Saline water irrigation strategies and potassium fertilization on physiology and fruit production of yellow passion fruit

ABSTRACT The objective of this study was to evaluate the effects of saline water irrigation management strategies and potassium doses on the concentration of photosynthetic pigments, gas exchange, and fruit production of ‘BRS GA1’ yellow passion fruit. The experiment was carried out under field conditions using a randomized block design, with treatments based on a 6 × 2 factorial scheme, related to six management strategies for irrigation with saline water (irrigation with low-salinity water throughout the crop cycle-WS; irrigation with high-salinity water in the vegetative stage-VE; flowering stage-FL; fruiting stage-FR; and successively in vegetative/flowering stages-VE/FL and vegetative/fruiting stages-VE/FR) and two doses of potassium (60 and 100% of the recommendation), with four replicates. The dose of 100% recommendation corresponded to 345 g of K2O plant-1 year-1. High electrical conductivity irrigation water (4.0 dS m-1) was used in different phenological stages according to treatment, alternating with water of low electrical conductivity (1.3 dS m-1). The synthesis of chlorophyll a and b, stomatal conductance, instantaneous carboxylation efficiency and water use efficiency of ‘BRS GA1’ yellow passion fruit were reduced under irrigation with water of 4.0 dS m-1 in all strategies adopted. Fertilization with 60% of the K recommendation promoted greater number of fruits and yellow passion fruit yield. Irrigation with 4.0 dS m-1 water in the vegetative/flowering and flowering stages reduced the yield of yellow passion fruit.

Gas exchange and millet phytomass under organic fertilization and graywater irrigation

ABSTRACT Graywater is an alternative method to increase the water supply for agricultural production in semi-arid regions. The objective of this study was to evaluate the effects of different irrigation depths of graywater on the gas exchanges and phytomass of millet plants with and without organic fertilization. The research was conducted under greenhouse conditions in Serra Talhada municipality in semiarid region of Brazil, in a randomized complete block design with a factorial (4 × 2 + 1) plot and three replicates. The first factor corresponded to graywater irrigation depth equivalent to 25, 50, 75 and 100% of the available water content of the soil, and the second factor was the addition of bovine manure as fertilizer (0 and 34 Mg ha-1), and a control (irrigation with low-salinity water). Irrigation with graywater effluent did not promote adverse effects on gas exchanges and phytomass accumulation; however, it also did not provide enough nutrients to promote increase in these variables. The reduction in irrigation depth caused a decrease in gas exchange from 45 days after the application of the treatments. The basal tiller mass was the most favored plant component due to organic fertilization.

Tendency of Change in Water Quality of the Main Shirvan Collector Over a Long Period

The article examines the tendency of changes in the hydrochemical regime of the water of the Main Shirvan collector over a long period of time and the suitability of the collector water for irrigation. Continuous laboratory analyzes performed between 2004 and 2019 were compared to 1986. According to experimental data, it was determined that the hydrochemical regime of the collector water is gradually improving, and the salt content is decreasing. The degree of mineralization of the collector water decreased by 2.3 times, the total hardness by 2.2 times, the number of chloride ions by 10.5 times, the number of calcium ions by 1.3 times, the number of magnesium ions by 2.8 times, the total number of cations sodium and potassium decreased by 3.9 times. For 2004–2019 biochemical oxygen consumption in collector water increased 7.9 times, chemical oxygen demand increased 7.5 times, and the number of suspended particles increased 9 times. The amount of iron ions in water decreased by 2 times, while the amount of aluminum and zinc did not change. The suitability of collector water for irrigation was determined according to 7 internationally accepted assessment criteria. Collector water is considered suitable for irrigation in accordance with 6 assessment criteria — the degree of salinity, irrigation coefficient, sodium sorption coefficient, potential salinity, water alkalinity index and percentage of sodium, as well as 1 criterion not suitable for irrigation — the percentage of magnesium. Collector water can be used to irrigate crops.

Cellulose Blended Membranes for High-Salinity Water Pervaporation Desalination

In the current study, cellulose acetate (CA)/cellulose triacetate (CTA) nanocomposite membranes blended with zirconium dioxide (ZrO2) are prepared via phase inversion for pervaporation desalination performance. ZrO2 nanoparticles are added to enhance the hydrophilicity and porosity of the nanocomposite membranes. The fabricated nanocomposite membranes are characterized by SEM, FTIR, TGA, and DSC to study the surface morphology, chemical composition, thermal stability and strength. Nanocomposite membranes’ performance for pervaporation desalination is assessed as a function of feed concentration. Pervaporation results revealed that the nanocomposite membrane consisting of 2% ZrO2 achieved a maximum water flux of 6.5 kg/m2h, whereas the salt rejection was about 99.8%.