Soil salinity is a major problem in arid and semi-arid regions, causing land degradation, desertification, and subsequently, food insecurity. Salt-affected soils and phosphorus (P) deficiency are the common problems in the sub-Sahara, including the Southern region of Morocco. Soil salinity limits plant growth by limiting water availability, causing a nutritional imbalance, and imparting osmotic stress in the plants. The objective of this study was to determine the positive effects of P on growth and productivity and understand the major leaf mineral nutrient content of quinoa (Chenopodium quinoa Willd.) cv. “ICBA Q5” irrigated with saline water. A field experiment applying three salinity (Electrical Conductivity, EC) levels of irrigation water (ECw = 5, 12, and 17 dS·m⁻¹) and three P fertilizer rates (0, 60, and 70 kg of P₂O₅ ha⁻¹) were evaluated in a split-plot design with three replications. The experiment was conducted in Foum El Oued, South of Morocco on sandy loam soil during the period of March–July 2020. The results showed that irrigation with saline water significantly reduced the final dry biomass, seed yield, harvest index, and crop water productivity of quinoa; however, P application under saline conditions minimized the effect of salinity and improved the yield. The application of 60 and 70 kg of P₂O₅ ha⁻¹ increased (p < 0.05) the seed yield by 29 and 51% at low salinity (5 dS·m⁻¹), by 16 and 2% at medium salinity (12 dS·m⁻¹), and by 13 and 8% at high salinity (17 dS·m⁻¹), respectively. The leaf Na⁺ and K⁺ content and Na⁺/K⁺ ratio increased with irrigation water salinity. However, the leaf content of Mg, Ca, Zn, and Fe decreased under high salinity. It was also found that increasing P fertilization improved the essential nutrient content and nutrient uptake. Our finding suggests that P application minimizes the adverse effects of high soil salinity and can be adopted as a coping strategy under saline conditions.

Salinity is a major problem affecting agriculture in many regions of the world, including Morocco. The best agronomic practices such as fertilization are used to cope with salinity stress and improve productivity under saline conditions. The objective of this study is to evaluate the interactive effect of phosphorus and salinity on sugar beet (Beta vulgaris L.) cv. “Sporta” productivity and quality. A field experiment was carried out, testing three levels of irrigation water salinity (ECw = 0.7; 4, 8, and 12 dS·m⁻¹) and three levels of phosphorus (100, 120, and 140 kg P₂O₅·ha⁻¹) organized in a split-plot design with three replicates. This research was conducted in the Tadla region (center of Morocco) during two seasons in 2019 and 2020. The obtained results show that irrigation water salinity had a negative effect on most growth and productivity parameters. For instance, sugar beet yield reduced by 21% and by 26% under saline irrigation, with an EC value equal to 4 and 8 dS·m⁻¹, respectively, compared to the control during the 2018–2019 season, and by 1%, 19%, and 27% under saline irrigation, with an EC value equal to 4 and 8 and 12 dS·m⁻¹, respectively compared to the control (0.7 dS·m⁻¹) during the 2019–2020 season. Total sugar content was significantly increased by 5% and 7%, respectively, under saline irrigation, with an EC value of 4 and 8 dS·m⁻¹, respectively, as compared with the control in the first growing season in 2018–2019. However, in the second growing season (2019–2020), only the highest level of saline water (EC = 12 dS·m⁻¹) significantly increased in sugar content by 15% compared to the control. Regarding the P fertilization effect, it was found that a P rate of 120 kg P₂O₅·ha⁻¹ was enough to improve the yield and sugar content of sugar beet under the tested salinity levels. Thus, P fertilization could be one of the best practices to enhance sugar beets’ tolerance of salinity. To obtain a maximum root and sugar yield under saline water, it is recommended to apply a phosphorus dose of 120 kg P₂O₅·ha⁻¹.

