More than half of China's largest prairie area in northern Inner Mongolia Autonomous Region has become family ranches through a land contract system introduced in 1989, according to the latest government survey.

The survey by the regional agricultural and animal husbandry bureau found 66 percent of the 88 million-ha natural grassland in Inner Mongolia has become family ranches.

Some 1.6 million households have settled down after leasing the right to graze their animals under the land contract system, instead of moving freely on the grassland like what their ancestors did for centuries, according to the survey result.

This has aroused debates if the loss of nomadic traditions is good or bad for the conservation of fragile ecosystem of the grassland, which suffered desertification in recent decades.

Chaolu, a 36-year-old Mongolian herdsman, said he only had a faint memory of the nomadic life from his childhood.

His family settled down on the grassland of Taipusi Banner in the heart of Inner Mongolia in 1980s, and started to lease a 66.6-ha. lot of grassland.

It has become a routine job for Chaolu to get on his motorbike to drive his cattle back from neighboring ranches, as soon as neighbors call to alert him that his livestock have roamed onto their land.

"I can understand them. People love their own ranches like their own children, and care more about the environment," he said.

The sense of responsibility has helped locals rethink about some practice which were thought harmful for the grassland, for example, overgrazing.

Chaolu's family used to have a herd double the current number of 200 cattle and sheep.

"People for years blamed lingering droughts as the biggest cause of the degradation of the grassland. But now on reflection the overgrazing caused more harm than the weather," said Chaolu.

"The land contract system has turned herdsmen into ranch owners, making them more responsible for protecting the prairie environment," said Tuya, a researcher with the Pasture Economy Research Institute under the Inner Mongolia Academy of Social Sciences.

Previously people cared little about sustainability of the grassland because everyone could use it freely, Tuya said.

However, some experts hold the opposite opinion. Liu Runshu, a professor with the Inner Mongolia Normal University, said the degradation of the grassland gathered speed after the grassland contract system took effect.

Tuya said there were problems with the management of the grassland. For example, policies need be introduced to allow more flexible land transfers, and encourage ranch owners to make sustainable use of the leased grassland.