Earthworms used for vermicomposting (Karma Wangdi)

Vermicomposting (Bhutan)

Chong Boob Gi Lue Zhoni (ལྕོང་འབུཔ་ཀྱི་ལུད་བཟོ་ནི།)

Description

Vermicomposting is the practice of composting organic waste products with the aid of various types of worms. These worms aid the decomposition of organic materials, including kitchen leftovers and yard trash, resulting in the production of compost that is abundant in nutrients.

Vermicomposting is where organic wastes are broken down by redworms (Eisenia fetida or Lumbricus rubellus) and other types of earthworms. The worms produce nutrient-rich castings, which are valuable natural fertilizers for plants and enhance soil health. Vermicomposting is an effective and environmentally acceptable approach to recycle organic waste and produces a valuable resource for farming and gardening (Grant, 2021).
The raw substrate is initially ground in the gizzard to create smaller particles, increasing the surface area during the vermicomposting process. Earthworm gut microorganisms and digestive enzymes continue to work on the material to create a fine granular product that is rich in healthy nutrients and microbiota (Sharma & Garg, 2017). Vermicomposting is popular in urban gardening and horticulture, where space and resource constraints are common.
It is a sustainable and effective method for managing organic waste because it combines a number of essential traits and components. Firstly, it involves the usage of particular types of earthworms, such Eisenia fetida (red wigglers), which are renowned for their capacity to ingest enormous quantities of organic material. Maintaining optimum moisture levels, typically between 60 and 80 percent, is necessary for efficient vermicomposting. Another crucial component is aeration, which encourages aerobic decomposition and reduces odour. Vermicompost bins or beds are made with sufficient drainage and ventilation systems to do this. The ideal temperature range is between 15 o to 30 o C (Adhikary, 2012). Vermicomposting's goals and functions include waste reduction, improved soil fertility, soil restoration, sustainable agriculture, and easily accessible waste management.
Vermiculture encourages eco-friendly gardening and supports sustainable agriculture methods by limiting the use of chemical fertilizers. The initial expense and time needed to set up a vermicomposting system are two significant drawbacks. Another difficulty is the requirement for constant monitoring and upkeep, including controlling moisture levels, ensuring adequate aeration, and controlling temperature conditions. Poor environmental care can result in bad smells or even the death of earthworms.

Samtse's first and only vermicomposting facility in Norbugang gewog is performing successfully. The project, which began on a couple's farm near Bhimtar in December 2013, employs earthworms to convert organic waste into high-quality compost. It is the end result of the decomposition of organic elements by earthworms. The dzongkhag's assistant agricultural officer (ADAO) spearheaded the idea of establishing the compost plant, with assistance from the national organic program. The main substrate used for vermicomposting is cow dung and banana stems. The mixture is spread out as a bed inside the compost house for the earthworms to feed. The worms break down the mixture to produce vermicompost.
Initially, a kilogram of red earthworms (Eisenia foetida) were cultivated in a nursery. In a month, the nursery produced 10 kg, which was then employed in the project. According to Dibya Gurung, the worms needed 28 days to feed on the organic wastes in the existing compost house environment. Bhutanese farmers utilize vermicompost as a nutrient-rich organic fertilizer to enhance soil fertility and improve crop yields. This promote sustainable agriculture practices and reduce dependence on chemical fertilizers, aligning with Bhutan's goal of achieving food self-sufficiency.
There are currently 12 organic fertilizer producers in the Bhutan producing various types of compost, including vermi-compost, liquid fertilizer, bio-slurry compost, chicken manure, and EM solution. However, there is no record of a dedicated vermiculture enterprise in the nation, even though worms are required to make compost organic fertilizer, according to the National Soil Services Centre (NSSC), Department of Agriculture (DoA). For instance, the country generated 8130MT of organic fertilizers, according to the NSSC's annual report for 2021–2022 (Dorji, 2022).

Location

Location: Norbugang, Samtse, Bhutan

No. of Technology sites analysed: single site

Geo-reference of selected sites
  • 89.02592, 26.93462

Spread of the Technology: applied at specific points/ concentrated on a small area

In a permanently protected area?: Nee

Date of implementation: less than 10 years ago (recently)

Type of introduction
Vermicompost
Stocks of vermicompost ready to be sold (Tshering Zangmo)

Classification of the Technology

Main purpose
  • improve production
  • reduce, prevent, restore land degradation
  • conserve ecosystem
  • protect a watershed/ downstream areas – in combination with other Technologies
  • preserve/ improve biodiversity
  • reduce risk of disasters
  • adapt to climate change/ extremes and its impacts
  • mitigate climate change and its impacts
  • create beneficial economic impact
  • create beneficial social impact
Land use

