Small-scale biochar to improve subsistence farming in North Ghana

Author: Michael Shafer, Director, Warm Heart Foundation, Phrao, Chiang Mai, Thailand

Date: January 10, 2019

The project

In December 2018, Warm Heart Foundation trained thirty subsistence farmers in a village outside of Paga, Upper North Region, Ghana, to make biochar from waste millet stalks and rice straw using trenches in the ground snuffed using sheets of roofing zinc. (Paga lies in the North East corner of Ghana on the Burkina Faso border.)

Biochar Paga trench
Digging trench

If in two years these farmers are making and using biochar and subsistence crop yields have risen, the project will be replicated across the region.

The project aims to:

  1. provide the biochar needed to make soil amendment,
  2. restore degraded soil,
  3. increase subsistence crop yields,
  4. improve food security, and
  5. reduce pressures to switch from subsistence to cash crops.

Secondarily, it aims to:

  1. reduce smoke from the annual March burning of crop wastes to clear fields for planting and
  2. reduce eCO2 emissions from the burning.
Biochar Paga Village Meeting
Village meeting
Biochar Paga smothering trench
Smothering with zinc and dirt

The training included an overview of local agricultural, soil and economic issues, as well as an introduction to biochar and lengthy discussions with local farmers about their problems and needs.

These discussions, necessary to win farmer agreement to participate, permitted the team to conduct field demonstrations of how to make biochar from crop waste using a trench, how to mix and use biochar-manure soil amendment and how to make and use biochar enhanced compost.

Biochar Paga trench burn
Starting up the trench burn

Farmers also wanted to discuss how to organize a microenterprise for young men to make biochar and biochar-based products for the entire community. They hoped to create jobs for young man that would keep them in the community and allow most farmers to continue working as day laborers on cash cropping farms.

Importantly, biochar was not new to this village. (In fact, it is well known throughout the savannah region of North Ghana.) Experts have studied biochar’s applicability in the region for years.

They developed programs for its use – and the villages refused to accept them. The Warm Heart team faced this problem immediately. “Been there; done that. Don’t want anything to do with biochar” farmers said.

What won the villagers over was not a dazzling presentation of biochar but the response to their objections. Instead of telling them that they did not understand biochar, the team asked them why they did not like it.

The reasons, it turned out, had nothing to do with biochar and everything to do with the way the experts told them they had to do biochar. The farmers would have been happy to use biochar, they said, but they could not use it the way the experts ordered, and the experts would not bend.

There is a lesson in this for those interested in development. The issue is not the biochar. It is not the technology. It is not the obdurate farmers. The issue is recognizing the desired outcome. Is the aim to get farmers to do it your way or to get large numbers of people to change their behavior? All too often, “experts” so discount the voices of farmers that they insist on “solutions” that locals repeatedly tell will not work. When the ‘experts continue to insist, farmers either balk or stop as soon as the ‘experts’ leave.

Here the question was “Can you get large numbers of people to stop burning crop waste and instead to convert it into biochar that they then put into their soil?”

Considerations such as when the farmers made the char and not using synthetic fertilizers did not have to become deal breakers.

Because the experts required that farmers make char instead of tending their cash crop gardens, thus eliminating their sole source of income, and switch immediately to organic production, which farmers feared would imperil their crops, the farmers refused the entire biochar package.

But were timing and going organic immediately essential or secondary considerations? Count the real cost of compromises relative to their real possible benefits. Would the farmers of Paga have been worse off with biochar made at a different time of year and mixed with NKP than with no biochar at all?

This is not an isolated instance of this problem. Warm Heart encounters it routinely.[1]

The background

Life in Paga alternates between two seasons, a rainy season during which farmers plant subsistence crops such as millet that are harvested after the rains stop and a dry season during which they plant cash crops such a peppers and tomatoes irrigated with water from a government dam.

In the past, subsistence farming predominated and farmers used manure, composts and mulches to support the soil. Increasingly, cash crops predominate, supported by subsidized synthetic fertilizers and dam irrigation.

Without fallows or additions of organic materials, and with the acidifying and hardening effects of synthetic fertilizers, the quality of soil has declined, subsistence crop yields have declined and food security has come to depend on cash crop earnings. Intensification of production has concentrated cash cropping and rendered many farmers day laborers or extended family workers on a small number of commercial farms.[2]

Biochar Paga
Welcome to Upper North

The choices available to improve conditions in the Upper North are few and good choices fewer still. Politically, the solution is to super subsidize synthetic fertilizers and claim that this will supercharge food crop production, reduce food imports and drive down urban food costs.

