Assessment of a Cattle Manure Vermicomposting System Using Material Flow Analysis: A Case Study from Uganda

Abstract

Growth in cattle population is associated with increased manure generation whose current management in low-income countries is associated with health and environmental problems as well as low utilization rates. This trend can be reversed by promoting better manure management technologies. This study assessed vermicomposting as one of the technologies to manage organic wastes, using the case study in Uganda. A vermicomposting system using cattle manure and earthworms (Eudrilus euginea) was monitored for one year with the harvesting of products (compost, earthworm biomass) after every three months. Vermicompost samples from the beginning of the experiment and after every harvest were analyzed for the following parameters: pH, ash content, volatile and total solids, nutrients N, P, K, and C. Emissions of CO2, CH4, NH3, and N2O were also measured. Material flow analysis was used to determine the flows and retention of nutrients within the system. Results showed that total solids, ash, N, P, and K content significantly increased, while contents of volatile solids and C, as well as the pH, significantly decreased over time. Of the materials that entered the vermicomposting system, 46% went to vermicompost, 2% into earthworms, and 52% was lost to the atmosphere. Substance flow analysis showed that 30% of C went to vermicompost, 69% was emitted to the atmosphere, and 2% ended up in earthworms while 75% of N was transferred to vermicompost, 7% went to earthworms, and 18% escaped into the atmosphere. The cumulative emissions were 102 g CO2 kg−1 waste, 7.6 g CH4 kg−1 waste, and 3.943 × 10−5 g N2O kg−1 waste on a dry basis, while NH3 was not detected throughout the measurement time. Compared to other manure management methods, vermicomposting demonstrated good potential in conserving nutrients as well as reducing greenhouse gas emissions.

Comparative Performance of Organic Fertilizers in Maize (Zea mays L.) Growth, Yield, and Economic Results

“…The capacity of the digester was 6 m 3 with a loading rate of 150 kg of cattle manure and 140 L of water every three days and a retention time of 69 days. Vermicompost (V) was obtained from vermicomposting units that were constructed and maintained as specified by Jjagwe et al [24]. The units were made from wooden pallet frames from Albizia coriaria tree (local name Mugavu), each unit with a base pallet, two support pallets, and a top pallet (Figure 1) of uniform dimensions (1 m × 1 m × 0.3 m).…”

“…For T and M facilities, 720 kg of fresh manure was loaded and stored into each facility for three months from 20 December 2017 to 20 March 2018. For the S facility, 1250 kg of slurry was obtained from the digester after the retention time and stored under a shade for the same period as for T and M. Vermicomposting units also ran for three months [24]. The period of three months is suggested to be enough for stabilization of stored manure/compost [25,26].…”

“…With regard to the different manure treatment methods, vermicomposting has been reported to be the most environmentally-friendly in reducing nutrient losses and greenhouse gas (GHG) emissions to the atmosphere. For instance, vermicomposting of cattle manure was reported to retain more than 75% of the initial nitrogen after three months [24] as compared to 69% and 54% N retention from stockpiling and composting of cattle manure, respectively, for the same storage period [48]. In terms of GHG emissions, vermicomposting of cattle manure had a global warming potential (GWP) of 324 kg CO2 eq t −1 waste after three months of evaluation [24] as compared to GWP of 605 kg CO2 eq t −1 waste, 741 kg CO2 eq t −1 waste, and 605 kg CO2 eq t −1 waste from composting, stockpiling, and anaerobic digestion of cattle manure for the same evaluation period [49].…”

Unveiling the Efficiency of Psychrophillic Aporrectodea caliginosa in Deciphering the Nutrients from Dalweed and Cow Manure with Bio-Optimization of Coprolites

“…Dal Lake is situated in the heart of Srinagar city (latitude 34 • 18 N longitude 74 • 91 E) of the state of Jammu and Kashmir (J&K). Dalweed (DW), or Sustainability 2021, 13, 5338 2 of 13 Dal lake weeds, are a diverse group of aquatic weed flora comprising Nelumbo nucifera, Lemna minor, Azolla sp., Salvinia cuculata, Trapa natans, Potamogetton crispus, Potamogettonlucens, Pistia sp. Hydrilla verticillata, Ceratophyllum demersum, Myriophyllum spicatum, and Myriophyllum verticillatum [1].…”

“…Recycling of aquatic weeds can solve disposal issues [8]), and enhances their agronomic value with the building up of earthworms (biomass, hatchlings, and cocoons) [9]. Traditionally, cow manure is regarded as an important resource for sustainable rural agriculture [10,11] and a primary substrate for vermicomposting [12,13]. There has been a rapid increase in cattle farming as a pivotal source of livelihood among Himalayan farmers.…”