Programmes to increase food production have concentrated where gains are likely to be easiest: among larger farmers in relatively fertile and well-watered valleys and plains. Small farmers in upland and other areas that are difficult to farm, shifting cultivators, women farmers, nomadic herders, and the rural landless have been largely ignored. Agricultural support systems tend not to take account of the circumstances of subsistence farmers and herders. Such farmers cannot afford the high cash requirements of modern agriculture (fertilizer, etc). Many are shifting cultivators who do not have clear title to the land they work, planting a variety of crops on a single plot rather than using methods which have been developed for single crops on a large plot. Herders tend to be nomadic and difficult to locate and advise on modern agricultural methods. As with subsistence farmers, they depend on traditional rights which are threatened by commercial developments, and, although their breeds are hardy they are rarely highly productive.