Salinity is a major problem affecting crop production in many regions in the world including Morocco. Agricultural practices such as fertilization could be useful to overcome this problem and improve crop productivity. The objective of our study was to evaluate the combined effect of phosphorus fertilization and irrigation water salinity on growth, yield, and stomatal conductance of forage corn (Zea mays L.) cv. “Sy sincerro”. Field experiments were carried out for two years testing four levels of irrigation water salinity (ECw = 0.7; 2, 4, and 6 dS·m⁻¹) and three rates of phosphorus (105, 126, and 150 kg P₂O₅·ha⁻¹) fertilization conducted in a split-plot design with three replications. The obtained results show that irrigation water salinity had a negative effect on all monitored parameters. For instance, the dry matter yield reduced by an average of 19.3 and 25.1% compared to the control under saline irrigation with an EC value equal to 4 and 6 dS·m⁻¹, respectively. The finding also showed that phosphorus applications tend to increase root weight, root length, stem length, leaf stomatal conductance, grain yield and dry matter yield under salinity conditions. For example, the addition of phosphorus with a rate of 126 and 150 kg P₂O₅·ha⁻¹ respectively improved dry matter yield by an average of 4 and 9% under low salinity level (ECw = 2 dS·m⁻¹), by 4 and 15% under medium salinity (4 dS·m⁻¹), and by 6 and 8% under a high salinity level (6 dS·m⁻¹). Our finding suggests that supplementary P application could be one of the best practices to reduce the adverse effects of high salinity on growth and development of forage corn.

High soil salinity, drought, and poor soil fertility, especially phosphorus (P) deficiency, are serious challenges for crop production in arid and desert climate regions. In these regions, irrigation water (mostly groundwater) is saline, and fertilization is one of the strategies used to cope with salinity stress. Crop livestock is one of the major agricultural activities in marginal regions, and blue panicum (Panicum antidotale Retz.), the perennial forage grass, has the potential to furnish forage demand. Thus, a field experiment testing the combination of three levels of irrigation water salinity and three P rate was carried out to evaluate the potential of P fertilizer to enhance yield and salinity tolerance of blue panicum grass. The experiment was conducted for two years between 2019 and 2020 in Foum el Oued, Laayoune, Morocco. It was implemented in a split-plot design with three replications considering irrigation water salinity as the main plot and P rates as sub-plot treatments. The evaluated P rates were 0, 90, and 108 kg P₂O₅ ha⁻¹ (P1, P2, and P3, respectively), and the irrigation water salinities were 5, 12, and 17 dS·m⁻¹. The results revealed that increasing irrigation water salinity significantly decreased the biomass production and stomatal conductance of blue panicum. Increasing irrigation water salinity from 5 to 12 and 17 dS·m⁻¹ decreased fresh biomass production by 20 and 29%, respectively. Irrigation water salinity also decreased (p < 0.05) leaf N, P, K, Ca, and Zn concentration. However, supplementation of P fertilization enhanced (p < 0.05) biomass production and stomatal conductance mainly by improving leaf OM, Zn, and Fe content. P fertilization at 108 kg P₂O₅ ha⁻¹ increased fresh biomass by 27%, 32%, and 19% under 5, 12, and 17 dS·m⁻¹, respectively. Considering increased fresh biomass yield, P application at the rate of 108 kg P₂O₅ ha⁻¹ can be suggested for saline drylands. P application is recommended to reduce the adverse effects of high salinity on growth and productivity and improve salinity tolerance of blue panicum in salt-affected arid and desert regions.

In regions facing water scarcity and soil salinity, mitigating these abiotic stresses is paramount for sustaining crop production. This study aimed to unravel the synergistic effects of organic matter and phosphorus management in reducing the adverse effect of saline water for irrigation on red pepper (Capsicum annuum L.) production, fruit quality, plant physiology, and stress tolerance indicators. The study was carried out in the arid Tadla region of Morocco and involved two key experiments: (i) a field experiment during the 2019 growing season, where red pepper plants were subjected to varying phosphorus fertilizer rates (120, 140, and 170 kg of P₂O₅.ha⁻¹) and saline water irrigation levels (0.7; 1.5; 3; and 5 dS.m⁻¹); and (ii) a controlled pot experiment in 2021 for examining the interaction of saline water irrigation levels (EC values of 0.7, 2, 5, and 9 dS.m⁻¹), phosphorus rates (30, 36, and 42 kg of P₂O₅.ha⁻¹), and the amount of organic matter (4, 8, 12, and 16 t.ha⁻¹). The field study highlighted that saline irrigation significantly affected red pepper yields and fruit size, although phosphorus fertilization helped enhance productivity. Additionally, biochemical markers of stress tolerance, such as proline and glycine betaine, along with stomatal conductance, were impacted by increasing salinity levels. The pot experiment showed that combining organic amendments and phosphorus improved soil properties and stimulated red pepper growth and root weight across all salinity levels. The integration of phosphorus fertilization and organic amendments proved instrumental for counteracting salinity-induced constraints on red pepper growth and yield. Nonetheless, caution is necessary as high salinity can still negatively impact red pepper productivity, necessitating the establishment of an irrigation water salinity threshold, set at 5 dS.m⁻¹.