This makes great rhetoric, but poor farm policy. Not only does much of the cheap fertilizer leak across the border, but what remains goes into cash crops that pay a good return, not into low value staples for subsistence or the local food market.

Synthetics also do nothing to solve the underlying problems of subsistence crop soils, but instead aggravate them. Improving markets for cash crops only reduces food crop production, increases food and fertilizer imports and make citizens and the country more dependent. Increasing intensification of cash cropping reduces rural labor demand and provokes rural-urban migration, placing dead weight burdens on government infrastructures at a time when labor-intensive manufacturing is shrinking.

What to do

Encourage the widespread production and use of biochar made from crop waste. Biochar is not a panacea, but it is as good as it gets in this situation. Biochar made from crop waste using very low-tech equipment during the dry season is essentially costless. Where high underemployment exists, as

Biochar Paga farmers teaching farmers
Farmers teaching farmers

in North Ghana, it also has few opportunity costs. Manure collected by little boys from fields and the production of biochar soil amendment, too, are effectively costless. Using biochar soil amendment is costless.

Biochar Paga ready to plant
Ready to plant

A farmer planting with a sharpened stick carries two bags around his/her neck, one containing seeds, one biochar mix.

(S)he makes the hole, drops in a handful of the biochar mix, brushes in a bit of dirt, drops in two seeds and pushes in the remaining dirt.

The seeds grow directly into the soil amendment, which increases yields.

Biochar Paga 100% germination
100% germination

Over several years, biochar builds up in the soil as each dose remains and the farmer plants with a new dose in a slightly different location each year. Beginning with the first dose, soil restoration begins. The soil becomes more porous, it retains more water, its pH rises (usually from 4 or 4.5) and soil life returns.

How to make low-cost biochar from crop waste

In the developed world, biochar is rocket science; in the developing world, biochar is a hole in the ground.

Actually, the easiest, cheapest way for a poor farmer to make biochar from crop waste is to dig a short trench in his/her field, pyrolyze his/her hay, stalks or straw in it and smother the fire with an old piece of roofing metal.

The system is inelegant, but it makes quite good char quite efficiently. It does not smoke and seems to emit little ammonia, methane or NOx. The roofing metal is ubiquitous in the developing world and although smothering can take up to five hours, the system requires no water, which few developing world farmers have available in their fields.

If farmers have a pile of hay, stalk or straw (for example, after threshing), they can dig as many trenches as they have sheets of roofing metal to cover. They will need them because with a ready supply of feedstock, they can fill a trench in ten to fifteen minutes with about five kilograms of biochar.

Conveniently, the char does not require drying or grinding, and is located in the field ready for use.

The result

The bottom line is simple: the farm family begins to eat more and has more risk protection in bad years – at no extra cost. Ideally, the family is, therefore, healthier and more productive, which may save money from reduced lost labor time to illness, health care costs and may result in higher income from more work off the farm.

Secondarily, to the extent that large numbers of farm families in a given area begin to char crop wastes, PM2.5 emissions during the March “burning season” will be reduced, improving public health, and eCO2 emissions will be lowered, reducing climate impact. The heavy use of char as soil amendment will also sequester large amounts CO2, reducing atmospheric carbon levels.

Why Warm Heart likes this solution

Warm Heart likes this solution for reasons that go beyond its immediate success. What Warm Heart appreciates is that this solution requires no outside intervention once it is set in motion. Once farmers undertake this program, they can teach their family and friends. They do not require outside consultants, international organizations or government agents.

The program does not depend on subsidies or other market distortions controlled by others. The production and use of super small-scale, low-tech biochar can be entirely local and can grow by imitation, not intervention.

This minimalist vision does not take account of the many grand visions that circulate about global solutions to rural poverty and food security. It is surely true that major advances are being made to connect the biotechnology, internet and telecommunications revolutions to the problems of development.

But the need is now and none of these is ready for the deep rural hinterland. No one who walks out into the bush in Africa or Asia will see any of these advances lifting the life opportunities of people. Right now, today, and for what Warm Heart believes is the foreseeable future, self-help solutions are essential.


[1] A sad example recently encountered in North Thailand involves a village used as a demonstration of a “post-corn” future. The village eliminated corn and accepted the experts’ recommendations for alternative crops. When villagers expressed concerns that the new tree crops would take years to yield and required considerable water – which the village lacked three months a year – the experts paid no attention. A year later, the village was a wasteland. All the new plantings were dead and the village was deeply in debt. The experts had gone home.

[2] Paga is exceptional in this. The government has promised “One Village, One Dam,” but the program is far behind schedule. Most villages in the North today depend exclusively on subsistence cropping supplemented by small-scale cattle raising.