  • CroplandIs intercropping practiced? Ja
    Is crop rotation practiced? Nee

Water supply
  • rainfed
  • mixed rainfed-irrigated
  • full irrigation

Purpose related to land degradation
  • prevent land degradation
  • reduce land degradation
  • restore/ rehabilitate severely degraded land
  • adapt to land degradation
  • not applicable
Degradation addressed
  • other - Specify: Improve soil fertility management
SLM group
  • integrated soil fertility management
  • waste management/ waste water management
  • home gardens
SLM measures
  • structural measures - S8: Sanitation/ waste water structures
  • management measures - M6: Waste management (recycling, re-use or reduce)

Technical drawing

Technical specifications
The technology is located in five acres land
Author: Niki Rai

Establishment and maintenance: activities, inputs and costs

Calculation of inputs and costs
  • Costs are calculated: per Technology unit
  • Currency used for cost calculation: Ngultrum
  • Exchange rate (to USD): 1 USD = 250.0 Ngultrum
  • Average wage cost of hired labour per day: 250
Most important factors affecting the costs
Financial and availability of earthworms
Establishment activities
  1. Site selection (Timing/ frequency: winter)
  2. Collection of raw materials (Timing/ frequency: winter)
  3. construction of vermicomposting shed (Timing/ frequency: winter)
  4. construction of bricks lined beds for rearing earth worms (Timing/ frequency: winter)
  5. Construction of FYM shed (Timing/ frequency: winter)
Establishment inputs and costs
Specify input Unit Quantity Costs per Unit (Ngultrum) Total costs per input (Ngultrum) % of costs borne by land users
Labour
labor per head 7.0 250.0 1750.0 50.0
Plant material
Cow dung Kg 5000.0 2.0 10000.0
Construction material
cement bag 145.0 290.0 42050.0
Bricks piece 4000.0 7.0 28000.0
Bamboo mat roll 10.0 3500.0 35000.0
Green net roll 6.0 2200.0 13200.0
Sand truck 1.0 3500.0 3500.0
stone truck 2.0 3500.0 7000.0
CGI sheet piece 25.0 1190.0 29750.0
Total costs for establishment of the Technology 170'250.0
Total costs for establishment of the Technology in USD 681.0
Maintenance activities
  1. construction of production house (Timing/ frequency: winter)
  2. Replacement of green net (Timing/ frequency: winter)
Maintenance inputs and costs
Specify input Unit Quantity Costs per Unit (Ngultrum) Total costs per input (Ngultrum) % of costs borne by land users
Labour
labor per head 4.0 500.0 2000.0
Construction material
cement bags 8.0 290.0 2320.0
sand bolero 1.0 3000.0 3000.0
pebbles bolero 1.0 3200.0 3200.0
Green net roll 6.0 2200.0 13200.0
Total costs for maintenance of the Technology 23'720.0
Total costs for maintenance of the Technology in USD 94.88

Natural environment

Average annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Agro-climatic zone
  • humid
  • sub-humid
  • semi-arid
  • arid
Specifications on climate
Average annual rainfall in mm: 1500.0
Annual rainfall ranges from 1500 mm to 4000 mm that occurs in monsoon month
Name of the meteorological station: National center for hydrology and meteorology
Wet subtropical zone
Slope
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
Landforms
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitude
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.
Technology is applied in
  • convex situations
  • concave situations
  • not relevant
Soil depth
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil)
  • coarse/ light (sandy)
  • medium (loamy, silty)
  • fine/ heavy (clay)
Soil texture (> 20 cm below surface)
  • coarse/ light (sandy)
  • medium (loamy, silty)
  • fine/ heavy (clay)
Topsoil organic matter content
  • high (>3%)
  • medium (1-3%)
  • low (<1%)
Groundwater table
  • on surface
  • < 5 m
  • 5-50 m
  • > 50 m
Availability of surface water
  • excess
  • good
  • medium
  • poor/ none
Water quality (untreated)
  • good drinking water
  • poor drinking water (treatment required)
  • for agricultural use only (irrigation)
  • unusable
Water quality refers to:
Is salinity a problem?
  • Ja
  • Nee

Occurrence of flooding
  • Ja
  • Nee
Species diversity
  • high
  • medium
  • low
Habitat diversity
  • high
  • medium
  • low

