) was best among all tested sequential cultures. The compost was prepared in pits by enriching with rock phosphate and bone meal each @ 3%, along with efficient microbial consortium consisting of DB1 + DA7 + DF14 @ 10% by weight of composting material. The C: N ratio of prepared phosphocompost reduced from initial 56.9 to 18.1 on the 90th day of decomposition with pH 7.1. Total N, P and K content were 0.98, 2.24 and 0.81% and the amount of Fe, Cu, Zn and Mn were 25.4, 0.23, 0.42 and 0.69 mg kg-1, respectively. The total microbial count and microbial biomass was 37.3 ×105 cfu g-1 and 2357 µg g-1 of compost. The fecal coliforms were isolated at the initial days with count of 4.22×102 cfu g-1, but diminished to nil to 90th day.