Japanese agriculture is facing a decrease in agricultural workers. Mechanization, both to save time and reduce physical input, is essential to solving this issue. Recent worldwide progress in Internet-of-things technology has enabled the application of remote-controlled and unmanned machinery in agriculture. This study was conducted in the Gojo-Yoshino mountainous region in Nara, Japan, which is famous for its persimmon cultivation. The performance of newly introduced smart agricultural machinery was studied in the field by simulating cultivation work. The results showed that the remote-control weeder, speed sprayer, and remote-control mini crawler carrier saved 90%, 75%, and 5% of weeding, spraying, and harvesting times, respectively, when compared with conventional methods. Such time savings led to an 8% decrease in the total working time spent on persimmon cultivation. In addition, using the speed sprayer showed improvement in the fruit’s quality. Results of the power assist suits did not show a time-saving effect but showed a reduction of physical burden. These results suggest that the mechanization of persimmon cultivation is efficient and labor-saving, and satisfies the need for farmers. However, the high investment costs remain an issue in extending mechanization to the region.

In this study, we aimed to develop and assess a hydrological model using a deep learning algorithm for improved water management. Single-output long short-term memory (LSTM SO) and encoder-decoder long short-term memory (LSTM ED) models were developed, and their performances were compared using different input variables. We used water-level and rainfall data from 2018 to 2020 in the Takayama Reservoir (Nara Prefecture, Japan) to train, test, and assess both models. The root-mean-squared error and Nash–Sutcliffe efficiency were estimated to compare the model performances. The results showed that the LSTM ED model had better accuracy. Analysis of water levels and water-level changes presented better results than the analysis of water levels. However, the accuracy of the model was significantly lower when predicting water levels outside the range of the training datasets. Within this range, the developed model could be used for water management to reduce the risk of downstream flooding, while ensuring sufficient water storage for irrigation, because of its ability to determine an appropriate amount of water for release from the reservoir before rainfall events.

Actual crop evapotranspiration (ET) and crop coefficient (Kc) of ratoon rice crop, which are necessary for irrigation planning, have been hardly reported. ET can be directly measured by lysimeter and eddy covariance but it is expensive, so it remains difficult to determine ET, especially in developing countries. The focus of this study was to evaluate the ET and Kc of ratoon cropping in a tropical region of Myanmar using a simplified method. Our method combined the manual observation of water depth in concrete paddy tanks and the ET model estimation using Bayesian parameter inference. The ET and Kc could be determined using this method with an incomplete observation dataset. The total ET of ratoon was 60–70% less than that of the main crop, but this difference was mainly attributed to climate conditions in each cultivation. The Kc regression curve between transplanted rice and ratoon crops was different because of the tillering traits. The results suggest that irrigation scheduling of ratoon cropping in the initial growth stage should take high crop water requirements into account. In addition, the productivity of ratoon crop is equivalent to transplanted rice, which was determined for cultivation in experiment conditions of small concrete tanks. Therefore, further study on ratoon in Myanmar is necessary for clarifying the viability of ratoon cropping.

The case study is aimed at assessing impacts of on-farm level irrigation development and management on dry season rice production in the main irrigated rice production area of Myanmar. The study was carried out from 2003 to 2009 in the middle reaches of the Ngameoeyeik irrigation area of 28,000 ha. In addition to collecting information on water management and institutional arrangement of the study area, hydrologic and agronomic parameters were monitored during the study period. Results showed the effectiveness of on-farm level infrastructural development for increasing rice productivity owing to increased amount of water delivery, increased flexibility of water distribution, and improved drainage conditions. Besides, encouraging the involvement of farmers in design and implementation of the development led to improved farmer participation in the operation and maintenance of the irrigation system. The outcomes of this study demonstrated the importance of balancing between infrastructural and institutional development in irrigation systems of Southeast Asia. Such infrastructural development should be in close association with institutional development and capacity building, and the interactions between those two aspects should be well understood.

