Salinity stress is one of the serious restrictive issues for optimum crop production in arid to semi-arid areas. Application of organic amendments have shown positive effects on crop growth and yield under such scenario. The present study was conducted to estimate the potential of calcium-fortified composted animal manure (Ca-FCM) to enhance growth and yield of canola under saline soil conditions. Salt affected soils with various electrical conductivity (EC) levels (original 1.5, 5, and 10 dS m⁻¹) were developed via spiking the soil with sodium chloride (NaCl) salt. The results reveal that soil salinity reduced the growth, physiological, yield, and nutritional parameters of canola. However, application of 3% calcium-fortified composted manure significantly enhanced the growth and yield parameters at all EC levels as compared to control. Plant physiological parameters such as photosynthetic rate, relative chlorophyll contents (SPAD value), and relative water content were also increased with the application of 3% Ca-FCM at all EC levels in comparison to control. Application of 3% Ca-FCM also mediated the antioxidant enzymes activities at all EC levels in comparison to control. Moreover, application of 3% Ca-FCM caused maximum increase in nitrogen, phosphorus, and potassium concentrations in shoot at all EC levels. Conversely, application of 3% Ca-FCM showed maximum decrease in Na⁺/K⁺ ratio in leaf up to 83.33%, 77.78%, and 71.43% at EC levels 1.5, 5, and 10 dS m⁻¹, respectively, as compared to control. It was concluded that application of calcium-fortified composted animal manure (Ca-FCM) could be an efficient method for improving growth, yield, physiological, and nutritional parameters of canola through mediation of antioxidant defense machinery under saline soil conditions.

Soil salinity and sodicity are among the main problems for optimum crop production in areas where rainfall is not enough for leaching of salts out of the rooting zone. Application of organic and Ca-based amendments have the potential to increase crop yield and productivity under saline–alkaline soil environments. Based on this hypothesis, the present study was conducted to evaluate the potential of compost, Ca-based fertilizer industry waste (Ca-FW), and Ca-fortified compost (Ca-FC) to increase growth and yield of maize under saline–sodic soil conditions. Saline–sodic soil conditions with electrical conductivity (EC) levels (1.6, 5, and 10 dS m⁻¹) and sodium adsorption ratio (SAR) = 15, were developed by spiking soil with a solution containing NaCl, Na₂SO₄, MgSO₄, and CaCl₂. Results showed that soil salinity and sodicity significantly reduced plant growth, yield, physiological, and nutrient uptake parameters. However, the application of Ca-FC caused a remarkable increase in the studied parameters of maize at EC levels of 1.6, 5, and 10 dS m⁻¹ as compared to the control. In addition, Ca-FC caused the maximum decrease in Na⁺/K⁺ ratio in shoot up to 85.1%, 71.79%, and 70.37% at EC levels of 1.6, 5, and 10 dS m⁻¹, respectively as compared to the control treatment. Moreover, nutrient uptake (NPK) was also significantly increased with the application of Ca-FC under normal as well as saline–sodic soil conditions. It is thus inferred that the application of Ca-FC could be an effective amendment to enhance growth, yield, physiology, and nutrient uptake in maize under saline–sodic soil conditions constituting the novelty of this work.

In the present study, we investigated the impact of different combinations of wheat straw biochar, compost and biogas slurry on maize growth, physiology, and nutritional status in less productive soils. The experiment was performed as a completely randomized block design in a greenhouse pot experiment. The compost and biogas slurry were applied with and without biochar. The results revealed that a combination of biochar, compost, and biogas slurry enhanced the cation exchange capacity (31%), carbon (83%), phosphorus (67%) and potassium (81%) contents in the soil. Likewise, a significant increase in soil microbial biomass carbon (15%) and nitrogen (37%) was noticed with the combined use of all organic amendments. Moreover, the combined application of biochar, compost and biogas slurry enhanced soil urease and β-glucosidase activity up to 96% and 67% over control respectively. In addition, plant height, chlorophyll content, water use efficiency and 1000-grain weight were also enhanced up to 54%, 90%, 53% and 21% respectively, with the combined use of all amendments. Here, biochar addition helped to reduce the nutrient losses of compost and biogas slurry as well. It is concluded that biochar application in combination with compost and biogas slurry could be a more sustainable, environment-friendly and cost-effective approach, particularly for less fertile soils.

