By David Loyn
BBC News, Punjab
The governments of many poor nations are alarmed at the rise in food prices. There are even problems in the Indian region of Punjab, where science once seemed to have found answers for a hungry world.
The first thing Satpal Singh sees when he walks out of his bedroom door in the morning is a gleaming tractor, without a speck of mud on it.
The Green Revolution made the Punjab, India's richest farmland
It is given pride of place and washed down before being put away for the night in its garage built into the middle of his house.
This is a sign of the wealth that has made this the richest farmland in India.
In Mr Singh's front yard, half a dozen cows chew contentedly on a maize-based mix, processed in his own machine in the corner.
But behind this idyll serious questions are being asked about farming practices in Punjab, which have consequences for the looming crisis in world food supplies.
Before Mr Singh's father died young of cancer in 1992, none here suspected that the technology that had brought wealth to these farmlands in the 1970s might have a downside as well.
The new strains of seed and chemical pesticides and fertilisers, certainly brought high yields.
They called it the Green Revolution.
But today the food the cows eat and the milk they produce, along with the water the cows and Mr Singh's family drink, all show high levels of pesticide residue.
As well as being a successful farmer, he works part-time as a health co-ordinator in the village.
He took me to meet a group of farmers, who all spoke of health problems and knew of deaths they believed came from the use of pesticide sprays.
The problem here, as in many other places in the world, is that the benefit of high yields from new seed types was not long-lasting, and the pests kept ahead of the pesticides.
An old man, suffering from cancer, told me that in recent years he has had to spray round the clock to keep the pests off his wheat.
Chemicals and pesticides brought high yields
The sprays all have instructions demanding that they should only be used with face masks and protective clothing.
But the farm workers here do not use protective equipment, and they spray far more than the recommended amount.
The cause of cancer is always a contentious issue, but a new study from the Punjabi University at Patiala ruled out other potential factors like age, alcohol intake and smoking, concluding that the way the sprays are used is causing cancer.
The farmers told me that they wanted the same agricultural scientists who had given them the high yields of the 1970s to come up with something else.
They know that what they are doing now is unsustainable, because they are getting lower yields despite using more spray and paying more for fertiliser because of the high oil price.
None had heard of organic farming.
In neighbouring Pakistan, the local TV news carries interviews every night from flour mills and farms, as well as a daily check on the market price of flour.
The police have intervened to stop hoarding.
Ration cards have been issued, and the World Food Programme (WFP) talks about a crisis as the number of people who do not have enough to eat has risen to 77 million, half of the population of Pakistan.
The WFP describes the food price rise as a "tsunami" affecting the poorest in the world and there are many poorer countries than Pakistan.
The political consequences are already apparent in the troubled regions of the North West Frontier, where the Taleban and al-Qaeda have significant support.
They are more easily able to recruit by saying the government is failing to make affordable food available.
And on the other side of the border on a recent trip to Afghanistan, I heard the US-led occupation squarely blamed on the streets of Kabul for the high price of food.
High oil prices, drought, over-intensive farming leading to lower yields, increased food demand in India and China and the loss of land to biofuels have all played their part in ending the long period of cheap food that the world has enjoyed for the past 30 years.
One radical solution now being talked about is direct payment of subsidies to farmers.
Until recently Malawi was dependent on food aid.
Farm workers should use protective clothing spraying crops
Back in 2002, I remember going from village to village, walking through fields where stunted maize plants had failed to grow.
Children climbed a tree to show me the tiny indigestible hard fruits which were all they had to eat.
At that time Malawi was one of a number of southern African nations at the centre of a worldwide appeal for aid.
When it introduced a voucher scheme to provide cheap fertiliser to farmers, the big donors opposed it.
Memories of corruption and belief in economic orthodoxy that allowed the market to decide prices had given subsidies a bad name.
But now international donors are starting to change their minds and back the scheme.
Malawi has turned the corner, its farms are producing food for domestic consumption as well as for export, and few go hungry.
It is a stark contrast to the picture in 2002. And maybe an example some countries currently experiencing food shortages could follow.
From Our Own Correspondent was broadcast on Saturday 26 April, 2008 at 1130 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.