"I'm thrilled by China's support!" Chinese and African scholars "join hands" in nitrogen research

Text | "China Science News" reporter Feng Lifei

Gu Baojing (right) meets with Mahesh Pradhan in Beijing in July. Photo courtesy of the interviewee

About half of global food production comes from nitrogen fertilizers. However, nitrogen loss leads to severe air and water pollution, as well as biodiversity loss and climate change.

More than half of the United Nations Sustainable Development Goals (SDGs), adopted by the United Nations in 2015, are directly related to nitrogen use and loss, but the global distribution pattern of nitrogen is uneven.

How to manage agricultural nitrogen to promote balanced development and sustainable development among countries?

This year, Gu Baojing, a professor at Zhejiang University's School of Environment and Resources, collaborated with African scientists to answer this challenging question, with the support of the International Collaborative Research Project "Synergies for Achieving the United Nations 2030 Sustainable Development Goals through Agricultural Nitrogen Management" (China-Africa Nitrogen Cooperation Project), which is jointly supported by the National Natural Science Foundation of China (NSFC) and the United Nations Environment Programme (UNEP).

Small elements build bridges

Nitrogen is abundant in the Earth's atmosphere. It makes the sky blue and the soil fertile, and is the basis for the formation of human proteins. However, excess nitrogen in the environment can pollute land, water and air, exacerbate climate change and deplete the ozone layer.

UNEP believes that nitrogen pollution has become the focus of environmental problems and is one of the most important pollution problems facing mankind.

At the same time, nitrogen pollution is also a constraint on SDGs.

"Since the 17 SDGs were proposed in 2015, we are still far from achieving these goals, especially with regard to the methodological pathways and indicators for achieving the Sustainable Development Goals, which are still relatively limited." Gu Baojing told China Science News, "Nitrogen is a good starting point for optimizing the path to achieve SDGs. Because half of the SDGs are related to it, and the other half are indirectly related to it. ”

Food security, poverty and hunger eradication, clean water, clean energy, climate change, economic growth... Many aspects of human well-being are related to nitrogen. Gu Baojing, who has been researching nitrogen cycling for a long time, hopes to link her research with the SDGs and do something to achieve sustainable development.

His expectations were supported by the Natural Science Foundation of China. In 2022, the China-Africa Nitrogen Cooperation Project came into being, and nitrogen has become another bridge for China-Africa cooperation in science and technology. The collaboration aims to answer key questions about the relevance of the nitrogen cycle to the SDGs using a multidisciplinary approach. For example, what is the driving mechanism of the nitrogen cycle for the Sustainable Development Goals? What is the contribution of nitrogen to the global Sustainable Development Goals? How can nitrogen management achieve synergy across multiple global SDGs?

"This project is important for countries facing challenges such as hunger, poverty, environmental and climate threats, and will help provide policy support for UNEP's nitrogen management resolution and balance nitrogen use at the national scale." Gu Baojing said, "The Natural Science Foundation of China hopes to promote the mainland to make more contributions to major international environmental issues and support sustainable development, and we feel very fortunate to receive support." ”

At the recommendation of the UNEP International Partnership in Ecosystem Management (UNEP-IEMP), Dr. Mahesh Pradan, Coordinator of the International Nitrogen Management System (INMS) based in Nairobi, Kenya, and Dr. Kagli Marceau, National Agroecological Research Representative of the International Institute of Tropical Agriculture in Cameroon, became a partner of Gu Baojing.

What touched Gu Baojing was that despite the lack of funds, the African collaborators still took the initiative to provide support equivalent to 3 million yuan in terms of human and material resources, matching with the National Natural Science Foundation of China to fully support the development of the project.

"I'm very excited that China can support a project like this," Pradhan said. Chinese scientists have done a lot of work in the field of nitrogen research, and have been playing a particularly important role in international nitrogen fertilizer research, and we hope that more can be done in the balanced utilization of nitrogen through our cooperation. ”

"The African side is very willing to join in, and this is a particularly good opportunity for mutual progress." Marceau said. Thirty years ago, he received a bachelor's degree in soil chemistry and plant nutrition from Zhejiang University, and then pursued a master's degree there, and has a deep affection for China.

Based on Central Africa and looking at the world

"How to optimize nitrogen management to achieve the SDGs is at the heart of our research." Gu Baojing said.

However, nitrogen is an important part of the global ecological and biochemical cycle. How to relate it to the SDGs, which are closer to the demands of human society, and how to extend the nitrogen cycle in nature to human society is a global problem.

At the same time, there is still a lack of in-depth research on the synergistic effects of different pathways and coupling scales of the global nitrogen cycle, and it is difficult to obtain accurate nitrogen cycle data and information from various countries, which brings challenges to related research.

The collaborative team's interdisciplinary, cross-departmental academic background supports answering and solving these questions. The project brings together more than 20 researchers from three scientific research institutions at home and abroad, and the research content ranges from cold regions to tropical regions, from water, soil to atmosphere, and from macro to micro scales, building an international cooperation network covering multiple disciplines and fields.

