Rapid urban expansion, resource scarcity and a growing population have led to severe ecological environmental issues in Shaanxi province, said Han Jichang, general manager of Shaanxi Provincial Land Engineering Construction Group.

The issues range from worsening air pollution, high levels of sulfur compounds, nitrogen compounds and inhalable particulates in water and land pollution.

As a result, drinking water is not safe, bringing a severe water shortage. Household garbage is also surrounding the province's cities, harming the overall urban ecological system.

Han was speaking at an international academic seminar on big data and the rise of land engineering discipline held between Sept 20 and 21 in Xi'an, the capital of Shaanxi province in Northwest China.

Statistics indicate that among more than 600 cities in China more than two-thirds lack water. Meanwhile, accumulated garbage has exceeded 700 million metric tons, occupying more than 50,000 hectares. More than 200 large-and medium-sized cities are surrounded by garbage.

Refuse landfills and open dumping also cause secondary pollution.

In the city, transport congestion and waterlogging, usually known as "urban disease", can also embarrass residents.

Land pollution is elusive, accumulative, and delayed in effect. Once an environmental crisis erupts, it causes great damage to the natural environment and people's lives.

Over recent years, Shaanxi Provincial Land Engineering Construction Group has developed the core technologies of land engineering, such as organic soil restructuring, to solve the issue of urban land pollution.

In science, land engineering is the process of turning unused land into usable land or to reclaim used land, purify it for highly-efficient use, and to coordinate the relationship between people and land.

Organic reconstruction of land involves conducting studies on the earth at a certain depth, and by the technical means of displacement, combining and restructuring to provide necessary conditions for the land to be a carrier of life.

On this basis, the international community has advocated the discipline of land engineering to guide its practical application with a theoretical foundation, Han said.

According to Han, land engineering, with organic reconstruction of land as its core technology, is the foundation of ecological progress. The scientific system covers the studies of mechanics, particle demand, land-layer restructuring, biochemical demand, bio-nutrition guarantee, water resource utilization and ecological environment design. The mechanics aims to study the features of intensity, deformity and penetration of land, and analyze and calculate its bearing capacity, consolidation and compression.

The study of particle demand aims to combine natural materials, such as soil and rocks, with artificial compounds, using them in organic reconstruction of land. This helps to scientifically guide the reform of the particles and structure of the soil.

The land-layer restructuring study seeks to construct a sound profile that is suitable for crops and human living. It helps to improve the soil's environmental quality and strengthen the coordination capacity of water, fertilizer, air and heat in the soil to enhance the quality of the earth.

The study of bio-chemical demand intends to eliminate the pollutants in and radioactive substances of the earth, to reduce the accumulation of poisons and promote environmental improvement.

The study on bio-nutrition guarantee is mainly based on the results of surveys and targeted crops. It focuses on the nutrition of the original land and the external land to adjust and control the bio-nutrition of the land overall.

The study of water resource utilization aims to utilize water resources, protect the ecological environment, conduct studies on water resource utilization, and design the most appropriate drainage and irrigation systems to use water resources to their greatest extent.

The study of ecological environment design conducts research on how land engineering affects ecological security, the ecological reconstruction and biological variety protection, the living environment construction and impact on biological environment.

By means of big data, the issues of land engineering will rapidly be solved, Han said. It will help to enhance data collection, as well as integrate key elements, calculate emulation, support decision-making and display achievements.

During the practice in recent years, the land resource sector and land engineering enterprises in China have accumulated enormous stores of information to enhance the management and service level of land resources, and "they have played an important role in carrying out land engineering development", Han said.

luhongyan@chinadaily.com.cn

(China Daily 09/21/2016 page4)