A project in Changtu County, Liaoning Province, has developed a series of techniques to protect its fertile black soil, which is crucial for food security and ecological sustainability. The county is a major maize and livestock producer in China, but its black soil has been threatened by erosion, intensive tillage, monocropping and insufficient organic fertilizer input.

Since 2011, Changtu County has explored technical systems such as crop straw mulching, organic fertilizer application, and big data platforms. It has also adopted comprehensive measures, such as engineering, agronomy, machinery (e.g., wide-narrow row spacing cultivation) and biology, to protect the black soil’s production capacity. At present, the county’s conservation tillage cropland has increased grain production by about 100 million jin (50,000 tonnes), and the project has improved both the agricultural and ecological benefits. It has also formed a “Changtu model” of black soil conservation, which can be replicated and promoted in other regions.

The project led by the Institute of Applied Ecology of the Chinese Academy of Sciences has used livestock manure as organic fertilizer for the soil, instead of letting it pollute the environment. This has increased the soil organic matter, improved the soil structure, and achieved resource utilization.

Changtu County is a large livestock breeding area. The county has developed circular agriculture and has integrated the resource utilization of pig manure, cattle manure and chicken manure into the black soil protection, which is a way to solve the problem of soil erosion, thinning, hardening and depletion in the black soil, and to achieve the goal of conserving and utilizing the black soil.

The county has adopted various modes of manure fermentation, such as aerobic fermentation tank, organic fertilizer factory, sewage storage pond, and black-film sealed storage. These modes can reduce the problems of odor and nutrient loss in the traditional composting. The project has also developed technologies such as solid organic fertilizer spreading and liquid organic fertilizer injection. These technologies can increase soil fertility, while preventing the pollution of livestock manure and achieving resource utilization.

Changtu County has built five demonstration sites for resource utilization of livestock manure and achieved 100% full coverage of manure treatment facilities for large-scale livestock farms. It has also reduced the chemical fertilizer application by 20% by returning 2.74 million tonnes of organic fertilizer to the fields in 2021.

A new model of smart agriculture has also been implemented in Changtu County to improve the maize production and soil quality. The model involves using straw mulching and organic fertilizer returning, selecting suitable varieties for machine harvesting, and applying big data and intelligent management. The model integrates data on soil moisture, field environment, meteorological and pest monitoring, to form a digital agricultural system. At present, Changtu County has built two smart agricultural platforms, and cultivated new agricultural business entities that operate large-scale plant protection drones.

The farmers in the county have seen the benefits of the model, such as increasing income and nourishing the soil. The county has also established a maize breeding demonstration base and promoted six excellent maize varieties that increased the yield by 50 kg per mu.

XIE Hongtu, deputy county head of Changtu County People’s Government, introduced that the model, known as the “Changtu model”, has solved the problems of soil erosion, thinning, hardening and depletion in the black soil, and provided a solution for restoring and rebuilding the black soil function and advancing modern and digital agriculture.