There are increasing signs of serious food shortages in southern Sudan, putting pressure on a region which is only beginning to emerge from Africa's longest civil war.
Malnutrition is widespread in Bhar Al Gazal
The crop-forecasting early warning website, Fews, has upgraded the situation there to an "emergency".
But the World Food Programme (WFP) has received less than half of the funds it needs to deal with the crisis.
It is a huge operation.
In next year's plans, Sudan will consume 25% of the WFP's global budget.
Officials are demanding a quick response from donors to the present crisis so that they can stockpile food in the dry months to come, as the emergency bites in earnest.
Children are among the most affected by food shortages
Much of the cost of supplies goes in jet fuel.
The long-running programme of air drops from Lokichoggio airport in Northern Kenya to remote regions of Sudan continues even though the war in the south is now over.
WFP spokesman Simon Crittle said: "This is one of the poorest and most under-developed places in the world. The people here have absolutely nothing."
"If we weren't coming here, they would literally starve to death. There are no roads and the only way to get aid in here is to do it by air," Mr Crittle said.
In an effort to cut costs the WFP has become Sudan's biggest road builder, planning 2,000km (1,200 miles) of roads connecting the major towns in the south.
As well as cutting costs in delivering aid, the roads serve to energise the local economy.
When the road was cut through to Juba, now once again the capital of the south, prices in the shops there went down by 60%.
The emergency in Darfur further north has received much better funding than poorest regions of southern Sudan which border it.
"Rates show a prevalence of malnutrition comparable to what we have in Niger or in Darfur. But it seems that nobody cares, or, maybe worse, that everybody has gotten used to it," says Roger Persichino, of the French agency Action Contre la Faim.
In Bhar Al Gazal, the area with the worst malnutrition figures, I found profound pessimism about the harvest.
A grandmother, Agwak Tung Deng, said that she had been able to harvest only about 10% of her normal yield of sorghum, and what she had gathered was of poor quality.
She said that the harvest was as bad as any since 1988, when hundreds of thousands died here in the last major famine.
You did not need to be a nutrition expert to see that her family were malnourished.
Mustafa Abubakar, who has been with the WFP in Sudan for many years, said that some people were literally harvesting nothing this year.
He said that the south faced a "big crisis".
"After such a little harvest, we will have an ongoing crisis in food security in this region," Mr Abubakar said.
He calculates that the harvest will feed people on average here for about a month, when usually they depend on it for six months.
Sorghum grain is the staple diet here.
It is not an easy crop to grow, requiring good rain when it is planted in April, then a lot of work keeping weeds off as it grows, with light rains later.
Southern Sudanese rebels spent decades fighting the government
This year the rains came too late and too hard, destroying much of the little that had grown.
Even in a good year, people in Bhar Al Gazal farm at barely a subsistence level. This year, they have already fallen below that.
The late rains have caused widespread flooding, destroying houses and drowning animals as well as people.
On top of all this, the end of the war has seen a large influx of people into the south and into Bhar Al Gazal in particular, where around a third of people now beginning to come back from Khartoum and refugee camps abroad are expected to end up.
Conditions here are so bad that some of those who came home have turned back to the camps around Khartoum.
But thousands of people are flooding into Bhar Al Gazal from the fighting in Darfur as well, stretching resources even further.
I met one mother-of-three, Ayak, who looks as if she is in her mid-20s, but who does not know how old she was when she was seized by Arab slavers and taken to Darfur.
She is now back "home" in Bhar Al Gazal, living on what she can beg in the market.
Her two-year-old son Akok is severely malnourished and can barely stand up.
The tragedy of all this is that southern Sudan has huge oil reserves, which it should now be benefiting from as the war has ended.
But with the Sudanese government only just formed - nine months after the peace deal was signed - the revenue piles up in bank accounts, rather than helping to rebuild the south.
After investing in bringing the war to an end, there seems to be little urgency in the international system to invest in nation-building in the south.
It is not just food that is needed but schools, hospitals, safe water, and power.
There has been peace but no peace dividend, and hunger could add its own tensions to the mix.
Many in the south feel that the peace was imposed by the outside world against their interests.
One general told me chillingly that "war is better than a bad peace".