Role of Arbuscular Mycorrhizal Fungi and Phosphate Solubilizing Bacteria in Improving Yield, Yield Components, and Nutrients Uptake of Barley under Salinity Soil

Barley (Hordeum vulgare, L.) is the fourth most important cereal crop in the world. Salinity decreases the productivity of plants grown under salinity conditions. It leads to deficiency and limited absorption of water and nutrients, ionic stress, oxidative stress, and osmotic imbalance. In saline soil, a field experiment was conducted to verify the effects of nine combinations among three levels of bio-fertilizers, i.e., control (without), arbuscular mycorrhizal fungi (AMF), and phosphate solubilizing bacteria (PSB), as well as three levels of phosphorus fertilizer recommended dose (RDP) on barley yield, its components and nutrients uptake, to evaluate the useful influences of these combinations to improve P management under salinity stress related to yield and its components as well as N, P, and K uptake in barley. Findings revealed that the combination AMF + 100% RDP improved plant height, length of spike, spikes weight, number of spikes plant−1, weight of 1000-grain, straw yield, grain yield, uptake of nitrogen (N), phosphorus (P), potassium (K) in grain and uptake of nitrogen (N), phosphorus (P), potassium (K) in straw by 19.76, 33.21, 40.08, 33.76, 14.82, 24.95, 47.52, 104.54, 213.47, 168.24, 124.30, 183.59, and 160.84% in the first season, respectively. Meanwhile, the increase was 19.86, 29.73, 40.47, 39.94, 14.92, 24.95, 47.94, 104.73, 213.33, 168.64, 124.47, 183.86, and 161.09% in the second season, respectively. AMF showed greater efficiency and effectiveness compared to PSB in improving yield and its components for all studied traits. The results of principle component analysis indicated that all combinations except AMF + zero% RDP, PSB + zero% RDP, control + zero% RDP, and control + 66% RDP showed high scores on positive PC1, where all studied traits were high. Therefore, it is recommended to inoculate the soil with AMF or PSB with the addition of phosphate fertilizer at the recommended dose under salinity conditions, i.e., AMF + 100% RDP (T1) or AMF + 66% RDP (T2) or PSB + 100% RDP (T4). The use of bio-fertilizers has increased plant tolerance to salt stress, and this was evident from the increase in different traits with the use of treatments that include bio-fertilizers.