A promising nickel ferrite (NiFe2O4) NPs with excellent magnetic characteristics was synthesized using an aqueous-based reflux approach that eliminates the need for calcination temperature. The magnetic nanoparticles obtained were analysed using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and scanning electron microscopy (SEM). The analysis showed that synthesized nickel ferrite had a spherical shape with an average size ranging from 18 to 29 nm. The synthesized nickel ferrite is utilized for the removal of hexavalent chromium (Cr (VI)) and pentavalent arsenic (As (V)) ions from aqueous solution through adsorption method. The removal of Cr (VI) ions achieved a maximum efficiency of 65
The usefulness of estimating hourly reference evapotranspiration for assessing the water requirements of plants over a 24‐hour period was determined in the study. The values of hourly (ET0,h) and daily (ET0,d) evapotranspiration were calculated using the Penman‐Monteith (PM) model. The daily ET0 was calculated automatically by the meteorological station, and the evapotranspiration values for individual hours were calcu‐ lated using spreadsheet software. To verify the values of evapotranspira‐ tion calculated with these two approaches in relation to the actual water needs of grass, lysimetric measurements were performed. Additionally, substrate moisture content and temperature were measured using capac‐ itance probes. The values of evapotranspiration estimated with the hourly PM model were higher than those determined with the daily model. An ac‐ curacy of the hourly model in relation to the data measured with a weigh‐ ing lysimeter depended largely on the quality of the reproduction of me‐ teorological parameters at the site of the crop. Observed underestimation of the actual daily evapotranspiration was presumably due to the use of air temperature values in the calculations (measured at a height of 2 m by the weather station). During strong solar radiation the air temperature was much lower than the temperature of the upper layer of the substrate in the weighing lysimeter. Reference evapotranspiration was recalculated by introducing into the hourly PM model the measured values of substrate temperature. After taking into consideration the higher temperatures, the Waldemar Treder, Krzysztof Klamkowski 470 calculated values of evapotranspiration increased, and the regression mod‐ el took the form: y = 1.01x + 0.014 (R2 = 0.90), which proves the propor‐ tionality of the calculated and measured (actual water needs determined with the weighing lysimeter) data. Reliable data on the hourly variations in evapotranspiration over a 24‐hour period can be a great tool for use in controlling the irrigation of plants grown in a limited volume of substrate.
