Agricultural experts are lauding the steps Kenyan farmers are making in adopting a no tillage system of farming that increases yileds, but warn that failure to implement the system aggressively and quickly could lead to chronic land degradation and soil erosion that will ultimately threaten food production in the country.
The no tillage system entails planting crops into soil that has remained untilled after the harvest of the previous crop. Such cultivation has proven to have the potential, if carried out in conjunction with other appropriate agronomic practices, to improve food production, cut down labour cost in the farm by up to twenty per cent and stabilise threatened rural livelihoods.
Constant tillage threatens the health of the topsoil, which is paramount for better crop yield since it provides a housing complex for an incredibly diverse community of organisms, including billions of beneficial microbes, nitrogen-fixing fungi, nutrients and earthworms whose digestive tracts transform the fine grains of sterile rock and plant detritus into the fertile excrement that forms soil.
Scientists, borrowing from the ancient Amazonians, have come up with a way to end smallholders’ dependency on fertilizers forever, by converting waste into charcoal that doubles yields and holds carbon and minerals in soils for centuries. The newfound cheaper fertilizer option has also been hailed by local scientists and friendly to the environment since it is made of materials that are absorbed fast by the crops and friendly to the soil.
Saw dust, crop residues and chicken manure are among the waste products being used in the Biochar project in Suba district of Western Kenya, with over 300 farmers reporting a doubling in yields as a result.
Biochar is a fine grained charcoal high in organic carbon and resistant to decomposition. To produce it, biomass like chicken manure and crop residue is heated in a closed container with little or no air, resulting in charcoal.
The smoke that comes out as a by-product is trapped and converted into fuel, while the charcoal is ground into powdered form and mixed with the soil. The burning without oxygen produces a stable carbon structure that take hundreds of years to biodegrade.
Scientists have discovered that adding charcoal or other charred materials to soil is a much more effective fertilizer than any methods currently in use. Land is naturally carbon-rich, but over time and with increased agricultural use and retillage, the carbon-rich materials break down into carbon dioxide and are released into the atmosphere.
Most fertilizers available today, even composts, break down quickly and are therefore only short-term solutions to soil depletion.
However, using charcoal in the soil adds a component that easily absorbs water, holds nutrients for hundreds of years, and provides rich minerals to plants. According to Erick Kingo, a scientist from the University of Nairobi involved in the Suba Biochar project, Biochar is a simple and powerful tool to fight global warming.
The burning and natural decomposition of trees and agricultural matter contributes a large amount of carbon released to the atmosphere. Biochar on the other hand stores carbon in the soil, potentially making for a significant reduction in atmospheric carbon dioxide levels.
“Biochar will increase the fertility of problem-soils in a very noticeable, quick and long-term way. This is important for subsistence farmers, because they often cannot afford to buy fertilizers or invest in organic cultivation techniques that take a long time to establish. Biochar can be produced locally, with very low investment, and in a simple, easily understood process," said Kingo.
He further argues that Biochar has slowed down the local deforestation rate by at least 50 per cent, boosted crop yields by 100 per cent, thus improving farm incomes and alleviating poverty and hunger, and reduced fire-wood consumption by households by 50 per cent, thanks to the introduction of char-producing cooking stoves “that burn very cleanly and efficiently”.
The majority of the subsistence farmers in Suba district seeking better soil have traditionally relied on slash-and-burn agriculture, which generates greenhouse gases and decimates forests. Now that farmers are slow-smoldering their agricultural waste to produce charcoal — in effect, slash-and-char agriculture — they can fertilize existing plots instead of clearing more land. This is reducing emissions in the atmosphere, and creating a virtuous circle of environmental renewal.
Typical of the new farmers is Joshua Okaro, who has a farm in Gwassi Hills that borders Suba District, where he is raising chickens for their manure, as well as their meat. "It might look like this is just a poultry farm," says Frye. "But it's a char farm too, which has made all the difference in my farm and saving me the heavy cost of fertilizers that were choking my budget."
The making of green charcoal for fuel gained international recognition in 2002, with the development of the 'Pyro' kiln. Pioneered by a Paris-based NGO, Pro-Natura, the charcoal-making machine has been used in Senegal since late 2007, producing fuel briquettes from flakes of green charcoal mixed with a binding agent such as starch, molasses or clay.
Unlike an ordinary kiln, organic matter can be continuously fed into the French-made Pyro, and charcoal extracted, with no need for repeated cooling and reheating. Its design means it requires little external fuelling, and can produce up to five tons of charcoal a day.
Gases released by the heating process are burned in a second, post-combustion chamber, maintaining the temperature of the oxygen-free kiln at 550°C. Excess gas may also be put to other uses, such as drying the organic feedstock, or heating greenhouses.Could it really be that simple? It appears to have been for the original inhabitants of the Amazon basin. In the 16th century, Spanish explorer Francisco de Orellana wrote home describing the remarkably fertile lands he had discovered there.
In the 19th century, American and Canadian geologists uncovered the reason: bands of terra preta (dark earth), which locals continued to cultivate successfully. Research revealed that the original inhabitants of the region had added charred wood and leaves — biochar — to their lands.
Centuries later, it was still there, enriching the soil. "You couldn't help but notice it. There would be all this poor, grayish soil, and then, right next to it, a tract of black that was several meters deep," says Johannes Lehmann, a soil scientist from Brazil who, inspired by this discovery, introduced the field trials in Western Kenya.
Currently, the process of using biochar in farming is being practiced only on a small scale, but scientists now argue that it could offer a breakthrough in mitigating climate change.
Written by Bob Koigi for African Laughter
Some 20,000 smallholder farmers mostly in Western and Rift Valley province of Kenya have recorded 44 to 120 per cent increases in sorghum and millet yields on the most infertile soils in SubSaharan Africa, thanks to a new way of applying fertiliser to individual seeds.
