Heavy metals (HM) in agricultural soils are a significant threat to crop productivity, adversely affecting plant growth and development through various physiological and biochemical mechanisms. Among the HM, nickel (Ni) has been reported to be increasingly accumulated in the soil and is a serious threat to human health via the food chain. Poor seedlings growth and low-quality produce are major causes of Ni toxicity in plants. The current study aimed to assess the effect of activated pomegranate peel biochar (APPB) on morpho-physiological and biochemical processes of wheat grown in Ni-affected soil. Different treatments i.e. control, biochar, Ni, and biochar + Ni were designed under randomized complete block design with six replications of each treatment. The morphological, biochemical, and physiological responses were then evaluated. Present results revealed the growth decline in wheat seedlings subjected to Ni toxicity. Moreover, disturbances in photosynthetic pigments, metabolites, and thiol group were recorded in seedlings under excess of Ni content. The findings of this study demonstrate that the application of APPB supplementation significantly alleviated the negative effect of Ni on wheat seedlings and improved growth parameters by 171%, 83%, 330%, 78%, and 96% in shoot biomass, shoot length, root biomass, root length, and seedlings dry weight, respectively. Chlorophyll a, b, and total chlorophyll contents boosted by 44%, 83%, and 55%. Carbohydrate content also increased by 82%, while total phenols and flavonoids were reduced by 24% and 22%, respectively. The stunted growth and irregular photosynthesis were recorded in wheat seedlings due to nickel toxicity. Hence, APPB proved to be an effectives soil amendment, that may be used for improved crop growth with enhanced and increasing tolerance to metal stress through the modulation of defense indices.

The relationships between soil aggregates, aggregate-associated carbon (C), and soil compaction indices in pomegranate orchards of varying ages (0-30 years) in Assiut, Egypt, were investigated. Soil bulk density (Bd) and organic carbon (OC) content increased with orchard age in both the surface (0.00-0.20 m) and subsurface (0.20-0.40 m) layers 0.20-0.40 m). The percentage of macroaggregates (R-0.25) and their OC content in the aggregate fraction > 0.250 mm increased as the pomegranate orchard ages increased in the surface layer (0.00-0.20 m). Older pomegranate orchards show improved soil structure, indicated by higher mean weight diameter (MWD) and geometric mean diameter (GMD), alongside reduced fractal dimension (D) and erodibility (K). As orchard ages increased, maximum bulk density (BMax) decreased due to an increase in OC, while the degree of compactness (DC) increased, reaching a maximum at both soil layers for the 30 Y orchards. Soil organic carbon and aggregate-associated C significantly influenced BMax, which led to reducing the soil compaction risk. Multivariate analyses identified the >2 mm aggregate fraction as the most critical factor influencing the DC, soil compaction, and K indices in pomegranate orchards. The OC content in the >2 mm aggregates negatively correlated with BMax, DC, and K but was positively associated with MWD and GMD. Moreover, DC and Bd decreased with higher proportions of >2 mm aggregates, whereas DC increased with a higher fraction of 2-0.250 mm aggregation. These findings highlight the role of aggregate size fractions and their associated C in enhancing soil structure stability, mitigating compaction, and reducing erosion risks in pomegranate orchards.

This study investigates the prevalence and dynamics of pomegranate wilt disease induced by Meloidogyne incognita across the Kullu, Mandi and Solan districts of Himachal Pradesh (India), revealed notable spatial and temporal variations in nematode populations and galling severity across the regions. The highest average nematode infestation of 9.25 % was observed at Nauni with highest counts of average second-stage juvenile (J2) larvae (449 larvae per 100 cc of soil) followed by Hurla (Kullu) with 7.42 % infestation. Correlation analysis reveals a strong positive relationship between larval population and galling severity suggesting a potential link between nematode levels and plant damage. Common disease symptoms were leaf size reduction, yellowing and gradual decline of pomegranate plants, often observed in patches within orchards. Microscopic identification revealed distinctive pear-shaped body of mature females while J2 larvae displayed vermiform shapes and the associated species of M. incognita was confirmed through examination of the perineal pattern. Pathogenicity test reveals initiation of leaf yellowing symptom after 45 days of inoculation of larval suspension and root galling was observed after 60 days onward followed by plant decline under greenhouse conditions. Results from pot and field experiments demonstrated the efficacy of Fluopyram and Fluensulfone in reducing nematode populations and galling severity. Treatment with drenching of Fluopyram at the rate of 2 ml/L reduced 98.56 % larvae under field and 99.00 % larvae/100 cc soil under pot conditions. Statistical analysis (paired t-test and MANOVA) confirms significant differences in galling severity and larval population before and after drenching. The study also underscores the importance of weed management in disease mitigation as several weed species (Chenopodium album and Solanum nigrum) were identified as potential reservoirs for M. incognita in infested pomegranate plant basin. This investigation contributes to the advancement of management practices for pomegranate cultivation that addresses both nematode and weed infestations ultimately enhancing crop resilience and productivity.