Years ago when Lord Manjushree glided down from the Tibetan Plateau to the emerald lake of Kathmandu he saw a lotus with a thousand petals near the shore. With one mighty swipe of his sword, he cut the hill at Chobar in half, draining away the water. What emerged initially must have been a muddy and smelly swamp, but in time it became the rich and fertile valley.

The ancestors of Krishna Awale and his wife Bhinmaya have cultivated bountiful harvests over the centuries on this rich land. They believe in the Manjushree legend. Krishna is now 65 and Bhinmaya 55, and their treasure trove of knowledge about the seasons, the soil, cropping, transplanting, harvesting was passed down from one generation of Awales to the next. Nothing is written down, there are no charts and tables. But Krishna and Bhinmaya don't need notes, the wisdom of the ages is all stored in their heads. But the trouble is that since none of their children want to be fulltime farmers, it looks like the knowledge will fade away when
Krishna and Bhinmaya stop farming.

This week, Krishna and Bhinmaya are on the outskirts of Patan transplanting taichin rice on a small strip of land surrounded by concrete buildings. It is not just the knowledge that is threatened, Manjushree's legacy-the land-is also in danger of being lost. Krishna is at the far end of the field, his back bent as he hacks away at the soggy soil with a kodalo, Bhinmaya sorts out the rice seedlings in bundles so they can be planted. The sun and humidity are fierce, and Krishna takes a break, sweat streaming down his creased face. He doesn't like the look of the sky, the sun has a halo around it and the sky is deep blue. It isn't supposed to be like this on 15 Asar, the official rice planting day. "Today the naagas are not happy. They're not letting out any rain," says Krishna pouring water into his mouth from a bronze karuwa.

When Manjushree let the waters out, the creatures who suffered the most were the holy naaga that lived in the lake. These were powerful serpents, and their wrath worried Manjushree and the other gods in heaven. Manjushree, always accommodating, made smaller lakes downstream for naagas to stay. But that put the naagas at the mercy of garudas. The winged garudas are always trying to eat the aquatic naagas, and the naagas are always trying not to be eaten. This is a perennial struggle, and it is most intense during the monsoon. When they fight, it determines how much rain falls. If the garudas manage to snatch a naaga in their talons the heavens will open up with rain. "Today, the naagas have the upper hand," explains Krishna.

A little hard of hearing, Krishna is well known among his friends and neighbours in Patan's inner city for his weather forecasting ability. He doesn't need a degree in meteorology to tell instinctively from the smell of moisture in the air, the movement of the clouds, the "feel" in the morning air whether it will rain, and how much. Krishna uses sign language and expressive grunts to communicate with his wife who translates for us: "You can tell from the cool breeze from the east it will bring sudden rain. When there is a bright sun and the ground gets very warm like now, then there will be afternoon rain, and the gods suck water from the ground with their rainbows to replenish the clouds in the eastern sky."

Krishna never went to school, and no school could ever teach him what he knows. Born to a family of farmers and brick layers, Krishna was the youngest of three brothers who were all orphaned when they were young. Being the youngest, Krishna felt the loss of his parents the most, he became a street kid sleeping in patis and getting by running errands for the sahus. At 13, Krishna was sent off to far western Nepal to work in the farm of a Rana zamindar in Kailali. He returned to learn to drive a lorry when there were only four lorries in the whole of Kathmandu Valley. "These days there are so many buses and trucks and hondas," he laughs. Being a lorry driver in those days must have been like being an airline pilot today-people looked at the handsome young man Krishna with awe.

Krishna's rugged good looks haven't left him, and my Patan Newari women interpreters attested to it. Krishna's muscles glisten in the sun as he toils in the paddy field, he is lean and agile. Krishna is Bhinmaya's second husband, and the two have lived and farmed together for 35 years. Bhinmaya is proud of her husband, but acknowledges that he has a weakness for aila after which he can be a bit of a bully. Krishna is unrepentant, and signals with his fingers: "The body needs to rest after a day's work. A little aila is good for health." It was Bhinmaya who worked with her husband to turn him away from drink, so he would be healthy enough to work to feed and bring up their four children.

Krishna's oldest son now crafts bronze images of the gods through the lost-wax process, and saves enough to help his parents, repairing their house and even helping get his sister married.

"He cycles down here sometimes to bring us food and helps carry back the harvested rice and grains. And he's never shouted at me even once," says Bhinmaya.

Krishna's liking for the taichin rice is very strong, he says this is unquestionably the best suited for Kathmandu valley soil and climate. "A taichin meal is filling, and you can make a good chiura and jaad from it," he says. It doesn't need much to get Krishna into talking about drinking. All you have to ask is about the soil, rain and the taste of different traditional food and drinks. And gods.

Krishna and Bhinmaya are both devotees of Karunamaya (Red Machindranath), the Sun and the Moon. "Karunamaya is the feeder of all," he says, pointing at a ring rainbow around the sun. "The gods are having a meeting up there. They want to know why Karunamaya always arrives late." According to the myth, the god of compassion first feeds all the sentient beings, and is therefore always late for those heavenly meetings. "Without sun, the world cannot survive. I like to watch the sun god riding away in his chariot." Bhinmaya prefers the moon god's healing qualities and believes her soothing light helps the rice seedlings to grow tight and tall.

Krishna's extraordinary skills and understanding of nature, the sky, the soil and crops are in danger of vanishing with his generation. Wisdom amassed almost from the time of Manjushree will soon be gone. This loss, multiplied with tens of thousands of other Krishnas and Bhinmayas all over Nepal, will be incalculable. This is their intellectual property, and our heritage. And we have to save it.