Salinity impedes soil and crop productivity in over 900 million ha of arable lands worldwide due to the excessive accumulation of salt (NaCl). To utilize saline soils in agriculture, halophytes (salt-tolerant plants) are commonly cultivated. However, most food crops are glycophytes (salt-sensitive). Thus, to enhance the productivity of saline soils, gypsum (CaSO₄·2H₂O) as well as bio-organic (combined use of organic materials, such as compost and straw with the inoculation of beneficial microbes) amendments have been continuously recognized to improve the biological, physical and chemical properties of saline soils. CaSO₄·2H₂O regulates the exchange of sodium (Na⁺) for calcium (Ca²⁺) on the clay surfaces, thereby increasing the Ca²⁺/Na⁺ ratio in the soil solution. Intracellularly, Ca²⁺ also promotes a higher K⁺/Na⁺ ratio. Simultaneously, gypsum furnishes crops with sulfur (S) for enhanced growth and yield through the increased production of phytohormones, amino acids, glutathione and osmoprotectants, which are vital elicitors in plants’ responses to salinity stress. Likewise, bio-organic amendments improve the organic matter and carbon content, nutrient cycling, porosity, water holding capacity, soil enzyme activities and biodiversity in saline soils. Overall, the integrated application of gypsum and bio-organic amendments in cultivating glycophytes and halophytes is a highly promising strategy in enhancing the productivity of saline soils.

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This study aimed to evaluate the efficiency ofEnterobacter cloacaePS14 andTrichoderma asperellumT34 in the control of potato wilt, caused byRalstonia solanacearum(Smith), under greenhouse and field conditions. In vitro, the endophyteE.cloacaePS14 caused the highest reduction of the pathogen growth among 7 screened bacteria. It produced an inhibition zone as 16.9 mm compared to a specific antibiotic (20.0 mm).E.cloacaePS14 was selected as an effective antagonistic bacterium to be compared toT.asperellumstrain T34 for reduction of the disease as well as increasing the crop yield of potato plants. BothE.cloacaeandT.asperellumreduced the disease severity up to 10.7–26.5%, respectively, under greenhouse and up to 26.6–36.6%, respectively, under field conditions. The results approved that bothE.cloacaeandT.asperellumincreased the yield of the crop by 20.44–40.96%, respectively. Their mode of action was indicated by suppression of the pathogen as well as induction of plant systemic resistance. The induction of systemic resistance was confirmed by increasing the total phenol and salicylic acid contents as well as increasing the activities of peroxidase, lipoxygenase, and polyphenol oxidase in potato plants than the healthy or only infected plants. Production of siderophore, indole-3-acetic acid (0.577–0.884 μM), hydrogen cyanide (2.34–3.61 μg/ml), and salicylic acid (0.436–1.488 μg/ml) was confirmed by E. cloacae PS14 andT.asperellumT34, respectively, in vitro. The study recommends the new strainE.cloacaePS14, as new endophytic effective bacteria, in the control ofR.solanacearumcausing the potato wilt disease.