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Cadmium (Cd) contamination in the soil potentially hampers microbial biomass and adversely affects their services such as decomposition and mineralization of organic matter. It can reduce nitrogen (N) metabolism and consequently affect plant growth and physiology. Further, Cd accumulation in plants can pose health risks through vegetable consumption. Here, we investigated consequences of Cd contamination on fertilizer value and associated health risks following the application of biogas residues (BGR) to various soil types. Our results indicate that the application of BGR to all soil types significantly increased dry matter (DM) yield and N uptake. However, the Cd contamination negatively affected DM yield and N recovery from BGR in a dose-dependent manner. Organic N mineralization from BGR also decreased in Cd-contaminated soils. The highest DM yield and N recovery were recorded in sandy soil, whereas the lowest values were observed in clay soil. Cadmium was accumulated in spinach, and health risk index (HRI) associated with its dietary intake revealed that consuming spinach grown in Cd-contaminated soil, with or without BGR, is unsafe. Among the soil types, values of daily intake of metals (DIM) and HRI were lowest in clay soil and highest in sandy soil. However, the application of BGR curtailed HRI across all soil types. Notably, the application of BGR alone resulted in HRI values < 1, which are under the safe limit. We conclude that soil contamination with Cd reduces fertilizer value and entails implications for human health. However, the application of BGR to the soil can decrease Cd effects.

Coronavirus disease (COVID)-19 is a viral and transferable disease caused by severe respiratory syndrome-coronavirus-2. It can spread through breathing droplets in human beings. It caused 5.32 million deaths around the world at the end of 2021. COVID-19 has caused several positive impacts as well, such as a reduction in air, water, and noise pollution. However, its negative impacts are by far critical such as increased death rate, increased release of microcontaminants (pesticides, biocides, pharmaceuticals, surfactants, polycyclic aromatic hydrocarbons (PAHs), flame retardants, and heavy metals), increased biomedical waste generation due to excessive use of safety equipment and its disposal, and municipal solid waste generation. Environmental pollution was significantly reduced due to lockdown during the COVID-19 period. Therefore, the quality of air and water improved. COVID-19 affected all sections of the population, particularly the most vulnerable members of society, and thus pushed more people into poverty. At the world level, it increased risks to food safety by increasing prices and lowering revenues, forcing households to reduce their food consumption in terms of quantity and quality. COVID-19 also upset various exercises e.g., horticulture, fisheries, domesticated animals, and agribusiness hence prohibiting the development of merchandise for poor-country ranchers. Most of the patients can self-recover from COVID-19 if they do not have any other diseases like high blood pressure, diabetes, and heart problems. Predictably, the appropriate execution of the proposed approaches (vaccination, wearing face masks, social distancing, sustainable industrialization) is helpful for worldwide environmental sustainability., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Lithium (Li) is the lightest alkali metal and 27th most abundant element in the earth crust. In traces, the element has medicinal value for various disorders in humans, however, its higher concentrations may lead to treatment-resistant depression and altered thyroid functioning. Quinoa (Chenopodium quinoa) has gained popularity owing to its halophytic nature and its potential use as an alternative to the traditional staple foods. However, quinoa response to Li-salt in terms of growth, Li accumulation potential and health risks associated with consumption of the quinoa seeds grown on Li-contaminated soils has not been explored yet. During this study, quinoa was exposed to various concentrations of Li (0, 2, 4, 8 and 16 mM) at germination as well as seedling stages. The results showed that seed germination was the highest (64% higher than control) at Li concentration of 8 mM. Similarly, at 8 mM doses of Li shoot length, shoot dry weight, root length, root dry weight and grain yield were increased by 130%, 300%, 244%, 858% and 185% than control. It was also revealed that Li increased the accumulation of calcium and sodium in quinoa shoots. Carotenoids contents were increased, but chlorophyll contents remained un-changed under Li application. The activities of antioxidants viz. Peroxide dismutase, catalase and super oxide dismutase were also increased with an increase in the levels of Li in the soil. Estimated daily intake and hazard quotient of Li in quinoa were less than the threshold level. It was concluded that Li concentration of 8 mM is useful for quinoa growth and it can be successfully grown on Li contaminated soils without causing any human health risks., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Climatic conditions significantly affect the maize productivity. Among abiotic factors, nitrogen (N) fertilizer and temperature are the two important factors which dominantly affect the maize ( Zea mays L.) production during the early crop growth stages. Two experiments were conducted to determine the impact of N fertilizer and temperature on the maize growth and yield. In the first experiment, the maize hybrids were screened for their sensitivity to temperature variations. The screening was based on the growth performance of the hybrids under three temperatures ( T 1 = ambient open-air temperature, T 2 = 1°C higher than the ambient temperature, and T 3 = 1°C lower than the ambient temperature) range. The results showed that an increase in temperature was resulted less 50% emergence and mean emergence (4.1 and 6.3 days, respectively), while emergence energy and full emergence were higher (25.4 and 75.2%, respectively) under the higher temperature exposure. The results showed that Syngenta 7720 and Muqabla S 25W87 were temperature tolerant and sensitive maize hybrids, respectively. The second experiment was carried out to study the response of the two selected maize hybrids (Syngenta 7720 and Muqabla S 25W87) to four N fertilizer applications. The results revealed that the maximum N use efficiency (19.5 kg kg -1 ) was achieved in maize hybrids with low N application (75 kg N ha -1 equivalent to 1.13 g N plant -1 ). However, the maximum maize grain yield (86.4 g plant -1 ), dry weight (203 g plant -1 ), and grain protein content (15.0%) were observed in maize hybrids that were grown with the application of 300 kg N ha -1 (equivalent to 4.52 g N plant -1 ). Therefore, it is recommended that the application of 300 kg N ha -1 to temperature tolerant maize hybrid may be considered best agricultural management practices for obtaining optimum maize grain yield under present changing climate., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hammad, Chawla, Jawad, Alhuqail, Bakhat, Farhad, Khan, Mubeen, Shah, Liu, Harrison, Saud and Fahad.)

