Sulfur deficiency arising due to intensive cultivation, use of sulfur free fertilizers and reduction in atmospheric sulfur depositions has become a major issue limiting crop production in many parts of the world. Elemental sulfur could be a good source of available S, but its slow oxidation is a problem for its efficient use as a sulfur fertilizer. Main objective of the study was to assess the effect of organic amendments (OA) and elemental sulfur (ES) on microbial activities, sulfur oxidation and availability in soil. A laboratory incubation experiment was carried out for a 56 days period using two sulfur deficient alkaline soils. Organic amendments (OA), i.e., farmyard manure (FYM), poultry litter (PL) and sugarcane filter cake (SF), were applied (1% w/w) with or without elemental sulfur (ES) at 50 mg kg⁻¹. Application of ES alone or in combination with OA significantly increasedCO₂-C evolution, microbial biomass, and enzyme activities in the soils, except dehydrogenase activity (DHA) which was not affected by ES application. Combined application of OA and ES had a more pronounced effect on microbial parameters compared to ES or OA applied alone. Ratios of dehydrogenase activity-to-microbial biomass C and arylsulfatase activity-to-microbial biomass C were high in ES+FYM and ES+SF treatments, respectively. Elemental sulfur got sufficiently oxidized resulting in significant improvement in plant available S. Relatively more ES was distributed into C-bonded-S than ester bonded-S. Increase in sulfur availability in ES+OA amended soils was the combined function of sulfur oxidation and mineralization processes through improved microbial activity.

Drought is a major constraint in drylands for crop production. Plant associated microbes can help plants in acquisition of soil nutrients to enhance productivity in stressful conditions. The current study was designed to illuminate the effectiveness of desert rhizobacterial strains on growth and net-return of chickpeas grown in pots by using sandy loam soil of Thal Pakistan desert. A total of 125 rhizobacterial strains were isolated, out of which 72 strains were inoculated with chickpeas in the growth chamber for 75 days to screen most efficient isolates. Amongst all, six bacterial strains (two rhizobia and four plant growth promoting rhizobacterial strains) significantly enhanced nodulation and shoot-root length as compared to other treatments. These promising strains were morphologically and biochemically characterized and identified through 16sRNA sequencing. Then, eight consortia of the identified isolates were formulated to evaluate the growth and development of chickpea at three moisture levels (55%, 75% and 95% of field capacity) in a glass house experiment. The trend for best performing consortia in terms of growth and development of chickpea remained T₂ at moisture level 1 > T₇ at moisture level 2 > T₄ at moisture level 3. The present study indicates the vital role of co-inoculated bacterial strains in growth enhancement of chickpea under low moisture availability. It is concluded from the results that the consortium T₂ (Mesorhizobium ciceri RZ-11 + Bacillus subtilis RP-01 + Bacillus mojavensis RS-14) can perform best in drought conditions (55% field capacity) and T₄ (Mesorhizobium ciceri RZ-11 + Enterobacter Cloacae RP-08 + Providencia vermicola RS-15) can be adopted in irrigated areas (95% field capacity) for maximum productivity of chickpea.

Dryland crop production is restraining due to severe effects of drought spells and natively derived resilient isolates can support crop yield enhancement under abiotic stress. This study elaborated for isolation, morpho-physiological, biochemical characterization and molecular identification of indigenous soil microbes from Thal desert of Pakistan and their application to elucidate the efficacy of desert isolates on yield of chickpeas growing on three farmer fields (Kakri, Adhi Kot and Jara) of native area. Isolates were identified through 16sRNA sequencing and used to formulate eight consortia with different combination. Four isolates (Bacillus subtilis RP-01, Enterobacter Cloacae RP-08, Bacillus mojavensis RS-14 and Providencia vermicola RS-15) have ability to produce indole-3-acetic acid (IAA), Protease, catalase, ACC-deaminase and EPS, among, the two strains RP-01 and RP-08 were found phosphate solubilizer and others two isolates Mesorhizobium ciceri RZ-11 and Mesorhizobium ciceri RZ-22 were appeared as ammonia producing. The consortia in T7 showed highest grain yield (1201 kg ha-1) followed by T2 (1126 kg ha-1) at same location (Kakri) comparatively to other consortia and control (557 kg ha-1). Similarly, T2 found most promising consortia regarding grain yield (1072.1 kg ha-1 and 961.8 kg ha-1) at locations Adhi Kot and Jara, respectively during the 1st year. However, T4 also performed with par to T2 and T7 consortium and same trend was seen in the next year field experiments. The present study confirmed that T2 (Mesorhizobium ciceri RZ-11 + Bacillus subtilis RP-01 + Bacillus mojavensis RS-14), T4 (Mesorhizobium ciceri RZ-11 + Enterobacter cloacae RP-08 + Providencia vermicola RS-15) and T7 (Mesorhizobium ciceri RZ-22 + Enterobacter cloacae RP-08 + Providencia vermicola RS-15) are promising consortia for chickpeas yield in Thal desert of Punjab, Pakistan.