Named precision farming, or microdosing, the process involve the application of small, affordable quantities of fertilizer with the seed at the time of planting or as a top dressing 3 to 4 weeks after the seed sprouts. This ensures that the tender crop utilises the fertilizer exhaustively, in sharp contrast to spreading fertilizer over the field, which means many crops compete for the same portion of fertilizer sprayed.
“Rather than asking how a farmer can maximize her/his yields or profits, microdosing asks how a farmer can maximize the returns to a small initial investment – that might grow over time, turning deficits into surpluses.,” said Jared Kimita a field officer actively involved in pushing the adoption of precision farming in Nakuru.
Farmers who use microdosing apply 6 gram doses of fertilizer, about a full bottle cap or a three finger pinch, in the hole where the seed is placed at the time of planting. According to the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), which has been championing the adoption, this translates to about 67 pounds of fertilizer for every 2.5 acres.
This technique, the research institution says, uses only about one-tenth of the amount typically used on wheat, and one-twentieth of the amount used on corn in the USA.
Yet the Kenyan crops are so starved of nutrients, such as phosphorous, potassium and nitrogen, that even this micro amount often doubles crop yields.
Farmers in various areas of the country where microdosing is taking shape have also adopted innovative techniques to apply microdoses of the appropriate fertiliser.
While farmers in Rift Valley use fertiliser measured out in an empty soft drink or beer bottle cap, in Central Kenya the farmers measure the fertilizer with a three-finger pinch and apply it in the same hole in which seed is sown.
Where soil is hard, farmers dig small holes before the rain starts, then fill it with manure, if available.
When rains begin, they put fertiliser and seeds in the hole and the soil provides a moist environment, encouraging root growth, and the water is captured instead of running off the hard-crusted soil.
By correcting soil deficiencies for essential nutrients with tiny doses, root systems develop and capture more water, increasing yields.
“At times like this, when the fertiliser is not forthcoming and even the available one is very expensive, this is a very economical practice. Although it may seem like we are wasting a lot with applying it to individual crops, in the long run the nutrients stay longer in the soil and allow the crop to only consume the nutrients without competition from the others, unlike the spraying method,” said Michael Nduire, who owns 5 acres of land in Rongai District of Nakuru, where he grows millet, sorghum and maize.
However, although the results have shown consistent yield increases, farmers have reported that microdosing is time consuming, laborious and difficult to ensure each plant gets the right dose of fertiliser. In an attempt to address these issues, researchers are looking at packaging the correct dose of fertilizer as a tablet that aids in application, and this is proving popular. ICRISAT one of the leading researchers is also exploring the use of seed coating as another option for further reducing the quantity of fertilizer to be used as well as the labour constraint.
According to ICRISAT, land degradation affects more than half of Africa, leading to loss of an estimated US$42 billion in income and 5 million hectares of productive land each year. The majority of farmlands produce poor yields due to poor farming techniques, nutrient deficiency and lack of water.
Land degradation is particularly acute in sub Saharan African regions where long-term overuse of soil and low, unpredictable rainfall are prime reasons for poor food production. The farmers are so poor that they take everything they can out of the soil and are not willing to invest in fertiliser because the growing season is very risky. The failure to replenish the soil fuels an unrelenting, vicious cycle. Unless nutrients are replaced, soils are depleted and yields and crop quality decline, leading to widespread hunger and under nutrition.
Unable to feed their families or afford to buy food, farmers abandon unproductive land to clear forests and plough new land, and the cycle repeats. Clearing new lands for farming is blamed for an estimated 70 per cent of the deforestation in Africa.
It is this equation that is now driving the development of microdosing.
To counter the problem of the country’s infertile soil - depleted over years by poor farming techniques and now yielding one-third of the global average - the Kenya Agricultural Research Institute is promoting a blueprint to put deficient nutrients back into soil, with warnings that it may take 30 years to fix Kenya’s sick soil.
On average, the planet is covered with little more than 3 feet of topsoil. Estimates from the Food and Agriculture Organisation have indicated that the world is losing about one per cent of its topsoil every year to erosion, mostly caused by agriculture.
With scientists insisting that true living topsoil cannot be made overnight as it grows back at a very slow rate of an inch or two over hundreds of years, farmers are being urged to adopt the no tilling method as a means of protecting the topsoil and improving food production.
Some Kenyan farmers plant seed directly into unprepared land immediately after the onset of rains, regarding it as a coping mechanism. Scientists are warning that failure to take up the no tillage system could have serious repercussions for Kenyan agriculture.
The zero tillage system has become a success story in countries where it is being practiced by farmers en masse. In Bangladesh, India and Pakistan, for example, zero tillage has reduced the demand for water in rice and wheat farming on almost a million hectares of land.
While rice and wheat are important for southern Asia's food security, yields had been stagnating and soil quality deteriorating. But a 'rice–wheat' farming system, which has a summer 'wet' crop of rice — during the monsoon season — and a winter 'dry' crop of wheat, gave scientists the leeway to introduce no tillage farming there in 2009.
The wheat seeds germinate in residual water left by the rice crop, saving up to a million litres of water per hectare. This farming technique has been widely hailed for cutting down land degradation by fifty per cent.
All scientists agree that the only problem with the zero tillage system is the over reliance on herbicides, as farmers try to clear weeds in otherwise untilled land which may affect the quality of the crop.
“You see even if you tell farmers to go weed out manually, it is almost impractical for farmers to do it all in their big pieces of land,” says Zipporah Ndeti, another scientist pushing for the adoption of no tillage in Kenya. “We are still looking for innovative and less laborious ways of doing away with weeds. We crack that and zero tillage farming will define farming in Kenya.”
Written by Bob Koigi for African Laughter
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