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Flood events around the globe have severely impaired the soil functioning resulting in compromised food security in several parts of the world. The current study was aimed to explore the impacts of floods on soil heavy metals and nutrients status at three locations; Tibbi Solgi (TS), Vinri Khosa (VK), and Noshehra West (NW-control) in the district Rajanpur of Punjab, Pakistan. TS and VK sites were under regular influence of flooding over the last many years, but no flood event was reported on NW site during the same tenure; hence, it served as control. Sampling was carried out before and after flooding on the experimental sites. Vegetation cover was monitored through remote sensing techniques. Results revealed varying effects of floods on soil heavy metals; Cd, Cr, Pb, and soil phosphorous and nitrates. Flood events increased the Cd while lowered Pb concentration at VK site; however, flooding did not influence the status of Cr in soil. Similar to the trend observed in case of Cd, soil phosphorous and nitrates were reduced after flood events. Correlation analyses of soil physicochemical properties with soil heavy metals and nutrients indicated that after flood events, soil texture and organic carbon content seem to be the major factors driving the shift in soil heavy metals and nutrient concentrations. Although pollution indices indicated a marginally low contamination levels, but as projected in empirical studies, regular flood events in the studied sites may contaminate the whole ecosystem rendering it unfit for agricultural productivity. [ABSTRACT FROM AUTHOR]

Land use has a greater influence on the contamination of soils. The current research is conducted to study the effect of different land-use patterns and soil depth on heavy metal fractions in the soil. Significant differences among heavy metals (Cd, Cu, Fe, Ni, Pb, and Zn) in soils under various land use systems were observed. Variations in the soil heavy metals concentration were found dependent on land use patterns. Irrespective of the type of metal, Land uses differed for heavy metals concentrations in the order of fallow>pasture>crop>forest soils. Extracting reagents considerably varied for the concentrations of metals: HNO3>Na2EDTA>NaOH>KNO3>H2O. However, Ni concentration was found higher with NaOH than Na2EDTA. Surface soil indicated a higher magnitude of heavy metals than sub-surface soil. This study will provide valuable information on heavy metal fractions associated with land use in the Abbottabad region of lesser Himalayas, Pakistan. [ABSTRACT FROM AUTHOR]

Terrestrial ecosystems are under the enormous pressure of land use management regimes through human disturbances, resulting in the disruption of biogeochemical cycles and associated ecosystem services. Nitrogen (N) in soil ecosystems is of vital importance for primary productivity, hence estimating the extent of these human interventions on N-cycling processes becomes imperative from economic and environmental perspectives. This work investigated the impacts of variable anthropogenic activities on N cycling in three different terrestrial ecosystems (arable, grassland, and forest) in three regions of lower Himalaya, Pakistan. Potential nitrification (PNA) and denitrification (DEA) enzyme activities, relative distribution of inorganic N species (NH 4 , NO 3 ), and the role of inherent edaphic factors were assessed. Results revealed high nitrification potentials and increased nitrous oxide (N 2 O) emissions in the incubated soil microcosms, in the order as arable > grassland > forest ecosystems. Notably, higher rates of both studied processes (~ 30-50%) and elevated soil mineral nitrogen pool were observed in arable ecosystems. Forest soils, assumed as pristine ecosystems relying mainly on natural N fixation, produced (de)nitrification rates relatively lower than grasslands, followed by arable soils which were moderately disturbed through long-term fertilization and intensive land-use regimes. Linear regression modeling revealed that the inorganic N species (particularly NO 3 ), and inherent edaphic factors were the key determinants of high (de)nitrification rates, hence warn of accelerated N losses in these ecosystems. The study highlights that elevated PNA and DEA being proxies for the altered N cycling in the studied terrestrial ecosystems are of great ecological relevance in view of predicted N 2 O budget in the lower Himalaya., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)