in the far north of the country near the town of mpika, the rains have become less dependable. [conversation in foreign language] >> [speaking foreign language] >> traditionally, farmers here cut down patches to trees, planted maize for a few years until the soil was depleted, then moved along to the next patch. slash-and-burn agriculture like this is very difficult labor, provides only a bare subsistence level of nourishment, and exposes these farmers to the variability of climate change... >> they are a soil-fertility plant. >> but now there is hope. an agricultural revolution is happening throughout the region led by countries like zambia, which has now adopted a sustainable farming system on a national level that reduces the cost of agricultural supplies and increases food security, allowing farmers to grow crops even when the rains are variable. called conservation agriculture, more than 300,000 farmers adopted this new system since the project started in 1999. it is driven by remarkable collaboration between farmers, the ministry of agriculture, and the conservation farmi