Muhammad Farooq Qayyum

Soil salinity is a significant challenge in agriculture, particularly in arid and semi-arid regions such as Pakistan, leading to soil degradation and reduced crop yields. The present study assessed the impact of different salinity levels (0, 25, and 50 mmol NaCl) and biochar treatments (control, wheat-straw biochar, rice-husk biochar, and sawdust biochar applied @ 1% w/w) on the germination and growth performance of wheat. Two experiments: a germination study and a pot experiment (grown up to maturity), were performed. The results showed that NaCl-stress negatively impacted the germination parameters, grain, and straw yield, and agronomic and soil parameters. Biochar treatments restored these parameters compared to control (no biochar), but the effects were inconsistent across NaCl levels. Among the different biochars, wheat-straw biochar performed better than rice-husk and sawdust-derived biochar regarding germination and agronomic parameters. Biochar application notably increased soil pH_s and electrical conductivity (EC_e). Imposing NaCl stress reduced K concentrations in the wheat shoot and grains with concomitant higher Na concentrations in both parts. Parameters like foliar chlorophyll content (a, b, and total), stomatal and sub-stomatal conductance, and transpiration rate were also positively influenced by biochar addition. The study confirmed that biochar, particularly wheat-straw biochar, effectively mitigated the adverse effects of soil salinity, enhancing both soil quality and wheat growth. The study highlighted that biochar application can minimize the negative effects of salinity stress on wheat. Specifically, the types and dosages of biochar have to be optimized for different salinity levels under field conditions.

This study evaluates the potential of sewage sludge, farm manure, rock phosphate, and their composts or biochar as useful materials for phosphorous (P) recovery. An alkaline–calcareous soil was incubated with different compost-based amendments to discern their impact on the P sorption characteristics. The treatments examined consisted of sewage sludge (SS), SS biochar (SS-BC), or composts of SS with rock phosphate (RP) and farm manure (FM) in different ratios, i.e., (i) control, (ii) SS, (iii) SS-BC, (iv) SS₅₀:FM₅₀, (v) SS₇₅:FM₂₅, (vi) SS₂₅:FM₂₅:RP₅₀, (vii) SS₅₀:FM₂₅:RP₂₅, (viii) SS₇₅:FM₀:RP₂₅, and (ix) SS₅₀:FM₀:RP₅₀. Prior to incubation for 45 days, the composts and biochar treatments combinations were characterized for elemental composition using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) spectroscopy. The treated soils were analyzed for soil pH, electrical conductivity (EC), Olsen’s P, and P adsorption isotherms, at day 5 and 45 of the incubation. Langmuir and Freundlich’s equations were used to calculate P adsorption. Results showed that there was no significant influence on soil pH for any treatment throughout the experiment. However, soil EC decreased significantly for all treatments after 5 days of incubation; however, this effect was diminished after 45 days of incubation. All the treatments significantly decreased P sorption capacity both at the start (day 5) and end of the incubation (day 45) period compared to control. The treatment combination SS₂₅:FM₂₅:RP₅₀ recovered the highest Olsen-P (79.41 mg kg⁻¹). The other treatment combinations including SS and FM also recovered a greater Olsen’s P compared to the control. However, the sole application of only SS showed lower P recovery than the control soil, which further decreased with increase in incubation time. These findings improve our understanding that the stable pool of bioavailable P within an alkaline calcareous soil can be mobilized by using different organic treatment combinations instead of only SS. However, further in situ investigations may help to valorize the potential of sewage sludge, farm manure, rock phosphate, and their composts or biochar to improve P recovery in alkaline–calcareous.

Recently nanoparticles (NPs) are ubiquitous in the environment because they have unique characteristics which are the reason of their wide use in various fields. The release of NPs into various environmental compartments mainly ends up in the soil through water bodies which is a serious threat to living things especially plants. When present in soil, NPs may cause toxicity in plants which increase significance to minimize NPs stress in plants. Although gibberellic acid (GA) is one of the phytohormones that has the potential to alleviate abiotic/biotic stresses in crops plant, GA-mediated alleviation of cerium oxide (CeO₂) NPs in plants is still unknown, despite the large-scale application of CeO₂-NPs in various fields. The present study was performed to highlight the ability of foliar-applied GA in reducing CeO₂-NPs toxicity in wheat under soil exposure of CeO₂-NPs. We observed that CeO₂-NPs alone adversely affected the dry weights, chlorophyll contents, and nutrients and caused oxidative stress in plants, thereby reducing plant yield. GA coupled with CeO₂-NPs reversed the changes caused by CeO₂-NPs alone as indicated by the increase in plant growth, chlorophylls, nutrients, and yield. Furthermore, GA alleviated the oxidative stress in plants by enhancing antioxidant enzyme activities under CeO₂-NPs exposure than the NPs alone which further provided the evidence of reduction in oxidative damage in plants by GA. Overall, evaluating the potential of GA in reducing CeO₂-NPs toxicity in wheat could provide important information for improving food safety under CeO₂-NPs exposure.

Cadmium (Cd) availability in arable soils is a serious issue while little is known about the role of co-composted organic amendments and zinc oxide nanoparticles (ZnO-NPs) foliar spray on biomass and Cd accumulation in wheat grains. The current study investigated the soil application of organic amendment (composted biochar and farmyard manure) at a level of 0, 1, and 2% w/w and foliar spray of ZnO-NPs (0, 100, and 200 mg/L) on biomass, yield, and Cd in wheat grains cultivated in an aged Cd-contaminated agricultural soil. The results indicated that organic amendment increased the biomass, chlorophyll concentrations, yield, and activities of peroxidase and superoxide dismutase of wheat while decreased the electrolyte leakage and Cd concentrations in different parts of wheat such as shoots, roots, husks, and grains. This effect of organic amendment was further enhanced by the foliar spray of ZnO-NPs in a dose-additive manner. Cadmium concentration in grains was below threshold level (0.2 mg/kg DW) for cereals in combined application of 200 mg/L ZnO-NPs and 1% organic amendment as well as in higher treatment (2%) of organic amendment and NPs. Thus, combined use of organic materials and NPs might be a suitable way of reducing Cd and probably other toxic trace element concentrations in wheat and other cereals.