Zinc (Zn) plays an important role in the physiology and biochemistry of plants due to its established essentiality and toxicity for living beings at certain Zn concentration i.e., deficient or toxic over the optimum range. Being a vital cofactor of important enzymes, Zn participates in plant metabolic processes therefore, alters the biophysicochemical processes mediated by Zn-related enzymes/proteins. Excess Zn can provoke oxidative damage by enhancing the levels of reactive radicals. Hence, it is imperative to monitor Zn levels and associated biophysicochemical roles, essential or toxic, in the soil-plant interactions. This data-analysis review has critically summarized the recent literature of (i) Zn mobility/phytoavailability in soil (ii) molecular understanding of Zn phytouptake, (iii) uptake and distribution in the plants, (iv) essential roles in plants, (v) phyto-deficiency and phytotoxicity, (vi) detoxification processes to scavenge Zn phytotoxicity inside plants, and (vii) associated health hazards. The review especially compares the essential, deficient and toxic roles of Zn in biophysicochemical and detoxification processes inside the plants. To conclude, this review recommends some Zn-related research perspectives. Overall, this review reveals a thorough representation of Zn bio-geo-physicochemical interactions in soil-plant system using recent data., Competing Interests: Declaration of competing interest Authors declare no known conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The widespread use of nano-enabled agrochemicals in agriculture for remediating soil and improving nutrient use efficiency of organic and chemical fertilizers is increasing continuously with limited understanding on their potential risks. Recent studies suggested that nanoparticles (NPs) are harmful to soil organisms and their stimulated nutrient cycling in agriculture. However, their toxic effects under natural input farming systems are just at its infancy. Here, we aimed to examine the harmful effects of nano-agrochemical zinc oxide (ZnONPs) to poultry (PM) and farmyard manure (FYM) C and N cycling in soil-plant systems. These manures enhanced microbial counts, CO 2 emission, N mineralization, spinach yield and N recovery than control (unfertilized). Soil applied ZnONPs increased labile Zn in microbial biomass, conferring its consumption and thereby reduced the colony-forming bacterial and fungal units. Such effects resulted in decreasing CO 2 emitted from PM and FYM by 39 and 43%, respectively. Further, mineralization of organic N was reduced from FYM by 32%, and PM by 26%. This process has considerably decreased the soil mineral N content from both manure types and thereby spinach yield and plant N recoveries. In the ZnONPs amended soil, only about 23% of the applied total N from FYM and 31% from PM was ended up in plants, whereas the respective fractions in the absence of ZnONPs were 33 and 53%. Hence, toxicity of ZnONPs should be taken into account when recommending its use in agriculture for enhancing nutrient utilization efficiency of fertilizers or soil remediation purposes., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Aims: The present research aimed to examine the use of magnetite nanoparticles (MNPs) in combination with phyto-beneficial rhizobacterium (PhBR) for improvement of applied N recovery (ANR) from urea fertilizer in rice grown under deficient and optimum watering conditions., Methods and Results: The Bacillus sp. MR-1/2 was positive for acetylene reduction, phosphate solubilization and ACC deaminase activity at temperature ranges 35-45°C. In a pot experiment, urea, MNPs and Bacillus sp. MR-1/2 were applied either alone or in combination to rice plants grown in pots under water deficit and optimal watering conditions. Combined application of urea, MNPs and Bacillus sp. MR-1/2 increased the plant N content and ANR by 27 and 65%, respectively, over their respective control values in rice grown under optimum watering conditions, whereas these increases were 27 and 41%, respectively, in rice grown under water deficit conditions. This treatment also increased the kernel weight and plant dry matter by 36 and 60%, respectively, over control (urea alone) values in rice grown under water deficit conditions, whereas these increases were 31 and 21·8%, respectively, in rice grown under optimum watering conditions. Values of malondialdehyde (MDA) contents, ascorbate peroxidase (APX), catalase and ethylene concentration were higher in control treatment under both the watering regimes. The application of Bacillus sp. MR-1/2 either alone or in combination with MNPs and urea reduced MDA contents, APX, catalase and ethylene production in the rice plants., Conclusion: The combined application of MNPs+Bacillus sp. MR-1/2 reduced the N losses from applied urea, increased N uptake and ANR in rice, decreased MDA contents, APX and catalase activity and ethylene level in rice grown under deficit and optimum water conditions., Significance and Impact of the Study: The application of MNPs together with Bacillus sp. MR-1/2 may help to increase ANR and rice productivity under water deficit conditions with low cost of production., (© 2021 The Society for Applied Microbiology.)

