Yutaka Matsuno

Prospects for multifunctionality of paddy rice cultivation in Japan and other countries in monsoon Asia

This paper presents a study carried out by a group of Japanese researchers to critically review past researches and discussions on the multifunctionality of paddy rice cultivation, with the aim of describing the current status of the subject and providing options and potentials for future research and practices. The review was of over 200 documented articles on the major external functions. The results of this study revealed that the importance of multifunctionality is well perceived in Japan. The methodologies to measure and estimate the magnitude have been established for most functions. However, there is a need for more cases, to integrate all the functions at the local or regional scale to represent site-specific characteristics of multifunctionality. There is also a need to develop management practices to sustain and enhance the positive multifunctionality of paddy rice cultivation while minimizing negative effects to the environment, which may be brought into the agricultural policies. Except for Korea, Taiwan, and Japan, there are slightly different notions on multifunctionality in other monsoon Asia countries, but the gap in this notion is reducing following recent international activities.

Control of Malaria Mosquito Breeding through Irrigation Water Management

In the dry zone of Sri Lanka, an interdisciplinary study was conducted to evaluate the effects of irrigation water releases on malaria mosquito breeding and to identify different water management options for vector control. The relationship between abundance of larvae of the vector, Anopheles culicifacies (An. culicifacies), and the water level in a stream was described mathematically.An inverse function was derived and incorporated into a water balance model developed for the area. The larval abundance was quantified under different irrigation and water management scenarios. The result demonstrates potential for effective vector control by feasible changes in irrigation management.

Transfer of water from irrigation to other uses: lessons from case studies

The papers in this special issue deal with a subject that is of major concern in many countries—the transfer of water from agriculture to urban uses. The work arose out of a concern by the Taiwan government to learn from other country experiences. As a results of this interest in 2006 with the support of the Agricultural Engineering Research Center, the Council of Agriculture in Taiwan, and the International Water Management Institute the study was undertaken with the following three objectives: (1) to identify the range of processes to facilitate the transfer of water from agriculture to other water user sectors, (2) to identify the conditions necessary for the success of the process, and (3) to identify and evaluate the procedures by which compensation levels are determined for the water to be transferred. To accomplish these objectives we conducted a comprehensive review of the literature on water transfer. We commissioned eight case studies of inter-sector water transfer under a variety of physical and socio-economic conditions. We then developed a framework for analyzing the experience of the case studies, characterizing the transfer process and the means of compensation. The lead or overview article draws on the case studies to present the framework: the water transfer characteristics, the form of compensation, procedures for setting price, and finally the policy considerations. This is followed by the case studies from Chile, India, Japan, Mexico (two), China, Taiwan, and the USA. While the case studies themselves are largely factual rather than analytical, they fill a gap in the literature by describing the range of forces and processes which initiate the transfer process and determine its final nature.

Multifunctionality of paddies

This special issue deals with multifunctionality as it applies to paddy rice production in east and southeast Asia. The range of papers reflects not only the broad interest but also the complexity of the topic. These reports are based on the research supported by a range of national agencies (e.g. National Institute for Rural Engineering) and the International Water Management Institute headquartered in Sri Lanka. The term “multifunctionality” entered agricultural policy discussions in the early 1990s and its use has spread to trade policy discussions in recent years (Bohman et al. 1999). While the term is relatively new, the concept it represents is not. The basic idea is that agriculture, or in our case paddy rice production, is more than just producing and selling commodities. There are important non-commodity attributes associated with agricultural production. Some views of multifunctionality encompass a wide range of attributes, including those related to land use such as wildlife habitat, biodiversity, and landscape amenities as well as social attributes such as agriculture’s contribution to cultural heritage, the viability of rural communities, and food security. In other cases, the focus is primarily on the environmental attributes of agricultural production.

Characteristics of Drainage Water Quality and Loading from Paddy Field under Cyclic Irrigation and Its Management Options

The cyclic irrigation system has been practiced in Japan for reducing pollutant outflow loadings from paddy fields. The cyclic irrigation is an irrigation method to reuse water by pumping drainage water and re-distributing it to the farmland. Quantification and assessment of the effects of the cyclic irrigation are needed to identify management options for maximizing the benefits of cyclic irrigation. The study was aimed at assessing loading characteristics from paddy field area under the cyclic irrigation and developing a model for simulating water and material flow in paddy field area that can be used as a management tool. The study was carried out in a paddy field in the Asagoi District, Oumihatiman city in Shiga Prefecture, Japan. Using the results of water quality analysis, the average net loadings of T-N and T-P were estimated for both cyclic and non-cyclic irrigation sites. The result indicates a higher nutrient absorption rate in the cyclic irrigation site than that in the non-cyclic irrigation site. The developed cyclic irrigation model showed good agreements between observed and simulated drainage volumes and nitrogen loadings. The scenario analysis by application of the model showed a potential of reducing the loading amount by increasing the cyclic irrigation ratio and reducing the amount of fertilizer application without affecting the rice yield.

Dr. Yohei Sato's donation to PAWEES

Dr. Yohei Sato, a founding member and Past President of PAWEES made a cash donation on 1 April 2005 for further development of the International Society of Paddy and Water Environment Engineering (PAWEES). The donation was handed over to Dr. Kazumi Iwasaki, Executive Director of the Japanese Society of Irrigation, Drainage, and Reclamation Engineering (JSIDRE) who assured his continuous support to PAWEES based on his understanding of the importance of advancing this discipline worldwide and his experience during his tenure as President from January 2003 to December 2005. PAWEES was established in January 2003 by Korean, Taiwanese, and Japanese professionals to contribute to the development of science and technology in land, water and