Farming habits in East Africa and across the continent are depriving farmers of local rains, by slashing plant cover that is becoming the mainstay of the continent’s rainfall, delivering a third or more of each country’s local rain.
A 36-year long study over Africa’s 25 top watersheds found almost half of the continent’s rain is created by plants , with the share drawn from sea moisture falling steadily. But with many countries in Africa’s losing the battle with land degradation and bare-earth farming, the declining plant cover in degraded areas is reducing rain in otherwise fertile regions as well, leading to consecutive and lengthier droughts across Africa.
As a result, Southern Africa is now living through its worst drought this century, while Kenya is moving back into drought after only a brief respite from its longest drought in memory, Yet the effects of the declining plant cover are proving uneven, with the researchers from the University of Amsterdam, Ghent University, and Universidade de Vigo, finding the plant-created rain, which was falling both locally and further afield, accounted for as little as 5 per cent of rain in some areas, but as much as 68 per cent in others.
The outcome for Africa is that vegetated and poorly vegetated areas, alike, now face continuously extending droughts without the restoration of large tracts of plant cover. Yet, from 2015 to 2019, the continent is estimated to have lost 163 million hectares of plant life to land degradation. Overall, two-thirds of Africa’s productive land is progressively losing its ability to support plants.
For farmers, the habit of harvesting crops and clearing farmland to leave it bare for months waiting for rains to plant again is only increasing the shortfall in the rains – with a quarter to a third of the rainfall over the East African watersheds created by local plants.
Even small plants emit 50 grams or more of moisture a day into the air, as well as providing dead material that enriches the soil and the bacteria in it, and creating a biocrust that increases the release of rain making water vapour. The removal of all these functions is hitting local rain badly.
Yet, for farmers looking to plant local rain creators, the answer can be as simple as letting the weeds and grass grow between seasons. Farmers who do not clear or spray their shamba but lets regular grass grow instead produce up to 13.4 per cent more plant-generated water.
Farmers can also grow cash crops such as the drought-resistant mbaazi/pigeon pea and mung beans/ndengu during the ‘non-rain months’ when the usual crops like maize do not do well. The legumes add nitrogen to the soils, increasing the amount of maize in the next harvest, yield even when weeds start dying off in hot humid 38°C conditions, and survive with rainfall as low as 250 — 375 mm.
Another option is to grow fruit trees and shrubs that are built for drought. These trees release up to 3 mm of water vapour from each of their leaves daily, with scientists explaining this as a result of their deep roots pulling water up from lower soil depths
These trees such as the Moringa, Desert Date, and famously the White Cross Berry, which thrives in poor soils and under 100 milliliters of rain between June and October in East Africa also build the soil’s organic matter through their dead leaves.
Related News: Drought-Resistant Pigeon Pea: A Game-Changer for Farmers in Mbeere, Eastern Kenya