The 9th Pacific Islands Leaders Meeting (PALM9) will be held online on July 2, 2021. The PALM is an international conference that has been organized by the Government of Japan every three years since 1997 and is attended by 14 Pacific island countries (PICs), two French territories, Australia and New Zealand. Pacific island countries have common difficulties regarding their small size and land distribution over a wide area, distance from major international markets, and the vulnerability to natural disasters and climate change. To overcome these challenges, PALM is an important opportunity to discuss and enhance partnership at the summit level for regional stability and prosperity.

Tropical rainforests, mangrove forests and abundant coral ecosystems have been formed on the tropical islands, and people have lived with using benefits from ecosystems. These ecosystems have also played an important role in biodiversity and carbon cycle on the Earth. However, in recent years, environmental problems such as deforestation in tropical rainforests and mangroves, nitrogen load due to overuse chemical fertilizers on farmlands, and soil erosion from sloped agricultural lands have occurred, causing serious damage to coral reefs and marine environments. 

The Tropical Agriculture Research Front (TARF) of Japan International Research Center for Agricultural Sciences (JIRCAS) is located in Ishigaki Island, Okinawa where the climate is subtropical, we have been developing technologies using research facilities such as field erosion plots and lysimeters. Until now, we have conducted a number of research activities in Ishigaki Island and island countries such as Palau and the Marshall Islands which are part of PICs, and the Philippines in Southeast Asia, with making maximum use of the facilities and the conditions of their location in order to develop technologies to solve the problems facing in each country. Recently, we have published a book titled "Agriculture in Palau" in which achievements in TARF and Palau are summarized. This book describes improved technologies for agricultural production with mitigating soil erosion in response to the level of soil erosion risks on slopes. We highly expect that the book will be actively utilized by farmers, researchers and the governments in Palau and other PICs. Other achievements in technological development are listed below and further information can be referred to in the research highlights on the JIRCAS website.

●Nitrogen leaching and growth of sugarcane under different nitrogen fertilization levels in a subtropical island.

●Modified conservation agriculture for taro production in combination with spot excavation by gas-powered apparatus and organic mulch. 

●Countermeasures against freshwater lens pollution on atolls should consider the groundwater residence time 

●Difficulty in restoring salinized freshwater lens, a valuable water resource of atoll islands

●Estimation of nitrogen load to groundwater at a sugarcane monocropping area in the Philippines

●Extraction of gully erosion-affected areas by image analysis of high spatial resolution satellite data

●Runoff of suspended solids, nitrogen and phosphorus estimated from catchment basins of Miyara River on Ishigaki Island

In the research project, “Yama-Sato-Umi agroecosystem connectivity”, started in April 2021, we aim to build a healthy material cycle from the mountains to the sea through developing technologies for reducing the environmental load and resource recycling. 

Japan is also an island country, and the mountains and the sea are closely connected through the material cycle. The deterioration of the environment in mountains and villages affects the sea as they say ”The sea is longing for the forest”. Especially for islands where the mountains and the sea are continuous with a short distance, integrated research from the mountain to the coastal ecosystem is very important for contributing to island sustainable development.

Contributor: ANZAI Toshihiko (Project Leader, TARF)