Scientists invent eco-friendly plastic bags for seedlings

Scientists display a sample of seedlings wrapped in biodegradable plastics bags made from agricultural produce waste at NaCRRI in Wakiso District on March 27. Photo | Lominda Afedraru.

What you need to know:

  • The move aims to eliminate the use of non-biodegradable plastics by nursery bed operators in various parts of the country, which environmentalists say causes environmental degradation.

Agricultural scientists in Uganda have invented biodegradable plastics from agricultural waste, with a target of having nursery bed operators use them for wrapping their seedlings.

The move aims to eliminate the use of non-biodegradable plastics by nursery bed operators in various parts of the country, which environmentalists say causes environmental degradation.

The new invention was revealed by scientists from the National Agricultural Crop Resources Research Institute (NaCRRI) in Wakiso District last month while releasing their research findings about the use of agricultural waste to develop biodegradable plastics.


There is an extensive need to produce biodegradable plastics that have the ability to decompose in a short period of time hence saving the environment.

The production can be achieved using agricultural waste such as banana and cassava peels, maize waste, wheat straw and rice straw, among others.

Statistics cited by scientists from the National Agricultural Research Organisation (Naro) indicates Uganda produces about 1.4 million tonnes per year of agricultural waste from 6.5 million vegetable processing and other crops residues.

As a result, scientists at NaCRRI came up with a concept of processing biodegradable plastics, specifically for wrapping seedlings in nursery beds.

The invention is in collaboration with the University of Bangor, UK, with funding worth £80,000 (about Shs369m) from the UK government running for 10 months.

Dr Ephraim Nuwamanya, the head of the biochemistry unit at NaCRRI, who was part of the research, explained that nursery seed operators are using millions of tonnes of plastics which they later dump in farmlands, leading to soil degradation.

Dr Nuwamanya and team previously developed biodegradable plastics from cassava starch to process packaging bags but failed to penetrate the market because of the tight competition from polythene bag manufacturers.

He said focusing on nursery bed operators is a good market entry point because the aim of the innovation is to help solve the challenge of soil contamination with piles of plastics.

Advantage of biodegradable plastics

According to the scientists, biodegradable plastics form organic matter, which once planted with seedlings in the soil, will degrade after six months, thereby adding nutrients to the soil.

Once mass production kicks off in the country, the project will be an income-earning initiative to farmers because the waste material will be purchased from farmers.

The challenge of animals consuming plastics in farms will be reduced because there will be no reduced plastic littering in farmlands.

However, the product is prone to damage by insects such as termites.

But the scientists are processing insect repellent from the Tithonia Diversifolia plant, which will be incorporated as part of the ingredients of the bioplastics.

Nursery trials

The scientists have teamed up with Mount Elgon Tree Growing Enterprise in eastern Uganda, where they have set up trial sites to raise tree seedlings wrapped in biodegradable plastics.

The director of Mount Elgon Tree Growers Enterprise, Mr George Sikoyo, explained that his team has set up four trial sites within the outskirts of Mbale City where they have tree seedling nurseries.

Instead of potting the tree seedlings in plastic bags, they have used biodegradable plastics. At the moment, they treat the materials with insecticides to deal with their threats.

Some of the trials are on raised tables in order to avoid insect penetration. The sites are acting as demonstration sites where farmers growing vegetables and tree seedlings come to learn. Many of them have appreciated the technology.

Dr Nuwamanya and team said they intend to formalise intellectual property issues with Uganda Bureau of Standards in order to roll out the technology.

However the team is calling upon the private sector to come on board and take up the technology for commercialisation because the product is environmentally friendly.

How it was made

While developing the product, the team collects agricultural waste from plants, including cassava, maize, bananas and sorghum, among others, from farmer fields.

The materials are then left to dry and crushed into powder form before being mixed with water and sodium chloride. The solution is then heated, thereby producing a paste.

The paste is then passed through a machine called thinner to make a paper-like lining. It is then put in an oven to dry.

This is later put in a silk gel and dried once again in order to come up with a bioplastic product.

The production was performed at Bangor University in the UK, who have the required machinary for processing the product.

They processed 90 metres of the biodegradable plastic sheets, which were then shipped to Uganda.