1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

No

Comments:

Mulching in agriculture helps conserve moisture, prevent water and wind erosion, control weeds, and regulate soil temperature. While it has these benefits, it also poses environmental concerns related to soil contamination and waste accumulation. Plastic mulches are a significant source of microplastic pollution in agricultural soils. The residual microplastics in the soil negatively affect soil health. Used plastic mulches are eventually burned and the burning releases greenhouse gases, contributing to climate change and global warming. Additionally, the residues left behind after burning plastic mulches can persist in the soil for extended periods thereby contaminating the soil. Though mulching helps increase crop yields, it has negative effects on the natural environment and thus the use of mulching necessitates careful consideration.

2.1 Short description of the Technology

Definition of the Technology:

Plastic mulching comprises thin plastic sheets laid out on raised soil surfaces around plants to help conserve soil moisture, prevent water and wind erosion, control weeds, and regulate soil temperature. It is used in agriculture to increase crop yields. However, there are environmental concerns about soil contamination and waste disposal.

2.2 Detailed description of the Technology

Description:

Plastic mulching is a widely used agricultural practice in Bhutan, primarily employed in the cultivation of cash crops. Farmers have adopted plastic mulching to enhance crop production and address specific agricultural challenges. It allows farmers to optimize water usage by reducing evaporation and maintaining soil moisture levels, which is crucial in regions where water resources are limited. It also helps suppress weed growth, minimizing competition for nutrients and ensuring healthier crop growth. Additionally, the regulation of soil temperature through plastic mulching can extend the growing season and improve crop quality and yields. These benefits are particularly valuable in Bhutan's mountainous terrain and varied climatic conditions.
However, the application of plastic mulching can have both direct and indirect impacts on the natural environment. Improper disposal or management of plastic mulch can lead to environmental pollution, including soil contamination and plastic waste accumulation. Therefore, sustainable practices and appropriate waste management techniques are crucial to minimize the potential negative effects on the natural environment.
Plastic mulching serves several purposes and functions in agricultural practices. One of its primary functions is moisture conservation, as it helps prevent water evaporation from the soil surface by acting as a barrier. Additionally, plastic mulch controls weeds by blocking sunlight and inhibiting weed seed germination, reducing competition for nutrients. Another important function is soil temperature regulation, as plastic mulching traps heat from the sun, raising soil temperatures in cooler climates and promoting faster plant growth. Overall, plastic mulch contributes to enhanced crop performance.
Furthermore, it helps prevent soil erosion by protecting the soil surface from wind and water erosion, thus maintaining soil structure and fertility, and creating a barrier between plants and the soil, reducing the risk of soil-borne pests and diseases affecting the crops. It can also deter certain pests by disrupting their habitat and limiting access to plants.
Plastic mulching involves the use of thin sheets or films made of polyethylene or similar materials, which come in various colours and thicknesses. Manual tools are utilized to lay the sheets evenly over the prepared soil. Before laying the plastic mulch, the soil is typically ploughed, levelled, raised, and cleared of debris to create a smooth surface. To prevent displacement by wind or other factors, the plastic mulch needs to be securely anchored to the ground. Plastic mulching can be combined with drip irrigation systems to provide water and nutrients directly to the plant roots.
Some specific advantages pointed out by the land user include the opportunity to achieve higher returns on agricultural investments. It reduces the need for manual weeding or herbicide application, saving time, labour, and resources. Additionally, it reduces the frequency of irrigation. It also extends the growing season expanding options and potential profits. There are many advantages of mulching but there are some serious disadvantages of the technology. Plastic mulching poses environmental concerns related to soil contamination and waste accumulation. Plastic mulches are a significant source of microplastic pollution in agricultural soils and these microplastics negatively affect soil health. The disposal of plastic mulches is a challenge as recycling options are limited resulting in waste accumulation on farms. These accumulated wastes are eventually burned and release greenhouse gases, contributing to climate change and global warming. Additionally, the residues left behind after burning plastic mulches can persist in the soil for extended periods thereby contaminating the soil. Also, the cost of purchasing plastic mulch can prove to be too high for farmers if the land area is huge. Though mulching helps increase crop yields, it has negative effects on the natural environment - thus the use of mulching necessitates careful consideration.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

Country:

Bhutan

Region/ State/ Province:

Sergithang, Tsirang

Specify the spread of the Technology:

• evenly spread over an area

If precise area is not known, indicate approximate area covered:

• < 0.1 km2 (10 ha)

Is/are the technology site(s) located in a permanently protected area?

No

Comments:

The land user uses plastic mulching on 1 acre of land for chili production.

Map

×

2.6 Date of implementation

Indicate year of implementation:

2018

2.7 Introduction of the Technology

• It was introduced by the gewog Agriculture Extension Officer and through exposure to social media.