"We can provide new tools and methods for nitrogen management and sustainable development in different regions through multidisciplinary interdisciplinary research methods such as model simulation, spatial statistics and econometric analysis, and environmental effect assessment." Gu Baojing said.

He further introduced that model simulation can elucidate the driving mechanism of the nitrogen cycle on the SDGs, spatial statistics and econometric analysis can quantify the contribution of nitrogen to the global SDGs, and environmental effect assessment can further analyze the synergy or trade-off mechanism of different SDGs in nitrogen management, providing theoretical basis and technical guidance for subsequent national decision-making. These cross-cutting combinations and their interactions are an integrated pathway to achieving the Sustainable Development Goals.

Since the start of the collaboration in early 2023, the team has been based in China and Africa, looking internationally and trying to model global nitrogen fluxes.

They reviewed a large number of data and analyzed the impact pathways of the nitrogen cycle, such as the impact of various socio-economic and environmental drivers such as fertilizers, coal burning in power plants, gasoline combustion, aquaculture waste, domestic sewage and wastewater, and modeled the global nitrogen flux in the coming decades to predict the change of nitrogen flux from 2050 to 2060 using the global nitrogen flux in 2020 as a baseline.

"Our target is nitrogen fluxes and influencing factors in China and Africa, with other regions as a reference." "One of the advantages of global-scale research is that there is a gradient comparison, for example, China has the largest point of nitrogen use and Africa is the smallest point, and if you connect these two points and put Europe, the United States, the Middle East, South America and other regions on this line, you can have a clearer understanding of the impact path of the nitrogen cycle." ”

"In the future, if we make this model, we will be able to know what the nitrogen flux is in each region, each year, and each type of nitrogen in the world, so as to promote the implementation of nitrogen management policies in different regions." He added.

Sail for a journey of cooperation

Which global nitrogen pollution pathway has the greatest impact? Gu Baojing said that current research shows that 80%~90% of global nitrogen pollution comes from agriculture, of which planting and breeding industry each contribute about half. In addition, agriculture is also a major source of pollutants in water bodies, accounting for more than half of the pollution.

Still, he said, nitrogen fertilizer use feeds half of the world's population, and optimal management does not mean banning it, otherwise it will lead to a significant reduction in food production. For example, in Sri Lanka, agriculture collapsed after a blind ban on the import of fertilizers, triggering a food crisis.

"Through this research, we hope that the people of China and Africa will understand the importance of nitrogen fertilizers and optimize the use of chemical fertilizers." Gu Baojing said.

Taking China as an example, he and his team have repeatedly calculated that if the amount of agricultural fertilizer used in the country is reduced by about 1/3 by optimizing fertilization methods, such as deep mechanical application, combination of fertilization and irrigation, and increasing the use of organic fertilizer, it will not have a great impact on agricultural output.

However, Gu Baojing found in the grassroots survey that for farmers, under the current conditions of relatively backward smallholder management technology, fertilizer based on yield is usually the first choice. "Most of the mainland's annual grain output of 680 million tons is produced by small farmers, and it is very difficult for farmers. With the decline of rural productivity conditions, it is necessary to pay attention to new main operations such as large-scale production and managed planting in the future to help farmers achieve transformation. Gu Baojing said.

He said that today many parts of Africa are still unable to produce and supply fertilizers. The fertilizer industry needs a strong industrial synthesis base, which is not sound in Africa, resulting in many parts of Africa need to import fertilizers from the West, and the high cost of agricultural inputs directly affects local food production.

"Africa has good natural conditions for the development of agriculture, and if the level of agricultural modernization is further improved, it can feed more people and promote the further development of industry, service industry, and even modern high technology." Gu Baojing said.

In June this year, Gu Baojing traveled to Kenya to attend the China-Africa Ecological Conference. There, he saw many roads, toll stations, houses, and water conservancy facilities built by Chinese, and also saw China's contribution to the development of fraternal African countries. Through this China-Africa cooperation in the field of nitrogen, he firmly believes that China-Africa cooperation will achieve greater achievements in the future.

"In addition to infrastructure, agriculture is also the most important aspect of development in Africa." Gu Baojing said that in the process of achieving carbon neutrality, China is currently controlling nitrogen pollution, which means that the nitrogen field is in the process of de-capacity in China, while Africa is facing a situation of increasing production capacity. In this context, China can provide assistance to more countries and regions in Africa, Southeast Asia, South America and other countries and regions with fertilizer shortages, and promote balanced regional development for the benefit of many parties.

Gu Baojing said that there is a law of "inverted U-shaped" curve in the application of chemical fertilizers in the world. China has experienced the insufficient use of chemical fertilizers and low grain production, and is currently on the way to the downward trend of this curve. China's experience of fertilizer application "from ramp-up to downhill" is extremely important for other developing countries.

"We hope to achieve a win-win situation through China-Africa cooperation, export China's technologies, solutions or strategies for global nitrogen management, and promote the sustainable development of Belt and Road brother countries." Gu Baojing said.