[Synopsis] GDP share of Australian agriculture is only 2.2％, but the export share of agriculture is 12％, which has declined from 65％ in 1960-61. About 60％ of agricultural production is for export, and Japan is the biggest importer of Australian agricultural products. Wheat, barley, beef and milk products from Australia have relatively large share in Japan. In this regard, the agricultural production in Australia has a direct impact on the import and food availability in Japan. After 2000, Australia experienced severe and prolonged droughts and climate variability, and the agricultural export of Australia has been in declining trend, which could pose serious threat to the food security in Japan. In this study, Australian agriculture is analyzed from the point of limited water resources with average annual rainfall of 472 mm. Agricultural sector is the biggest user of water in Australia, consuming about 65％ of available water. To overcome the variability of rainfall and water shortage, water market and trading was introduced in the 1980s, which has become very active in recent years. Conditions and impacts of water market and trading are analyzed to understand the future prospects of water and Australian agriculture.

Understanding of vegetation conditions is needed to establish an appropriate management and resource utilization system for satoyama （community forestry）. Vegetation condition was investigated at 100 sites of 100m^2 ［10 m × 10 m］ plot each in Nara Campus satoyama, focusing on the woody plant community from June through December of 2008. The spermatophytes and fernery plants were collected, and 153 species of woody plants and 123 species of herbaceous plants were identified. Among these, there were 164 species of medicinal plants and 23 species of naturalized plants, of which 15 were endangered species. The forest floor is dark without proper forest management and the diversity of vegetation is poor. Invasion by Phyllostachys pubescens, and Pinus densifora, and thick growth of Pleioblastus fortunei and vines as well as illegal disposal of garbage were observed. Moreover, 14 species of naturalized plants occupy the greening slope of the campus, with a relatively high. naturalization rate of 41.6％.Understanding the conditions of satoyama is one challenge,and managing it is another. Utilizing satoyama as a place for research and education will increase the opportunity for maintaining and managing it properly.

Agricultural water reorganization measures (AWRM) is an approach that has been adopted in Japan for more than 30 years to capture excess water from agriculture for other uses by relying on the modernization of existing irrigation infrastructures. This paper reviews the history and processes of four such permanent water transfers by AWRM in the Tone River Basin, specifically those conducted in the Saitama Prefecture, Japan. The benefit of AWRM for the agricultural sector is the lowering of rehabilitation costs by sharing part of it with the city sector. AWRM does not require saving water at the on-farm level. Instead, the labor requirement of farmers is reduced by the rehabilitation and installation of pipelines. The benefit to the city is the lower cost, when compared with costs for the development of new water resources, and the relatively short duration of the project, which are important factors in an environment of the rapid increase in domestic water demand.

This paper presents protocols for estimating the magnitudes and monetary values of two non-market outputs from paddy rice production. The protocols were developed during a workshop held in Taiwan in 2004 to set guidelines or protocols for measuring the multi-functional attributes of positive and negative externalities of paddy rice. The externalities attributed to paddy rice include groundwater recharge, subsidence reduction, flood damage amelioration, change in water quality, change in air quality, and preservation of scenic value. Methodologies were set forth for measuring and valuing each of these externalities. Two that reflect differences in complexity - groundwater recharge and change in air quality - are discussed here. The protocols consider regional variation, the need for evaluation of net effects, and the avoidance of double counting. The conclusions presented are those from the workshop as a whole.

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.

Four different water sources (irrigation canals, small reservoirs, shallow wells, and tubewells), used for domestic purposes, in an irrigated area in southern Sri Lanka, were tested for Giardia spp. cysts and Cryptosporidium spp. oocysts. Identification of these parasites in water sources is important as these are increasingly recognized as causative agents of waterborne diarrhoeal disease. All the four sources of water were contaminated with cysts and oocysts. The sources of surface-water contained a greater number of protozoa compared to tubewells and shallow wells (p < 0.05). The results indicate a reduction of high parasite loads by natural filtration as the water moves from canals to shallow wells through the soil profile. This could present an opportunity to reduce the burden of diarrhoeal disease due to protozoa by selecting an appropriate source of drinking-water and identifying those water sources that require treatment solutions.

