Approximately 65 percent of Africa's population depends on subsistence agriculture. Subsistence agriculture, or small-scale agriculture, is when a family only grows enough to feed itself. Since there isn't much left for trade, the surplus is usually stored to last the whole family until the next harvest. Traditionally, Africans from savanna regions and tropical forest areas have practiced a cultivation method known as itinerant cultivation.
Farmers clear trees and shrubs from a small plot of land, burn vegetation to enrich the soil with nutrients, and then plant crops. After two or three years of use, the soil is exhausted and the plot is fallow for between 4 and 20 years until natural processes restore soil fertility. Meanwhile, farmers move on to clear and plant another plot of land and, in this way, prevent soil erosion. Farming households in this system can achieve significant improvements in agricultural productivity and in their economic and nutritional status by modifying the management of soil, crops and livestock.
Significant increases are expected to come from increased production in heavy lowland soils, in subhumid and sub-humid tropics and in irrigated land in various agricultural systems, although most production in sub-Saharan Africa will continue to come from rain-fed agriculture. By 2030, knowledge-intensive agriculture will be the norm in high-potential agricultural systems in the region, as prevails today in OECD countries. The equal access of women farmers to these facilities and services is imperative for the future development of agricultural systems in the region. Differences in wealth are partly explained by differences in non-agricultural incomes and their reinvestment in agricultural or commercial enterprises, not by differences in agricultural incomes.
The main trends are the decline in the size of farms, the decline in soil fertility and the increase in poverty and hunger. Conservation agriculture is widely practiced in Brazil through its spontaneous adoption and adaptation to adapt to different contexts and agricultural systems. Mechanized agricultural machinery, such as tractors and harvesting machines, is generally only found on large commercial farms that produce cash crops for export. Despite Africa's significant land area and the favourable average size of farms compared to several other regions, there are areas where, for historical reasons or because of demographic pressure, the size of small farms is a limitation of production.
The area is limited by agricultural systems based on trees and forests on the south side, which is more humid, and by the system of mixed grain and root cultivation on the north side, which is drier. Not only does it improve and, especially, stabilize yields in risky environments, but it also reduces production costs, including the costs of agricultural labor and agricultural energy, due to the reduction or elimination of tillage and, once established, weeding requirements. The specific problems of this agricultural system include the damage caused by birds and locusts to crops, the painstaking husking of cereals, the theft of livestock, the invasion of agriculture in coastal areas and, in southern Africa, the scarcity of land and overcrowding due to the legacy of colonial dualism. The total production of all crops in 1995-1997 was just over 250 million tons and, if current agricultural trends continue, it is expected to more than double by 2030.