Water scarcity is abiotic stress that is becoming more prevalent as a result of human activities, posing a threat to agriculture and food security. Recently, endophytic bacteria have been proven to reduce drought stress and increase crop productivity. Here, we explored the efficacy of seed endophytic bacteria in maize crops under water deficit conditions. For this purpose, twenty-seven endophytic bacteria have been isolated from three distinct maize cultivars seeds (Malka 2016, Sahiwal Gold and Gohar-19) and evaluated for desiccation tolerance of −0.18, −0.491, and −1.025 MPa induced by polyethylene glycol (PEG) 6000. The nine isolates were chosen on the basis of desiccation tolerance and evaluated for maize growth promotion and antioxidant activity under normal and drought conditions. Results showed that drought stress significantly decreased the growth of maize seedlings. However, isolates SM1, SM4, SM19, and SM23 significantly improved the root and shoot length, plant biomass, leaf area, proline content, sugar, and protein content under normal and drought conditions. Antioxidant enzymes were significantly decreased at p-value < 0.05 with inoculation of seed endophytic bacteria under drought conditions. However, further experiments of seed endophytic bacteria (SM1, SM4, SM19, and SM23) should be conducted to validate results.

Iron-biofortification is a sustainable food-based approach to combat iron deficiency by increasing iron content and bioavailability in agronomic crops. Siderophore producing microbes offer a sustainable and low-cost way to increase iron supply in crops. Also, certain substances released from organic amendments act as iron-chelators which increase the solubility as well as the availability of iron to plants. Present study investigated the role of siderophore-producing endophytic bacteria and biochar on iron-fortification of a novel crop quinoa in iron-limited saline conditions. The surface-disinfected seeds of quinoa were inoculated with Burkholderia phytofirmans PsJN (CFU = 10⁹) and sown in saline soil (EC 20 dS m⁻¹) amended with biochar (1% w/w). Results revealed that biochar and PsJN particularly when applied together significantly enhanced plant growth, grain yield, and grain nutrient contents of quinoa. Strikingly, iron concentration in quinoa grains was increased up to 71% by the combined application of biochar and PsJN. Moreover, plant physiological parameters were also improved significantly by the integrated application. However, enzymatic/non-enzymatic antioxidants activities were decreased by integrated treatment thus ameliorated salinity stress. Our study suggests that integrated application of siderophore-producing bacteria and biochar could be a promising, sustainable and cost-effective strategy which is easily integratable into the existing farming practices to achieve food fortification with micronutrients in developing countries.

Low bioavailability of phosphorus (P) in alkaline/calcareous soils leads to low yields due to its precipitation/fixation with calcium (Ca). An effective method to enhance phosphorus use efficiency (PUE) and its availability to plants is the application of alginate bioaugmented coated di-ammonium phosphate (DAP). In this study, the pre-isolated P solubilizing Paraburkholderia phytofirmans (PsJN) coated with different concentrations of polymer (alginate) on DAP with and without carbon source was tested in incubation, pot, and field experiments to investigate microbial survival, Olsen P release, and its availability to plants. Results indicated that the maximum recovery of PsJN loaded on alginate at 30 days incubation with and without carbon source was 199 × 10¹⁰ and 82 × 10⁶ CFU mL⁻¹ respectively. Application of alginate bioaugmented DAP released 962 mg kg⁻¹ Olsen P after 60 days of incubation compared to 280 and 370 mg kg⁻¹ Olsen P released by uncoated and simple alginate coated DAP, respectively. Results from pot trial revealed that application of 100% alginate bioaugmented DAP increased 26% plant height, 31% photosynthetic rate, 55% grain yield, and 6 × 10⁵ CFU g⁻¹ root bacterial population, compared to uncoated DAP. Field trial results indicated that 22% grain yield, 14% straw yield, and 44% agronomy P efficiency were increased by applying 100% alginate bioaugmented DAP compared to uncoated DAP. This new approach resulted in controlled release of P from coated DAP that not only reduced phosphorus fixation but also enhanced the bioavailability of P to plants.