Characteristics of land users applying the Technology

Market orientation
  • subsistence (self-supply)
  • mixed (subsistence/ commercial)
  • commercial/ market
Off-farm income
  • less than 10% of all income
  • 10-50% of all income
  • > 50% of all income
Relative level of wealth
  • very poor
  • poor
  • average
  • rich
  • very rich
Level of mechanization
  • manual work
  • animal traction
  • mechanized/ motorized
Sedentary or nomadic
  • Sedentary
  • Semi-nomadic
  • Nomadic
Individuals or groups
  • individual/ household
  • groups/ community
  • cooperative
  • employee (company, government)
Gender
  • women
  • men
Age
  • children
  • youth
  • middle-aged
  • elderly
Area used per household
  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Scale
  • small-scale
  • medium-scale
  • large-scale
Land ownership
  • state
  • company
  • communal/ village
  • group
  • individual, not titled
  • individual, titled
Land use rights
  • open access (unorganized)
  • communal (organized)
  • leased
  • individual
Water use rights
  • open access (unorganized)
  • communal (organized)
  • leased
  • individual
Access to services and infrastructure
health

poor
good
education

poor
good
technical assistance

poor
good
employment (e.g. off-farm)

poor
good
markets

poor
good
energy

poor
good
roads and transport

poor
good
drinking water and sanitation

poor
good
financial services

poor
good

Impacts

Socio-economic impacts
Crop production
decreased
increased


The use of vermicompost in crop production offers a sustainable approach to soil fertility management, plant nutrition, disease suppression, and pest control. By harnessing the benefits of vermicompost, farmers can improve agricultural productivity.

land management
hindered
simplified


They can maintain the soil fertility, improve soil structure, retain soil moisture and improve soil health with improved soil micro flora.

expenses on agricultural inputs
increased
decreased

farm income
decreased
increased


Generate more income after the establishment of vermicomposting

diversity of income sources
decreased
increased


They can use in their own farm (floriculture) and sell to others in market.

workload
increased
decreased


They need more labor for as they have increased their farm size.

Socio-cultural impacts
food security/ self-sufficiency
reduced
improved


Compared to before they are self -sufficient and improved status in the community

situation of socially and economically disadvantaged groups (gender, age, status, ehtnicity etc.)
worsened
improved


They are able to provide job opportunities for others.

Ecological impacts
soil moisture
decreased
increased


The soil they used in their flower potting made of vermicompost content soil moisture.

nutrient cycling/ recharge
decreased
increased


They can use their kitchen waste for recycling

soil organic matter/ below ground C
decreased
increased


The vermicomposting soil contains extra nutrients for gardening.

Off-site impacts

Cost-benefit analysis

Benefits compared with establishment costs
Short-term returns
very negative
very positive

Long-term returns
very negative
very positive

Benefits compared with maintenance costs
Short-term returns
very negative
very positive

Long-term returns
very negative
very positive

Initial set-up cost is expensive and would be challenging if there is no external support.

Climate change

Gradual climate change
annual temperature increase

not well at all
very well

Adoption and adaptation

Percentage of land users in the area who have adopted the Technology
  • single cases/ experimental
  • 1-10%
  • 11-50%
  • > 50%
Of all those who have adopted the Technology, how many have done so without receiving material incentives?
  • 0-10%
  • 11-50%
  • 51-90%
  • 91-100%
Number of households and/ or area covered
1
Has the Technology been modified recently to adapt to changing conditions?
  • Ja
  • Nee
To which changing conditions?
  • climatic change/ extremes
  • changing markets
  • labour availability (e.g. due to migration)
They have increased the farm size to larger scale from small scale after they got financial support from the Nation Organic Program.

Conclusions and lessons learnt

Strengths: land user's view
  • Soil fertility is enhanced and reduce in use of harmful chemicals
  • Farm income generation
  • Can do other business like floriculture
Strengths: compiler’s or other key resource person’s view
  • Ecofriendliness
  • Well recognized by other institutions
Weaknesses/ disadvantages/ risks: land user's viewhow to overcome
  • High installment cost External supports
  • Maintenance requirements Proper management
Weaknesses/ disadvantages/ risks: compiler’s or other key resource person’s viewhow to overcome
  • Long process and challenging to harvest Systematic process and skilled labor
  • Intensive care Proper sanitation

References

Compiler
  • Karma Wangdi
Editors
  • Kuenzang Nima
Reviewer
  • William Critchley
  • Rima Mekdaschi Studer
  • Joana Eichenberger
Date of documentation: Julie 22, 2023
Last update: Junie 4, 2024
Resource persons
Full description in the WOCAT database
Linked SLM data
Documentation was faciliated by
Institution Project
Key references
  • NSSC Bhutan catalogue of soil and water conservation approaches and technologies, 2012: Website
  • Organic fertilizer production manual: http://dx.doi.org/10.13140/RG.2.2.15894.83521
Links to relevant information which is available online
This work is licensed under Creative Commons Attribution-NonCommercial-ShareaAlike 4.0 International