On the second day of the United Nations Earth Summit in Johannesburg, South Africa, delegates discussed the importance of agriculture as a means to help reduce world hunger by 2015.

The United Nations estimates about 1.2 billion people worldwide live in poverty. And the UN Food and Agriculture Organization predicts the world population will rise to eight billion in 2030, further straining food resources. Pedro Sanchez, of the University of California, called on governments to concentrate on improving agriculture.

"There is no point having healthy children if they are going to die of malnutrition and also, nobody can be an environmentalist with an empty stomach, so agriculture is inextricably linked with water, energy, health, and bio-diversity."

Many rural areas have low agricultural productivity because of over-use of farmland which triggers erosion and desertification. Global warming also affects its productivity by producing unexpected climate changes with storms, droughts, and floods.

Also Tuesday, a group of members of the European Parliament and delegates visited Alexandra, one of the poorest neighborhoods in South Africa. European Parliament member Gill Evans talked about her impressions.

"There is real abject poverty here, it's been quite shocking for all of us to see just how bad the conditions are and although we have read and heard about it for many years but to see it first hand is quite a sobering experience."

In the meantime, members of non-governmental organizations said summit organizers excluded them by restricting their access to the convention center. NGO delegates said they had more requirements placed on them at the last minute.

"We are being denied our place, to be able to have our voice heard."

Campaigners said the restrictions have led to the silencing of the very people the summit is supposed to help.