Africa is home to more than 600 million mobile phone users and well over 300 million internet users.Due to rising number of internet enabled phones, farming and farmers are changing in Africa as well.The misconception of African agriculture being inefficient and unsustainable is deeply erroneous. Images of dusty ploughed fields and dying sheep and trees are misleading.But that doesn’t mean it doesn’t happen.Far from being inefficient and unsustainable, some African countries like South Africa, Tanzania, Kenya are leading the continent in conservation agriculture techniques. Conservation agriculture is based on three key principles that have guided it for decades such as minimal soil disturbance, permanent soil cover, and a diversity of plant species. It reduces tillage, retain crop residues and rotate crops.Three developments brought African farming from the tillage-based agriculture to the conservation farming revolution which is the development of herbicides. These chemicals have been refined and are now effective at targeting specific weeds with minimal environmental impact. Before herbicides, farmers’ only option for weed control was ploughing the soil to kill the weeds and to prepare a seedbed for planting.Soils had to be ploughed repeatedly because every time it rained new weeds emerged.The evolution of more effective and efficient machinery to sow through crop residue into undisturbed soil. Herbicides allow crops to be grown without ploughing, but machinery designed to sow into soft, bare, cultivated soil had to be redesigned to sow into undisturbed soil and through a mulch of residue left from the previous crop. Farmers led the innovations in machinery to make this happen.
Scientists have long argues that rotating crops is necessary for conservation agriculture. Weeds and diseases will build up in the residue and be carried from one crop to the next if the same crop is grown year after year. In addition, weeds soon become resistant to herbicides if the same herbicide is used repeatedly. By rotating the types of crop that grow, the diseases of one crop cannot build up and the types of herbicides used for the weeds can be changed each year. Legume rotation crops also make their own nitrogen which reduces the need for fertiliser. African farmers can now manage their fields down to centimetre accuracy. Precision agriculture is continuing the revolution, introducing controlled traffic, zone management and in-crop sensing to improve farming systems’ efficiency and sustainability.Controlled traffic is where farmers keep all of the machinery on the same tracks in the field, up and back instead of round and around, so that only those areas are compacted by the wheels. This reduces compaction on the field, reduces wasted spray and fertiliser due to overlaps, and makes the tractor much more fuel efficient because it is driving on harder soil. Better growth of crops in the un-compacted area compensates for the narrow tracks.Different amounts of fertiliser or other inputs can then be applied to the different zones, further increasing efficiency. Colour sensing monitors fitted to tractors can even sense how green the crop is and adjust the amount or fertiliser that is applied as the tractor is passing over the crop.It is now possible with GPS and optical sensing for farmers to deliver nutrients or herbicides exactly where they are needed in the paddock within a 2cm margin of error according to various studies.
This not only reduces costs to the farmer but reduces the impact of these chemicals and residues on the environment.However, there are still many challenges for the future.Careful management including rotating the types of herbicides that are used, destroying the seeds through collection at harvest time and growing vigorous crops that can out compete the weeds are all part of the integrated management required. Diseases that can be carried on crops residues and roots can also create problems, but selecting resistant varieties, rotating crops and judicious use of fungicides provide good control options.Crop yield in Africa has increased last 20 years under conservation agriculture systems. But there is still more scope to improve yields as there remains a considerable gap between the potential yield in experimental plots and what is being achieved on farms. Though some of this difference relates to pure economics and risk that farmers have to consider, new innovations to increase yield without higher risk are emerging.African countries are breeding new varieties to take advantage of the conservation farming techniques. New rapid real-time environment and crop sensing technology is providing quicker analysis of soil and crop conditions and allow farmers to make more timely decisions about fertiliser and other inputs in countries like Kenya, Nigeria and Ghana.As much of the change to farming with conservation agriculture is in the soil, a new focus on root-soil biology research rather than on the above-ground parts of the plant could provide new ways to improve crop performance under these new conservation systems that are being adopted in Africa.In conclusion, me thinks improved forecasts will allow African farmers to better match crops and inputs to the seasonal condition and they will be able to grow better crops with less input and reduce their financial risks as well as those to the environment.