Precision farming increases yields on East Africa's infertile soils

Over 20,000 smallholder farmers across East Africa are recorded 44 to 120 per cent increase 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 involves the application of small, affordable quantities of fertilizer with the seed at the time of planting or as a topdressing 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 JaredKimita a field officer actively involved in pushing the adoption of precision farmingin 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 East African 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 region where microdosing is taking shape have also adopted innovative techniques to apply microdoses of the appropriate fertiliser.

While farmers in Rift Valley area of Kenya use fertiliser measured out in an empty soft drink or beer bottle cap, in Mbeya area of Tanzania 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 provide 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 Hassan Kijo, who owns 5 acres of land in Mbeya 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 fertilizer 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.