"This reminds us of a colonial process even when there is no colonial link between the two countries involved," said Christina Plank, co-author of a report by the Transnational Institute on "land-grabbing".
With its current population of 1.36 billion predicted by the UN to rise to 1.4 billion by 2050, China is among the leading renter of overseas farmland in Africa, South America and Southeast Asia, though the XPCC deal would make Ukraine China's largest overseas farming centre.
China consumes about one-fifth of the world's food supplies, but is home to just nine per cent of the world's farmland, thanks in part to rapid industrialisation.
"As urbanisation speeds up, consumption has led to greater food demand and domestic grain prices have stayed above global prices," Ding Li, a senior researcher in agriculture at Anbound Consulting in Beijing, told the South China Morning Post. "Therefore, China has been importing more and more grain."
Apart from China, India, South Korea, the Gulf states and western European corporations began taking tracts of land, especially in Africa, after global food prices spiked in 2008.
XPCC however is making the first such major foray into continental Europe. It has a country that has the largest land area in the continent and was known as the "bread basket as the Soviet Union" but which has progressed slowly since the fall of the Iron Curtain.
"The special thing about Ukraine is that there is so much land and so much food left, so there is not a danger of shortage. They already export a lot of grain that they cannot consume on their own," said Ms Plank.
Campaigners are however concerned about major land deals pushing smaller farmers off the land, causing unemployment and blocking long-term rural development.
The Dnipropetrovsk transaction comes with considerable side benefits for the region. The Chinese firm said it would help build a motorway in the Crimea and a bridge across the Strait of Kerch to connect the Crimea with the Taman peninsula in Russia.
Cultivation methods in the area controlled by the Chinese would be modernised.
"On the one hand you can say this is good because you have these technological innovations and more efficient production, but then you have got to ask 'is it sustainable'?" said Ms Plank.