By Alex Kirby
BBC News Online environment correspondent
Agriculture has always been central to the European Union, and never more so than now that enlargement has happened.
Farming is changing rapidly in the new member states
The EU spends half its entire budget, £30bn ($54bn or 44bn euros), on various measures to support the continent's farmers.
But in the new member states, farming is far more important economically, providing on average five times as many jobs as it does in the original 15 nations.
So the way farm policy develops will certainly affect lives across Europe, and in the developing world as well.
Farmers in the 10 new states will in one sense be second-class EU members, because the direct income support they receive will be only a quarter of the rate paid to their counterparts in the older members.
Under the reform of the Common Agricultural Policy (CAP) subsidies will be based on the area farmed, instead of the food or crops produced.
So the many small farmers of central and eastern Europe, who will not gain much this way, are one probable group of losers.
Focus on profitable land
Inevitably, in many countries they will be forced off the land: with 21% of the working population in accession countries occupied in agriculture, against 4% in the 15 states, this will require a big expansion of urban jobs.
Payments for rural development measures, though, will be at about the same levels across the EU.
The European Environment Agency (EEA) says "two environmentally damaging trends" may become more pronounced.
Eastern Europe retains much the West has lost
It says: "One is a moderate intensification of agriculture in productive areas, involving greater use of fertilisers, pesticides and machinery to increase yields.
"The other trend is the abandonment of farming on marginal, less productive land that often hosts an abundance of wildlife."
The EEA says areas likely to be abandoned cover principally species-rich grassland that needs grazing by sheep and cattle to maintain its richness.
It thinks the CAP's rural development provisions can help, including agri-environmental schemes, aid for less-favoured areas, and help for small, semi-subsistence farms.
Landscapes at risk
The EU has committed itself to halting the loss of biodiversity by 2010. Professor Jacqueline McGlade, the EEA's executive director, said: "Current policy measures appear insufficient to prevent further decline in high nature-value farmland areas and reach the 2010 target.
"Consideration needs to be given to improving the geographical targeting of agricultural subsidies."
IUCN-The World Conservation Union is concerned that some of the money going into rural development and structural funds will encourage intensive farming and destroy traditional landscapes.
Small farmers may be squeezed out
Farmers in the accession countries with bigger holdings are likely to gain from their new status, especially if they do intensify and can meet the demands of western agri-business for dependable production of bulk crops.
The UK's Royal Society for the Protection of Birds fears the impact on farmland creatures. Zoltan Waliczky of the RSPB said: "The biggest threat facing common and rare birds alike is the extension of the CAP... to the accession countries.
"Bird surveys have shown that numbers of farmland birds have largely recovered since the collapse of the socialist regimes in eastern Europe but, with subsidies on the way, this trend is expected to reverse."
Mr Waliczky told BBC News Online: "One of the main attractions of membership for the new states is the subsidies, and my main fear is that they'll oppose CAP reform, while in fact they should be driving it."
There is also concern that the new members will be conservative on trade policy, opposing change and resisting moves to make it easier for developing countries to export their produce to the EU.