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ABSTRACTWith the water crisis affecting several countries, the use of innovative technologies and methods in irrigated agriculture is essential to increase water use efficiency. The use of magnetised water has been considered a possibility both for saving water resources and in increasing crop productivity and quality. Following this, the objective of the present study was to evaluate the growth and longevity of flower stems of ornamental sunflower (Helianthus annuusL.; Vincent’s Choice) irrigated with different irrigation depths and water subjected to magnetic field treatment. The treatments consisted of five percentage of crop evapotranspiration (ETc) (20, 70, 100, 130, and 160% of ETc) and two types of irrigation water (magnetised water; and ordinary water). The following characteristics were evaluated: plant height, stem diameter, inflorescence diameter, fresh and dry masses of the leaves and stems, fresh and dry masses of the inflorescence, and post-harvest longevity of the flower stems. The growth and post-harvest longevity characteristics were not influenced by the water type. An increase in irrigation depth promoted an increase in all analysed parameters. Regarding the commercialisation patterns of cut flowers, depth equal to or greater than 0.7 ETc yielded the best classification of ornamental sunflower.

Due to the complexity, and variety of results obtained, depending on the design methodology chosen, the rainwater reservoir design is often carried out in an empirical way in Brazil. As an attempt to disseminate a practical and accurate design method, this study performed the sizing of rainwater reservoirs using the Yield After Spill (YAS) algorithm, then fitting mathematical models to the obtained results, using as independent variables: statistical parameters related to rainfall, the demand for non-potable water and the rainwater catchment area, for all the mesoregions of the State of Minas Gerais, Brazil. It was observed that from a certain value of demand for non-potable water, there was a change in the behaviour of the obtained reservoir volumes. Thus, it was necessary to divide the results into two behaviour regions––with ascending and descending trends. In general, for the first and second behaviour regions, a better performance was reached for the exponential and power models, respectively, measured by the coefficient of determination (R2). With these results, water resources technicians will be able to design the rainwater reservoirs in a simple and accurate way, avoiding unnecessary costs, such as the purchase of a reservoir with a larger volume than necessary or the expansion of the storage capacity.

This study aims to evaluate the filtration process of a commercial sand filter operating at different filtration rates and different sand particle sizes. The second objective is to carry out sand filter efficiency evaluations and compare the standard sand filter method and the proposed method. Removal efficiency was analyzed in three filtration cycles, and determined by two methodologies: counting of particles in water at the inlet and outlet of the filtration system (standard method) and in sand bed layers (proposed method). An experimental module composed of three identical commercial sand filters was used with different sand particle sizes (G1 – 0.55 mm of sand effective diameter, G2 – 0.77 mm and G3 – 1.04 mm) and filtration rate combinations (20, 40, 60, and 75 m3m–2h–1), repeated for three filtration cycles (C1, C2 and C3), 4 h per cycle. The removal efficiency of sand filters increases as the filtration rate increases for the water quality used, and sand particle size decreases. Between the methodologies applied to evaluate filtration systems, the method using total suspended solids retained in sand (proposed method) has shown a greater potential when compared with the standard method. The evaluation methodology proposed provides a global and accurate evaluation of the process. This form of estimation does not have the representability problem punctual water samples collected during filtration have. In addition, it is a promising methodology for farmers and technicians to carry out equipment evaluations in the field.