Worldwide crop productivity hampers severely due to the adverse effects of salinity. Global warming causes a rapid escalation of the salt-affected area, and new agricultural land is affected through saltwater intrusion. The ever-growing human population impulses to utilize the saline area for crop cultivation to ensure food security. Salinity resistance crops could be a promising substitute but with minor success because inappropriate tactics on saline soil management resulted in unsatisfactory yield. Salt-tolerant plant growth-promoting rhizobacteria (ST-PGPR) is considered an alternate way towards enhancing crop growth in saline ecosystems. It is reported that PGPR is enabled to produce exopolysaccharides which lead to biofilm formation and generate osmoprotectants and antioxidant enzymes that can significantly contribute to stimulating plant growth in the saline ecosystem. In addition, several plant growth-promoting characteristics of PGPR such as the acquisition of essential nutrients and upsurge hormone production could enhance plant growth simultaneously. In this review, we will explore the survival mechanisms of ST-PGPR and their influence on plant growth promotion in saline ecosystems.

Decomposed organic materials, in combination with plant growth-promoting bacteria (PGPB), are environmentally friendly and reduce synthetic fertilizer use in rice production. A bio-organic fertilizer (BoF) was prepared using kitchen waste (79%), chita-dhan (unfilled rice grain) biochar (15%), rock phosphate (5%), and a consortium of 10 PGPB (1%) to supplement 30% nitrogen and to replace triple superphosphate (TSP) fertilizer in rice production with an improvement of soil health. PGPB were local isolates and identified using 16S ribosomal RNA partial gene sequences asBacillus mycoides,Proteussp.,Bacillus cereus, Bacillus subtilis, Bacillus pumilus, Paenibacillus polymyxa, andPaenibacillusspp. Isolates could fix N₂by 0.7–1.4 g kg^–1, solubilize 0.1–1.2 g kg^–1phosphate, and produce 0.1–40 g kg^–1indoleacetic acid. The performance of BoF was evaluated by 16 field experiments and 18 farmers’ field demonstration trials during the year 2017–2020 in different parts of Bangladesh. Performances of BoF were evaluated based on control (T₁), full synthetic fertilizer dose of N, P, and K (T₂), BoF (2 t ha^–1) + 70% N as urea + 100% K as muriate of potash (T₃), 70% N as urea + 100% P as TSP + 100% K as muriate of potash (T₄), and 2 t ha^–1BoF (T₅) treatments. At the research station, average grain yield improved by 10–13% in T₃compared with T₂treatment. Depending on seasons, higher agronomic N use efficiency (19–30%), physiological N use efficiency (8–18%), partial factor productivity (PFP)_N(114–150%), recovery efficiency (RE)_N(3–31%), N harvest index (HI_N) (14–24%), agronomic P use efficiency (22–25%), partial factor productivity of P (9–12%), ARE_P(15–23%), and HI_P(3–6%) were obtained in T₃compared with T₂treatment. Research results were reflected in farmers’ field, and significant (P< 0.05) higher plant height, tiller, panicle, grain yield, partial factor productivity of N and P were obtained in the same treatment. Application of BoF improved soil organic carbon by 6–13%, along with an increased number of PGPB as compared with full synthetic fertilizer dose. In conclusion, tested BoF can be considered as a green technology to reduce 30% synthetic N and 100% TSP requirements in rice production with improved soil health.

A study was conducted to assess the effects of organic amendments on soil aggregates, carbon (C) sequestration, and energy use efficiency (EUE) during five consecutive Boro and Transplanted Aman rice seasons in Bangladesh during 2018–2020. Five treatments (viz., control (only inorganic fertilizers), cow dung (CD), vermicompost (VC), rice straw (RS), and poultry manure (PM)) were used. The organic materials were applied at 2 t C ha⁻¹ season⁻¹ to all the plots, except in the control treatment. Inorganic fertilizers were applied in all treatments in both seasons following integrated nutrient management (INM). The data reveal that PM was found to be more efficient at increasing the water-stable soil aggregates (WSA), followed by the RS, CD, and VC. The WSA in smaller-sized soil aggregates were found to be higher than those in larger-sized soil aggregates. VC was found to be the most effective in terms of C sequestration (29%), followed by PM (26%), CD (22%), and RS (20%). The highest EUE was attributed to the control treatment (9.77), followed by the CD (8.67), VC (8.04), RS (2.10), and PM (1.18), which showed energy wastage in the organic treatments. The system productivity (SP) followed the opposite trend of the EUE. The INM is a better approach to improve the soil health, the C sequestration, and the SP, but it appeared as an energy-inefficient strategy, which suggests that a balanced application of organic and inorganic nutrients is needed in order to achieve yield sustainability and EUE.

