jesus chicaisa castillo: whether we sow beans or corn, we lose a lot of our crop.the sugar cane up there has basically dried out. and the stuff back there looks a lot better than it is. reporter: we've come to the province of narino, in southern colombia. this area is in the andes, at an altitude of 2,500 meters. much of it is farmland. climate change has made the harvest increasingly unpredictable. so farmers are relying more than ever on extra help. chemical pesticides and fertilizers may keep pests away, but they also strip the soil of nutrients. the concept of environmentally sustainable farming is not yet widespread in colombia. but in the regional capital pasto, a start is being made. banks specializing in microcredits advise farmers how they can adapt to the new conditions brought about by climate change. here, microloans are not only awarded to those just starting out, but also to encourage existing farmers to change to more sustainable methods. these include in particular techniques designed to save water. and so a steady trickle can be heard in many areas