text: Qualitatively weaker farm labour force is having to support urban growth of 5 to 10 per cent per annum. At the same time the pressure on marginal land contributes to the depletion of stocks of wood, soil erosion and desertification and the danger of irreversible ecological damage. 70. Population growth is, clearly, an absolutely critical element in the story, but this problem is not easy to resolve, as those Governments which have active birth control programmes are painfully aware. Rising child mortality and deepening poverty have the perverse effect of stimulating higher birth rates since it may seem rational for the individual family, if not for society as a whole, to ensure against risk by having more children, some of whom may live. Poverty is not only a consequence of the population growth problem, but its principal source. Indeed, poverty is where we should really start since poverty not only explains dangerously high birth rates, but also the way in which food shortages become famines - those who are too poor to buy food, and have few assets to sell, of necessity go hungry when their crops fail. 71. The growth of food production, at least until the recent drought, does, however, point to some positive and reassuring features in an otherwise depressing picture. One is the clear evidence of the adaptability and ingenuity of the African farmer. Where physical security, economic incentives and efficient government services have been available there has been evidence of an impressive response by small-holder farmers producing both cash crops and food. The second is the favourable population-to-land ratio. Although Africa's soils are recognized to be thin and weak on nutrients, easily damaged by too many cattle and overcropping, given adequate support for agricultural development, there is the promise of considerable improvement in production. Where the ingredients of the "green 
analysis: The text primarily discusses the challenges facing Africa, including population growth, poverty, and environmental degradation, all of which have significant impacts on the agricultural sector. The text highlights the importance of addressing poverty and the role of agriculture in supporting urban growth, while also mentioning the need for sustainable land use and conservation.