912. World Soil Day 2023: Soil and water, a source of life

The United Nations World Soil Day is observed annually on 5 December to draw attention to the importance of healthy soil and to promote sustainable management of soil resources. This year's theme is "Soil and water, a source of life". World Soil Day 2023 and its campaign aim to raise awareness of the importance and relationship of soil and water in achieving sustainable and resilient agri-food systems.

The survival of our planet depends on the precious link between soil and water. More than 95 percent of our food comes from these two basic resources. Water in the soil is essential for the absorption of nutrients by plants and holds our ecosystems together. This symbiotic relationship is the foundation of our agricultural system.

However, climate change and human activities are degrading soils and putting excessive pressure on water resources. Soil erosion upsets the natural balance, reducing the permeability of water and the potential for water use by all living things.

Sustainable soil management practices such as minimum tillage, crop rotation, organic matter additions and cover crops can improve soil health, reduce erosion and pollution, and increase water infiltration and storage. The practice of these methods maintains soil biodiversity, improves fertility, contributes to carbon sequestration, and plays an important role in the fight against climate change.

Many African countries, in particular, are chronically dependent on food imports because improvements in agricultural productivity have not kept pace with the significant increase in food demand associated with population growth. In Africa, soil and water in particular are major constraints on food production, and improving food productivity requires a thorough understanding of soil and water and the adoption of sound soil and water management practices.

JIRCAS Initiatives

JIRCAS has long been engaged in research to contribute to the improvement of soil and water management technologies in Africa facing such problems, in collaboration with national and international research institutes and government agencies. Currently, we are working on the development of appropriate soil and water management technologies through the Africa rice farming and Africa upland farming system projects, with the aim of building resilient and sustainable food production systems in Africa. Recent topics include the following research results and activities.  

【Research Results 1】Estimation of the Impacts of Climate Change on Cowpea, an Important Crop in Semi-Arid Region of West Africa, through Yield Prediction Model―Highlighting the dual challenge for excessive soil humidity and drought―

・Accuracy of yield prediction of cowpea, an important crop in West Africa, under excessive soil humidity and drought has been improved by analyzing field data.
・Due to climate change, the rainfall frequency in semi-arid region of West Africa is expected to increase, causing reduction in cowpea yields in soils prone to excessive humidity in high-rainfall years.
・These results suggest that not only drought but also excessive soil humidity need to be addressed in semi-arid region of West Africa.

【Research Results 2】Understanding yield-limiting factors for sorghum in semi-arid sub-Saharan Africa: beyond soil nutrient deficiency  

・The study demonstrated that water deficit also limits crop yield in semi-arid areas of Sub-Saharan Africa
・In addition to the lack of soil nutrients being the limiting factor in sorghum cultivation under unfertilized conditions, regardless of soil type, lack of soil water becomes a limiting factor in soils with an effective soil depth of  less than 50 cm under fertilized conditions. 
・In order to achieve food security in this region, it is important to develop efficient fertilizer application methods according to effective soil depth.

【Research Results 3】Evaluation of Fertilizer Management, Yield and Sustainability in Rice Plots in Sub-Saharan Africa

・The relationship between fertilizer management and yield in 235 rice fields in 24 sub-Saharan African countries was analyzed, and a high positive correlation between nitrogen and phosphorus application and rice yield was found.
・In about 40% of the fields, fertilizer application was inadequate for the amount of nutrients removed as crop products, raising concerns about long-term nutrient depletion from the soil. Proper management of phosphorus fertilizer is particularly important.
・Farmers tend to suppress fertilizer application in fields with unstable water conditions, such as high risk of drought and flooding. An approach that includes water management is needed to improve rice productivity and sustainable soil management.

【Activity 1】JIRCAS Launches TERRA Africa Project to Establish Regenerative Agriculture Suitable for Africa ―New JIRCAS initiative under the Nippon Foundation Program―

・JIRCAS launched the "TERRA Africa" project, which aims to establish regenerative agriculture suitable for Africa, under the overseas cooperation assistance program of the Nippon Foundation.
・On September 6, 2023, a ceremony was held in the Republic of Ghana to commemorate the launching of the project.
・The project promotes the development of soil and crop management technology suitable for Africa and its dissemination technology in cooperation with domestic and overseas organizations.

【Activity 2】TICAD 30th Anniversary Official Side Event: Emphasizing the Significance of an Inclusive Approach towards the Diverse Landscape of African Agriculture 

・On December 1, 2023, an official side event was held to commemorate the 30th anniversary of TICAD (Tokyo International Conference on African Development).
・Introduction of issues related to agriculture, forestry, and fisheries in Africa and Japan's contribution, history and current status of international joint research, and research needs.
・Discussion on the diversity of African agriculture in terms of crops, water resources, soil, microorganisms, agricultural management, and nutritional supply, as well as points that need to be taken into consideration and future international joint research.

JIRCAS will continue to work with national and international research institutes and government agencies to develop appropriate soil and water management technologies for the establishment of resilient and sustainable food production systems in Africa.

References

Iizumi, T., Iseki, K., Ikazaki, K., Sakai, T., Shiogama, H., Imada, Y., Batieno, B.J. (2023) Increasing heavy rainfall events and associated excessive soil water threaten a protein-source legume in dry environments of West Africa. Agricultural and Forest Meteorology, 109783, DOI : https://doi.org/10.1016/j.agrformet.2023.109783

Ikazaki, K., Nagumo, F., Simporé, S., Barro, A. (2023): Understanding yield-limiting factors for sorghum in semi-arid sub-Saharan Africa: beyond soil nutrient deficiency, Soil Science and Plant Nutrition, DOI: 10.1080/00380768.2023.2279582

Johnson, J.M., Ibrahim, A., Dossou-Yovo, E.R., Senthikumar, K., Tsujimoto, Y., Asai, H., Saito, K. Inorganic fertilizer use and its association with rice yield gaps in sub-Saharan Africa. Global Food Security, 100708. doi.org/10.1016/j.gfs.2023.100708 

United Nations, World Soil Day, 5 December, Soil and water, a source of life https://www.un.org/en/observances/world-soil-day

671. World Soil Day 2022 https://www.jircas.go.jp/en/program/proc/blog/20221205

Estimation of the Impacts of Climate Change on Cowpea, an Important Crop in Semi-Arid Region of West Africa, through Yield Prediction Model https://www.jircas.go.jp/en/release/2023/press202318

JIRCAS Launches TERRA Africa Project to Establish Regenerative Agriculture Suitable for Africa https://www.jircas.go.jp/en/release/2023/press202309

TICAD 30th Anniversary Official Side Event: Toward Building a Sustainable and Resilient Food System in Africa https://www.jircas.go.jp/en/event/2023/e20231201

Information Page on Agricultural Research in Africa https://www.jircas.go.jp/en/africa-research

Contributors: NAKASHIMA Kazuo (Food Program); IKAZAKI Kenta, NAKAMURA Satoshi and TSUJIMOTO Yasuhiro (Crop, Livestock and Environment Division); ISEKI Kotaro (Biological Resources and Post-harvest Division); SAKAI Toru (Social Sciences Division); KANAMORI Norihito (Information and Public Relations Office); IIYAMA Miyuki (Information Program)