We analysed the river water quality of Rekifune River and Satsunai River watersheds, which are evaluated as a clear stream in Tokachi region, Japan with the principal component analysis (PCA) and the cluster analysis to interpret complex water quality data and to evaluate factors affecting river water quality on the basis of a 2008 investigation. The mean pH was neutral and stable, also the mean BOD, SS and EC were relatively low. However, T-N concentrations tended to be high in Satsunai River watershed. The PCA and cluster analysis integrated the trend of water quality to two main components and classified the sampling points into three clusters. From the results, the river water quality of Satsunai River watershed was deteriorated by agricultural impacts, whereas the river water quality was preserved in Rekifune River watershed. Furthermore, three sampling points affected by the point source were classified in both river watersheds. It is necessary to develop a framework of agricultural impacts on Satsunai River watershed to improve the river water quality. An equally important priority is to control the loads from agriculture in some parts of Rekifune River watershed to maintain good water quality.

There is a myriad of issues that form our global crisis of climate change and the destruction of the environment. If we are to develop sustainable practices that can help reverse the destructive trends, we need revolutions across a range of industries. The agricultural industry is huge, globally essential activity that will always be with us. It is intimately tied to the environment and has multiple direct impacts on it. Naturally, the world will always require food, whether that be from livestock or crops. Therefore, we need to continue improving our agricultural practices if we are to sustain the global population. Livestock pose a particular set of questions as to how best maintain them. They take up significant space, consume a lot of vegetation and produce a lot of waste. Whilst avoiding and reducing meat consumption is a growing social movement, this will never eliminate meat consumption and only further emphasises how we should rear livestock in a sustainable and non-destructive manner. Typically, livestock such as cattle are raised on large areas of meadows and grasslands. The more cattle you are looking to raise, the greater the amount of land needed. Where they feed has a profound impact on the environment around them. They can alter the vegetation growing and their waste can affect the water system. When it rains, their waste seeps into the soil and then into streams and rivers. Rivers are basins for large areas of grassland and likely multiple cattle farms. This means a huge multiplication of waste run off from livestock rearing. Dr Yuri Yamazaki of the Faculty of Regional Environment Science, Tokyo University of Agriculture is investigating alternative methods of cattle rearing. This work has developed directly from her doctoral studies which were aimed at evaluating the impact of dairy farming and upland farming on river water quality. This work led her to exploring the forest grazing of cattle as a potential alternate way of maintaining livestock. She is now working hard to evaluate this proposition.

Groundwater-dependent irrigated agriculture in semi-arid basins is increasingly threatened by climate variability and aquifer depletion. Karapınar district, located within Türkiye’s Konya Closed Basin, represents a water-stressed melon-producing area where deep-well drip irrigation and rigid calendar-based scheduling remain common. This study developed a prototype AquaCrop-based decision-support framework for adapting mature and pickled melon irrigation to climatic conditions classified by the crop-season weighted three-month Standardized Precipitation Index (SPI-3). SPI-3 was selected to represent short-term seasonal precipitation anomalies relevant to agricultural water availability, and three historical years were used as representative scenarios: Dry (2020), Normal (2018), and Wet (2017). Fourteen irrigation treatments, including farmer practice and phenologically targeted Late-Season Event (L.S.E.) deficit strategies, were simulated using FAO AquaCrop v7.1. Irrigation timing was more important than seasonal irrigation volume alone. Under Normal conditions, an L.S.E. strategy that redistributed irrigation toward four late fruit-development events (T4.2) maintained yield stability comparable to farmer practice (CV < 2%), increased mature melon yield by 12.7% relative to farmer practice, and reduced applied irrigation by 19–21%. Under Dry conditions, a lower-volume L.S.E. strategy with the same late-season targeting (T4.3) maintained baseline-level yield while reducing applied irrigation by 28–31%. The resulting SPI-based decision matrix is forecast-compatible but not operationally validated; field validation, long-term climate testing, and forecast-skill evaluation remain necessary before deployment.