Improving water resources management using different irrigation strategies and water qualities: Field and modelling study

The aim of this study was to investigate the effects of two different irrigation strategies, regulated deficit irrigation, RDI and partial root drying, PRD using surface freshwater (SW) and brackish treated wastewater (TWW) for maize and potato crops. The SALTMED model has been applied using the field measurements of two cropping seasons 2013 and 2014 at the Canale Emiliano Romagnolo, CER’s experimental farm located in Mezzolara di Budrio (Bologna, Italy). In 2013, PRD irrigated potato received 17% less irrigation water than RDI but produced nearly the same yield as under RDI. The water productivity, o naverage, was 11% higher for PRD compared with RDI. For maize 2014 season, the PRD strategy received almost 15% less irrigation water, but produced a yield only 6% lower than that of RDI and gave equal water productivity to RDI. Given that the two strategies received the same amount of rainfall the results favour the PRD over RDI. Had the site not received above average rainfall (258 mm in 2013 and 259 mm during the 2014 growing seasons), PRD might have produced higher yield and water productivity than RDI. In terms of model simulations, overall, the model showed a strong relationship between the observed and the simulated soil moisture and salinity profiles, total dry mater and final yields. This illustrates SALTMED model’s ability to simulate the dry matter and yield of C3 and C4 crops as well as to simulated different water qualities and different water application strategies. Therefore, the model can run with “what if” scenarios depicting several water qualities, crops and irrigation systems and strategies without the need to try them all in the field. This will reduce costs of labour and investment

Effect of exogenous salicylic acid on growth parameters, gas exchange, and photosynthetic yields in salt-stressed Vicia faba l. plants

This study aimed to evaluate the potential effect of salicylic acid (SA) on the photosynthetic performance of faba bean (Vicia faba L.) plants under salt stress conditions. For this purpose, two salinity levels (0 and 120 mM) combined with two concentrations of SA (0 and 0.5 mM) were applied. Results showed that salt stress decreases the growth and gas exchange parameters (P-N, C-i, g(s), and T-r). Chlorophyll fluorescence imaging parameters showed a decrease in the effective photochemical quantum yield of PSII (YPII), photochemical quenching (qP), and electron transport rate (ETR), while the regulated (Y(NPQ) and unregulated dissipation energy Y(NO)) were increased under stress conditions. However, exogenous SA application under salt stress decreases the non-regulated dissipation and improves photosynthetic performance (Y(PSII), ETR, qP, and Y(NPQ)), growth, and gas exchange parameters. Consequently, SA application had a beneficial effect on the faba bean tolerance to salt stress and can be recommended for field application with low concentration.info:eu-repo/semantics/publishedVersio

Combined effect of salicylic acid and calcium application on salt-stressed strawberry plants

The salinity of water and agricultural lands is a major environmental factor adversely affecting crop productivity. Strawberry plants have been found to be sensitive to salt stress conditions. Salicylic acid (SA) and Ca2+ are endogenous signal molecules involved in many metabolic processes, which can stimulate the plants defence mechanisms to biotic and abiotic constraints. The main objective of this work was to investigate the impacts of SA (0.25 mM) and calcium nitrate (5 mM) application, singly or in combination, on growth parameters as well as physiological and biochemical markers of strawberry plants (Fragaria ananassa Duch, var. Fortuna) exposed to saline conditions (80 mM NaCl). The results showed that high salinity reduces plant growth and photosynthetic pigment content. Salt stress also induced an accumulation of Na, a decrease in K and Ca concentrations, a reduction in the levels of sugars, total phenol, relative water content, photochemical efficiency (F-v/F-m), and stomatal conductance as well as a decrease in proline, proteins, enzyme activities (catalase, superoxide dismutase and peroxidase) and an accumulation of hydrogen peroxide and malondialdehyde. However, SA and calcium treatments enhanced the plants' tolerance to salt stress by improving the above-mentioned parameters. Additionally, the best results were obtained with combined treatment (Ca + SA) under both salinity conditions. These findings indicated that the combination of calcium supplementation with exogenous application of SA may provide an effective solution to improving the strawberry plant's tolerance to saline conditions.info:eu-repo/semantics/publishedVersio