More than 90% of the global natural rubber production originates from monoculture plantations in tropical Asia, especially from countries forming the Greater Mekong Subregion (GMS). Rubber cultivation is expected to further increase strongly in the near future, particularly at the expense of natural forests, and is accompanied by various problems and threats to farmers and the environment. Implications on carbon balance and hydrological conditions as well as socio-economic consequences referring to the situation in the GMS are reviewed. Results indicate considerable changes in ecosystem functions and services at different spatial and temporal scales with impacts on carbon stocks and sequestration, water quality and quantity, runoff and soil erosion. The long-term dependency on rubber as a single crop affects the socio-economic conditions and livelihood of the farmers and exposes them to economic and ecological hazards. Solutions for these interrelated problems require the development of alternative land-use systems and safeguarding important ecosystem functions and services on the one hand as well as providing economic viability on the other. Common suggestions include crop diversification and improved plantation management on the farm scale, and alternative land-use strategies including conservation and restoration of forest on the landscape scale. Successful implementation of more sustainable concepts is only feasible within a socio-economic framework, involving farmers and political decision-makers in the conceptualization process and the identification of trade-offs between ecological requirements and economic feasibility.

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Operational and structural interventions in the field of stormwater management are usually planned based on long-term simulations using rainfall-runoff models. The simulation results are often highly uncertain due to imperfections of the model structure and inevitable uncertainties of input data. The trend towards monitoring of combined sewer overflows (CSO) structures produces more and more data which can be used to replace parts of the models and reduce uncertainty. In this study we use highly resolved online flow and quality monitoring data to optimize static outflow settings of CSO tanks. In a second step, the additional benefit of real time control (RTC) strategies is assessed. In both cases the aim is the reduction of CSO emissions. The methodology is developed on a conceptual drainage system with two CSO tanks and then applied to a case study area in Southern Germany with six tanks. A measured time series of six months is sufficient for reliable optimization results in the conceptual catchment as well as in the case study area system. In the investigated system the choice of the optimization objective (minimum overflow volume or total suspended solids (TSS) load) had no significant influence on the result. The presented method is particularly suitable for areas in which reliable monitoring data are available, but hydrological parameters of the catchment areas are uncertain. One strength of the proposed approach lies in the accurate representation of the distribution of emissions between the individual CSO structures over an entire system. This way emissions can be fitted to the sensitivity of the receiving water body at the specific outlets.

Throughout the last decade, and particularly in 2022, water scarcity has become a critical concern in Morocco and other Mediterranean countries. The lack of rainfall during spring was worsened by a succession of heat waves during the summer. To address this drought, innovative solutions, including the use of new technologies such as hydrogels, will be essential to transform agriculture. This paper presents the findings of a study that evaluated the impact of hydrogel application on onion (Allium cepa) cultivation in Meknes, Morocco. The treatments investigated in this study comprised two different types of hydrogel-based soil additives (Arbovit® polyacrylate and Huminsorb® polyacrylate), applied at two rates (30 and 20 kg/ha), and irrigated at two levels of water supply (100% and 50% of daily crop evapotranspiration; ETc). Two control treatments were included, without hydrogel application and with both water amounts. The experiment was conducted in an open field using a completely randomized design. The results indicated a significant impact of both hydrogel-type dose and water dose on onion plant growth, as evidenced by various vegetation parameters. Among the hydrogels tested, Huminsorb® Polyacrylate produced the most favorable outcomes, with treatment T9 (100%, HP, 30 kg/ha) yielding 70.55 t/ha; this represented an increase of 11 t/ha as compared to the 100% ETc treatment without hydrogel application. Moreover, the combination of hydrogel application with 50% ETc water stress showed promising results, with treatment T4 (HP, 30 kg, 50%) producing almost the same yield as the 100% ETc treatment without hydrogel while saving 208 mm of water.

The pre-selection of locally appropriate sanitation technologies and systems is crucial for strategic sanitation planning as any decision is only as good as the options presented. One approach that allows us to systematically consider the local conditions and a diverse range of conventional and novel technologies and systems is the Santiago method. In this paper, we discuss whether the Santiago method can be applied to the case of Latin America and what we would gain from this application. We do so by expanding the Santiago technology library with technologies that have been shown to be promising in metropolitan areas of Latin America, such as condominial sewer, container-based sanitation, and activated sludge. We then apply Santiago to the semi-informal settlement Quebrada Verde (QV) in Lima, Peru. Using Santiago, we were able to generate 265,185 sanitation system options from 42 technologies and 18 appropriateness criteria. A set of 17 appropriate and divers are then selected. The diversity is defined by 17 system templates. To further evaluate these 17 systems, resource recovery and loss potentials are quantified. Higher nutrients (nitrogen and phosphorus) and total solids recovery are observed for systems that combine urine diversion and biofuel production. The case of QV shows that the Santiago method is applicable in the Latin American context.