Stubble and straw left over at harvest time was used as fuel for cooking stoves and food for livestock in China's vast countryside for thousands of years. But as living conditions improved, the residue largely became useless and farmers simply started burning it, causing air pollution.

Today, a company in Changzhi, Shanxi province, has designed a way to use the stubble to heat village homes, keeping emissions to a minimum, and then combining the ash with other waste to make organic fertilizer.

Shanxi Yitong Environmental Energy Technology Group finished construction of its first heating station with an environmentally friendly boiler in late 2017. It plans to put seven more stations into action this winter.

The company has also designed a production line to sort waste and convert most of the trash into organic fertilizer via fermentation. Rich in potassium, stubble ash is a key component.

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So far, almost 3,900 rural families have signed contracts with Yitong to receive heat this winter, including Guo Junlin, a farmer from Lifang village.

Guo, 49, said the stubble and straw created by his farm, which covers about 3 hectares, has been a headache for some time. He used to burn it until the environmental authorities banned the practice due to its effect on air quality.

The local government offered an alternative service in which it smashes up the straw and spreads it back on his fields. But Guo said this method attracts insects that eat newly planted seedlings.

"Corn yields, for example, can drop by 1.5 to 3 metric tons if the straw is smashed and returned to the field," he said.

Yitong made him a more attractive offer. His home was connected to the company's heating station for about 2,000 yuan ($290), more than half what it usually costs to heat his home through winter using coal.

The company also agreed to plow his fields, along with those of other participating farmers, in exchange for all his stubble and straw. Guo said it would cost him 750 to 900 yuan to plow 1 hectare.

Zhao Baoming, president of Yitong, ran a coal mine before he started the company. "My mine was easily making 200 million to 300 million yuan a year when I quit and entered the environmental protection industry," said the 56-year-old entrepreneur, who studied machine manufacturing at a technical school.

He said he has lost 20 million to 30 million yuan since starting the company and owes another 90 million yuan in bank loan repayments. He said he hopes the government will increase subsidies for companies like his, so that more solid waste can be treated properly.

Zhao estimated that his system of creating organic fertilizer recycles 90 percent of the solid waste created in the countryside.

Despite a tough start financially, Zhao said he is determined to forge ahead with the business. "Entrepreneurs want different things," he said. "Some are eager to build their companies bigger. For me, I want to follow my interests."

(China Daily 10/10/2018 page7)