The need for simple, cheap, yet effective solutions to many challenges facing agriculture in poor countries remains crucial. This has a particular urgency in Africa. In the face of all its challenges, techniques that require minimum or zero inputs are increasingly emerging as the best option for Africa's small-scale farmer.
Leguminous trees bring more milk
Incorporating fodder trees (trees that are highly nutritious, easy to grow, and improve soil fertility) in farms under agroforestry has seen dairy farmers boost milk production and household income. Such fodder trees as trichandria, tree lucane, Sesbania sesban, and sawyer lupin are leguminous, which means they fix nitrogen into the soils and enrich them. The farmer will therefore not necessarily need synthetic fertiliser. This is significant especially considering that fertiliser application in Africa remains poor - at a mere 8kg/ha (3.2 kg/acre) annually.
The World Agroforestry Centre (ICRAF) has shown that the overall impact of fodder shrubs in terms of additional net income from milk production is high. In Kenya, over the past 15 years incomes have grown from KSh 1.6 billion to KSh 2.5 billion ($19.7 million to $29.6 million). There are about 225,000 small-scale farmers in East Africa who grow fodder shrubs to feed their dairy cows, for the purposes of increasing milk production.
Mary Gichuki, trained by the ICRAF in 2006, practices this type of agriculture. She grows leguminous fodder shrubs in her small farm in Limuru of Kiambu County, some 20km west of Kenya's capital Nairobi.
"By mixing napier grass with fodder shrubs in the ratio of 1:3, I have seen a steady increase in milk production by my dairy cows from 5kg to 50kg per day per cow," says Gichuki, who is also a farmer trainer.
Gichuki now has a tree nursery from which she sells the seedlings to other farmers, besides earning more from the milk. 6,000 seedlings have already been sold this year at a cost of between 15 - 30 KSh (USD 18 - 35 cents) each.
Reaping the benefits: Conservation Agriculture for a more fertile soil
Agustine Mbugua is reaping the benefits of conservation agriculture in his single acre piece of land in the Ngata Division of Nakuru County, 170km west of Nairobi. "Not only have I stopped using fertiliser on my farm because the manure from the crop cover provides enough nutrients to the crops, but the labour costs have gone down. I used to engage two farm hands before, but I am in need of only one," he says. A five-hour labour on his farm used to cost him 200 KSh (about $2.4), per worker daily. He adds that while he used to harvest only eight, 90kg bags of maize from the single acre farm, the yield has since gone up to 20 bags.
Based on the three principles of minimum soil disturbance, crop rotation and the use of permanent soil cover, conservation agriculture has been shown to increase soil fertility. The permanent soil cover provided by crop residue decomposes to become manure and therefore enriches the soil. This cover helps retain moisture which can help grow a second crop, without over reliance on rainfall. Furthermore, crop rotation helps in reducing infection by disease, while minimum soil disturbance reduces the amount of soil carbon escaping into the atmosphere.
Combining Agroforestry and Conservation Agriculture
However, a new study conducted in Kenya, Tanzania, Zambia and Ghana released early this year by ICRAF and the Africa Conservation Tillage Network (ACT) shows a mere 5% of African farmers apply the three principles in combination. A total of 1,301 farmers in a combined 25 districts in these countries were sampled. The aim of the study was to show how the combination of conservation agriculture with agroforestry can boost farm productivity much more than either of the practices used in isolation. The use of both techniques is what is now known as conservation agriculture with trees (CAWT).
"A very small number of farmers practice conservation agriculture using the three principles," said Engineer Saidi Mukomwa, chief executive of ACT.
Scientists contend that this type of agriculture is ideal in the face of climate variability, where irregular rainfall patterns are becoming the order of the day. ACT, which has been promoting conservation agriculture, is now working with the ICRAF in this new effort. And in the wake of new concerns about a decreasing supply of phosphate in the world, the use of the two agricultural systems can only be a welcome development. Phosphate rocks are the base for manufacturing phosphate fertiliser.
"When we look at the natural resources available in the whole world, there is a high likelihood of the shortage of phosphate supply in the near future," says August Temu, deputy director of Partnership and Impact at ICRAF. He adds that there may be certain components in the inorganic fertilisers that are produced industrially that may not be available in adequate amounts, especially for farmers in the developing world which are not endowed with phosphate deposits. "These fertilizers will therefore become scarce and more expensive," he says.
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A lack of data
One of the major challenges hindering expansion of conservation agriculture with trees in Kenya has been the lack of comparative data.
"Conservation agriculture with trees needs to be backed with hard data in terms of the benefits the farmer gets in both short and long term. These are the parameters that are missing in relation to other technologies," said Engineer Jasper Nkaya, of the Ministry of Agriculture, in charge of agricultural services.
Leah Mong'ara, an extension officer with the Ministry of Agriculture, Rongai District says that another challenge lies in what she calls "crop-livestock conflict". "This is where a farmer finds it difficult to leave plants residue in the farm after harvesting when he could just as easily given it to his cows as feed," observes Mong'ara.