3.1 Main purpose(s) of the Technology

• improve production
• create beneficial economic impact

3.2 Current land use type(s) where the Technology is applied

Land use mixed within the same land unit:

Yes

Specify mixed land use (crops/ grazing/ trees):

• Agroforestry

Cropland

• Annual cropping
• Tree and shrub cropping

Annual cropping - Specify crops:

• cereals - maize
• cereals - rice (wetland)
• root/tuber crops - potatoes
• vegetables - leafy vegetables (salads, cabbage, spinach, other)
• vegetables - melon, pumpkin, squash or gourd
• vegetables - root vegetables (carrots, onions, beet, other)

Tree and shrub cropping - Specify crops:

• avocado
• fruits, other
• mango, mangosteen, guava

Number of growing seasons per year:

• 2

Is intercropping practiced?

Yes

If yes, specify which crops are intercropped:

Vegetable crops are intercropped for self-consumption.

Is crop rotation practiced?

Yes

If yes, specify:

Vegetable crops are rotated.

Forest/ woodlands

• (Semi-)natural forests/ woodlands

Are the trees specified above deciduous or evergreen?

• mixed deciduous/ evergreen

Products and services:

• Fuelwood

3.3 Has land use changed due to the implementation of the Technology?

Has land use changed due to the implementation of the Technology?

• No (Continue with question 3.4)

3.4 Water supply

Water supply for the land on which the Technology is applied:

• mixed rainfed-irrigated

Comments:

The land users of Sergithang face water shortage problems.

3.5 SLM group to which the Technology belongs

• Weed management

3.6 SLM measures comprising the Technology

other measures

Specify:

Plastic mulching may fall under structural measures.

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

• Wt: loss of topsoil/ surface erosion

soil erosion by wind

• Et: loss of topsoil

biological degradation

• Bp: increase of pests/ diseases, loss of predators

water degradation

• Ha: aridification
• Hs: change in quantity of surface water

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• prevent land degradation
• reduce land degradation

Comments:

Plastic mulching prevents soil and water erosion and conserves soil mositure.

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

This diagram shows a cross-section of a raised bed using plastic mulching. The plants grow through the punctured holes in the plastic. The length of the bed varies from farm to farm and is 1 m wide and spaced 30 cm apart (bed-bed spacing) for easy access/movement. The bed is usually raised to 20 cm in height. The planting distance shown in the diagram is for chilies, 50-70 cm. The distances will vary according to the crop/variety.

Author:

Thinley Penjor Dorji

Date:

20/07/2023

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

• per Technology area

other/ national currency (specify):

Ngultrum

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

82.1

4.3 Establishment activities

4.4 Costs and inputs needed for establishment

4.5 Maintenance/ recurrent activities

Comments:

No maintenance work has been carried out.

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

If you are unable to break down the costs in the table above, give an estimation of the total costs of maintaining the Technology:

29823.0

Comments:

The plastic mulch is reused and hence there is no expenditure on the plastic mulches.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Higher cost of plastic mulching and hiring a power tiller.

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• not relevant

5.3 Soils

If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Moisture content-4.46%
Organic matter-5.85 %
Organic carbon-3.40%
pH-6.15
Electrical conductivity-853.00 µs/cm
Nitrogen-0.17
Phosphorus-1.92
Potassium-198.73 mg/100ml
Soil texture-Silt Clay Loam

5.4 Water availability and quality

Is water salinity a problem?

No

Is flooding of the area occurring?

No

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

5.7 Average area of land used by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• individual, titled

Land use rights:

• individual

Water use rights:

• communal (organized)

Are land use rights based on a traditional legal system?

Yes

Specify:

The land use rights in Bhutan are based on a traditional legal system guided by formal land-act rules and regulations.

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Income and costs

Socio-cultural impacts

Ecological impacts

Soil

Specify assessment of on-site impacts (measurements):

These are the on-site impacts that have been shared by the land user. The land user has reused the mulches. He is unaware of the soil contamination caused by the plastics due to residual microplastics in the soil but is well aware of the wastes that will be generated. For the lack of better waste disposal options, like many other land users of the community the land user will opt to burn the wastes.

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

Gradual climate change

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

Comments:

In the long run, the benefits will be negative, as the land user has to invest in additional costly plastic mulch. Furthermore, the existing mulching plastic is not durable.

6.5 Adoption of the Technology

• > 50%

If available, quantify (no. of households and/ or area covered):

All the land users of Sergithang have implemented the technology.

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?

• 91-100%

6.6 Adaptation

Has the Technology been modified recently to adapt to changing conditions?

No

6.7 Strengths/ advantages/ opportunities of the Technology

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

7.1 Methods/ sources of information

7.3 Links to relevant online information

Title/ description:

Vegetable cultivation Theme 3 Mulching

URL:

http://rcbajo.gov.bt/wp-content/uploads/2020/05/Veg-Theme-03-Mulching-printing.pdf