A study was conducted to determine the efficacy of applying ground magnesium limestone (GML) or ground basalt in combination with bio-fertilizer to sustain rice production on an acid sulfate soil in Malaysia. Soils from Kelantan Plains, Malaysia, were treated with GML, ground basalt, bio-fertilizer, GML + bio-fertilizer, and ground basalt + bio-fertilizer (4 t·ha⁻¹ each). Results showed that soil fertility was improved by applying the soil amendments. GML and basalt contain some Zn and Cu; thus, application of these amendments would increase their contents in the soil needed for the healthy growth of rice. Basalt applied in combination with bio-fertilizer appeared to be the best agronomic option to improve the fertility of acid sulfate soils for sustainable rice production in the long run. In addition to increasing Ca, Mg, Zn, and Cu reserves in the soil, water pH increased and precipitated Al³⁺ and/or Fe²⁺. Ground basalt is cheaper than GML, but basalt dissolution in the acidic soil was slow. As such, its ameliorative effects could only be seen significantly from the second season onwards. The specially-formulated bio-fertilizer for alleviating the infertility of acid sulfate soil could also enhance rice growth. The use of the bio-fertilizer fortified with N₂-fixing bacteria is a green technology that would help reduce NO₃⁻ and/or NO₂⁻ pollution and reduce the cost of rice production. The phosphate-solubilizing bacteria (PSB) present in the bio-fertilizer not only increased the available P, but also helped release organic acids that would inactivate Al³⁺ and/or Fe²⁺ via the process of chelation.

A study was conducted to evaluate the effects of applying rice husk biochar (RHB) or ground magnesium limestone (GML) in combination with bio-fertilizer on soil biochemical properties and the yield of rice planted on an acid sulfate soil. The RHB or GML plus bio-fertilizer were applied each at the rate of 4 t ha⁻¹. Applying the amendments increased soil pH (>5.0) and improved soil biochemical properties with a concomitant reduction of Al and Fe that resulted in enhanced rice growth. Applying GML plus bio-fertilizer resulted in increased soil N content (0.20%), available P (34.38 mg kg⁻¹), exchangeable Ca (2.97 cmol_c kg⁻¹) and exchangeable Mg (2.45 cmol_c kg⁻¹); all these enhanced rice nutrient uptake. The highest bacterial population of 8.34 log₁₀ CFU g⁻¹ soil was found in the same treatment. Applying GML and RHB alone, or in combination with bio-fertilizer, was found to enhance rice growth and the yield. The highest plant height (90.33 cm), leaf chlorophyll content (38.05), plant tiller numbers (16), filled grains (86%), number of panicles per plant (18), lengths of panicles (24.40 cm), grain (5.24 t ha⁻¹), straw yield (10.20 t ha⁻¹) and harvest index (0.51) were determined in the GML plus bio-fertilizer, followed by RHB plus bio-fertilizer treatment. Thus, GML applied in combination with bio-fertilizer is considered as a promising agronomic package to sustain the production of rice planted on acid sulfate soils.

Modern rice cultivation relies on chemical nitrogen (N) fertilizer that ultimately degrades soil health and creates environmental pollution. The increasing concerns about environmental pollution, restoring soil health, and conservation of energy, public attention is now towards green manures as supplement for N fertilizer. Sesbania rostrata is a popular leguminous green manuring crop that fixes atmospheric N₂, improves soil health, and rice productivity through incorporation of its biomass in to soil. About 40–60 days plants provide 5–6 tons dry biomass that can supplement 50–100% N requirement. In world, it is adapted as pre-rice or post-rice green manuring crop. Long-term use of S. rostrata improves soil health and increased rice yield by 9–11% over chemical fertilizer. Use of S. rostrata in large scale for rice production can reduce environmental pollution problems as it can cut down chemical N requirement and thus reduction dispersal of Nr to the environment.