Irrigation districts play a decisive role in Portuguese agriculture and require the adaptation to the new water management paradigm through a change in technology and practices compatible with farmers’ technical know-how and economic sustainability. Therefore, improvement of water management, focusing on water savings and increasing farmers’ income, is a priority. In this perspective, an applied research study is being carried out on the gravity-fed Lis Valley Irrigation District to assess the performance of collective water supply, effectiveness of water pumping, and safety of crop production due to the practice of reuse of drainage water. The water balance method was applied at irrigation supply sectors, including gravity and Pumping Irrigation Allocation. The average 2018 irrigation water allocated was 7400 m³/ha, being 9.3% by pumping recharge, with a global efficiency of about 67%. The water quality analysis allowed identifying some risk situations regarding salinization and microbiological issues, justifying action to solve or mitigate the problems, especially at the level of the farmers’ fields, according to the crops and the irrigation systems. Results point to priority actions to consolidate improved water management: better maintenance and conservation of infrastructure of hydraulic infrastructures to reduce water losses and better flow control; implementation of optimal operational plans, to adjust the water demand with distribution; improvement of the on-farm systems with better water application control and maintenance procedures; and improvement of the control of water quality on the water reuse from drainage ditches. The technological innovation is an element of the modernization of irrigation districts that justifies the development of multiple efforts and synergies among stakeholders, namely farmers, water users association, and researchers.

Electrical Impedance Spectroscopy, EIS, is widely used in the study of electrical properties and structure of biological tissues, namely in quality control of fruits and the characterization of specific botanical tissues. The present work aims to extend the EIS concept to identify structure damaging pathologies for in vivo vegetal tissue. This allows for the early detection of specific plant diseases with economic and environmental impact. Moreover, the commercially available EIS solutions miss a true frequency bandwidth analysis and, despite the general good performance, are unspecified for bioimpedance measurements and are often quite expensive. Consequently, these limitations are the main reason for erroneous interpretations and inaccurate results. Therefore, this work proposes the development of a dedicated bioEIS system, characterized by an appropriated frequency range (1kHz to 1MHz), suitable for biological applications, in such a way that it becomes possible to compensate the influence of potential errors in off-line analysis.

Society’s demand for the preservation of water resources has stimulated technological advances and improved agricultural management, to limit its negative impacts, favor socio-economic development and promote the conservation of natural resources. This study assessed the impact of a rice farming system in the Mediterranean area on the microbiological quality of water, representing the irrigation and cultivation conditions of the Lis Valley Irrigation District (LVID). Indicators used include the counting of total coliforms (TC), fecal coliforms (FC), fecal enterococci (FE) and ampicillin-resistant Enterobacteriaceae (Amp^r), and a phenotypic characterization of antibiotic (AB) resistances. The results show that the water at the LVID inlets contained high microbiological contamination due to sources outside the perimeter. The rice paddy agroecosystem had a beneficial impact on the load of TC, FC and FE of the respective drainage water, with a decrease of two orders of magnitude between the values of these counts at the inlets and at the outlets of the rice fields. However, the relative frequency of Enterobacteriaceae Amp^r increased in the rice paddy soil, possibly as a result of the favorable conditions provided by this wetland ecosystem for the transfer of AB resistance genes. The analysis of AB resistance patterns revealed high relative resistance percentages for both β-lactams and non-β-lactams in all samples. This study made it possible to assess the risks of microbiological contamination of irrigation water and the beneficial effect of the rice-growing system in controlling the applied indicators.