Using Critical Zone Science to Enhance Soil Fertility and Improve Ecosystem Services for Peri-Urban agriculture in China
This research project focuses on sustainable intensification of agriculture in highly productive peri-urban farming areas in China. This agricultural base is essential to meet China’s increasing food production demands but is under pressure from urban pollution inputs, soil and water pollution from farming practices – particularly extensive use of mineral fertilisers and pesticides, and urbanisation. This project proposes that a substantial step change in the use of organic fertiliser, through increased recycling to land of organic wastes from agriculture and urban areas, can enhance soil processes, and hence improve yields and multiple ecosystem services.
However, organic fertilisers also carry potential risks, not only as a source of metals and industrial pollutants from wastewater, but also the occurrence of emerging contaminants such as growth hormones and antibiotics (in both animal waste and urban sewage sludge) where risks such as antibiotic microbial resistance are not fully understood, as well as altering soil biogeochemical cycles, i.e. pollutant availability.
A further challenge is the atmospheric deposition of urban pollutants, including toxic metals and nitrates, increasing the risk of food crop contamination and transport to streams and aquifers, thus polluting important sources of drinking water.
The project quantifies the benefits and risks of a substantial step-increase in organic fertiliser application as a means to reduce the use of mineral fertiliser. This will be achieved by utilising both farm (pig slurry) and urban (wastewater sludge) organic waste streams as fertiliser at high loadings to soil.
The expected outcomes
1. Maintain and increase soil fertility and food production.
2. Increase soil C storage and reduce GHG emissions via use of organic matter as fertiliser.
3. Reduce soil and water pollution from nitrate and metals mobilised by mineral fertiliser use.
4. Close resource loops by returning C,N,P from food consumption back to agricultural land.
5. Ensure the safety of organic fertilisers that improve yields.
The field study site is being developed as a Critical Zone Observatory (CZO) located in the Zhangxi catchment within Ningbo city, a pilot city of rapid urbanization in the Yangtze delta. The CZO methodology will investigate soil and water process and catchment dynamics using high-density, high-frequency multiple observing systems co-located at experimental mesocosm (m-scale) plots nested within larger areas instrumented for field (ha-scale) and whole catchment mass and flux balances. The field studies will be augmented by detailed studies of soil processes in laboratory microcosms and by mathematical modelling of soil processes at plot scale.
This project aims to deliver transformational knowledge and practice for soil and organic waste management that demonstrate solutions to China’s sustainable development ambitions to achieve food security and food safety, alleviate poverty, curb detrimental impacts of urbanisation, and maintain and improve environmental quality and natural resource protection.
The field study site is being developed as a new Critical Zone Observatory (CZO) located in the Zhangxi catchment within the greater Ningbo city conurbation, a pilot city of rapid urbanization in the Yangtze delta.
- University of Leeds
- University of Sheffield
- James Hutton Institute
- Queens University Belfast
- Nanjing University
- Chinese Academy of Science (CAS) Institute of Urban Environment
- Chinese Academy of Science (CAS) Research Centre for Eco-Environmental Sciences
- Chinese Academy of Science (CAS) Institute of Soil Science
- Scottish Government