In many developing countries a close linkage exists between drinking and irrigation water; however, the effects of irrigation management on drinking water availability and quality, and what drinking water supplies are best suited to irrigated areas, have been little studied. Bacterial contamination and salinity of drinking water sources in a community within the Uda Walawe irrigation system of southern Sri Lanka were monitored from August to December 2000. Water with the lowest combination of faecal contamination and salt content (highest quality) was found in shallow wells, recharged with seepage water from the irrigation system. Of these wells, those surrounded by a protective wall had the lowest levels of thermotolerant coliforms (median of 244 ThCU 100 ml(-1)) as compared to shallow wells without protective walls (549 ThCU 100 ml(-1)). Furthermore, tube well waters were highly saline (average of 0.67 mS cm(-1)), while canal and reservoir waters had high thermotolerant coliform levels (3940 and 950 ThCU 100 ml(-1)). Interseasonal canal closures eliminate the canals as a water source, lowering water levels in shallow wells, and thus reducing regional water availability. Concrete lining of canals may exacerbate the drying up of shallow wells during canal closure, therefore eliminating the primary source of water in the region that can be used for drinking after only simple treatment. Copyright (C) 2002 John Wiley Sons, Ltd.

水田用IoT水門を設置した調査対象水田圃場において、水門開閉の操作と、田面水温・地温分布等の温度環境の変化を計測し、モデル検証のためのデータを収集した。日射、気温、湿度、風速等の基礎的な気象データを観測するとともに、IoT水門の開度データおよび用水路水位から水田内への取水流量を換算し、自記式水位・温度計にて水田内の湛水深、田面水温・地温の分布を連続測定するほか、プラント・キャノピー・アナライザーを用いて定期的に葉面積指数（LAI）の計測を実施した。 田面水の平面2次元流シミュレーションについては、稲株の周囲を流れる田面水の流れ場を計算可能な流体解析シミュレーションモデルを、微細計算格子に基づく有限体積法を用いて構築し、任意の湛水深、流速、稲株の太さ、稲株配置の間隔に応じて計算を行うことにより、さまざまな条件下における稲株群による流れへの抵抗をモデル化した。この結果を用いて、田面水が水田内のどの場所をどの程度の速度で流れるかをシミュレートする、田面水の平面2次元流数値計算モデルを構築した。 水田内の熱収支シミュレーションについては、物理則に基づく既存のアプローチのほか、機械学習（LSTM: Long Short-Term Memory）を適用した手法、物理則と機械学習を融合した手法（PGNN: Physics-Guided Neural Networks）についてもモデルを構築し、それらの性能を比較検証した。

農地排水の循環利用（循環灌漑）は，水資源の有効利用や負荷削減による環境配慮の観点から重要と考えられる．そこで，琵琶湖沿岸域において，循環・非循環灌漑水田群を対象に，循環灌漑が年間の流出負荷に及ぼす影響を検討した．その結果，循環灌漑区では，灌漑期における平常時の排出負荷軽減が循環取水率の増加とともに期待されるが，一方で，出水時の一時的な排出負荷の増大や非潅漑期における集積負荷排出などにより，必ずしも排水再利用によって軽減された負荷のポテンシャルが活かされるとは限らないことが示された．

本研究では、ミャンマーを対象として、灌漑農業に関わる要因を分析することにより用水管理を改善する方策を模索することを目的とした．そのために，同国灌漑農業についての動向を他のアジア諸国と比較し分析するとともに、低平地域の灌漑区を選定し、水文観測、水利状況の調査、農民と担当行政官への聞き取り調査などを実施した． 結果として、対象地区において水供給量は需要量を満たしていたが水管理の柔軟性に課題があることが明らかになった．そして、水利施設の構造や末端施設の整備など物理的な課題を解決することに加え、システム全体の水管理制度の構築や農民主体となる水利組織のキャパシティを向上させる対策の必要性が示唆された．

国内(琵琶湖沿岸の西の湖流域および近畿大学内圃場)、ベトナム(ハノイ近郊)、タイ(チェンマイ近郊)の3カ国の小流域・地域での研究・調査に基づき物質循環モデルを策定し、持続可能な営農の在り方と、多面的機能を有効に発現させるためのメカニズムについて、明らかにした。研究の成果は、2010年10月に韓国で開催された2010年国際水田・水環境学会(PAWEES)国際会議において特別ワークショップ「持続可能な農業のための物質循環モデリング」を開催し、広くその成果を公表した。

ミャンマーの灌漑地区を対象に,圃場整備が乾期米収量および水管理に与える影響を評価した.結果として,圃場整備の程度が稲作面積および米収量に大きな影響を与え,かつ整備状況の改善が農民参加型の水管理を促すことが明らかとなった.さらに,アジア・モンスーン地域の途上国における水利施設整備および水管理の課題を研究結果から導いた.