Silicon (Si)-mediated growth promotion of various grasses is well documented. In the present study, Si-induced changes in maize shoot growth and its underlying mechanisms were studied. Maize plants were grown with various concentrations of Si (0-3 mM) in the nutrient solution. Silicon nutrition improved plant expansion growth. Silicon-supplied maize plants (0.8 and 1.2 mM) showed higher plant height and leaf area compared to no-Si amended plants. It was assumed that Si-induced expansion growth was due to positive Si effects on plasma membrane (PM) H + -ATPase. In this context, western blot analysis revealed an increase in PM H + -ATPase abundance by 77% under Si nutrition. However, in vitro measurements of enzyme activities showed no significant effect on apoplast pH, proton pumping, passive H + efflux and enzyme kinetics such as K m , V max , and activation energy. Further, these results were confirmed by in vivo ratiometric analysis of apoplastic pH, which showed non-significant changes upon Si supply. In contrast, 1 mM Si altered the relative transcripts of specific PM H + -ATPase isoforms. Silicon application resulted in a significant decrease of MHA3, and this decrease in transcription seems to be compensated by an increased concentration of H + -ATPase protein. From these results, it can be concluded that changes in cell wall composition and PM H + -ATPase may be responsible for Si-mediated growth improvement in maize., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Soil contamination with metallic nanoparticles is increasing due to their increased use in industrial and domestic settings. These nanoparticles are potentially toxic to soil microbes and may affect their associated functions and thereby the nutrient cycling in agro-ecosystems. This study examined the effects of iron oxides nanoparticles (IONPs) on carbon (C) and nitrogen (N) dynamics of poultry (PM) and farmyard manure (FYM) in the soil. The application of IONPs increased iron content in soil microbial biomass, which reflected its consumption by the microbes. As a result, colony-forming units of bacteria and fungi reduced considerably. Such observations lead to a decrease in CO 2 emission from PM and FYM by 27 and 28%, respectively. The respective decrease fractions in the case of N mineralization were 24 and 35%. Consequently, soil mineral N content was reduced by 16% from PM and 12% from FYM as compared to their sole application without IONPs. Spinach dry matter yield and apparent N recovery were increased by the use of organic waste (FYM, PM). The use of IONPs significantly reduced the plant N recovery fraction by 26 and 24% (P < 0.05) from PM and FYM, respectively. All the results mentioned above lead us to conclude that IONPs are toxic to soil microbes and affect their function i.e., carbon and N mineralization of applied manure, and thereby the on-farm N cycling from the manure-soil-plant continuum., (Copyright © 2020 Elsevier Inc. All rights reserved.)

In peri-urban areas of district Vehari, farmers are using untreated city wastewater for crop irrigation owing to the scarcity of good-quality irrigation water. This practice may pose severe environmental and health issues to local inhabitants attributed to the high levels of potentially toxic metals in wastewater. The present study evaluated the potential impacts of wastewater irrigation on metals (Cd, Cr, Cu, Fe, Ni, Mn, Pb and Zn) build-up in the soil-plant continuum and associated health risks. In this study, wastewater (n = 17), soil (n = 108) and plant (n = 65) samples were collected from 15 peri-urban sites of three tehsils of district Vehari. Results showed that the mean concentration (mg/L) of Cd (0.02), Mn (0.25) and Fe (1.57) in wastewater samples was higher than their respective threshold values. Similarly, Cd, Mn and Fe concentration in soil was beyond the permissible limits of agricultural soil receiving wastewater irrigation. However, plants showed high accumulation of Pb, Cr and Fe than their respective limits depending on the vegetable/crop species. The health risk parameters showed that Pb and Cd are the major toxic chemical substances to human health, and the daily intake of crop plants can pose a potential health threat due to wastewater-irrigated crop consumption. Results highlighted the necessity of wastewater pretreatment to avoid the soil and vegetable contamination by wastewater irrigation and to reduce the associated health risks.

Climate change is occurring and is influencing biological systems through augmented temperatures, more inconstant precipitation, and rising CO 2 in the atmosphere. For sustainable landscaping, it was essential to assess the diversity of native/wild grasses and their suitability for turf and to combat the salinity problem in the region. For this purpose, a native halophytic grass, Aeluropus lagopoides, was investigated by conducting mowing tests on its ecotypes during the year 2014-2016 under desert climatic conditions. The research was carried out in two phases, i.e. Phase-I was for collection and establishment of ecotypes from various parts of UAE, while in Phase-II, mowing tests were conducted. During mowing tests, 50 ecotypes of A. lagopoides were given various mowing treatments (i.e. they were cut back at 1-, 2-, 3-, 4- and 5-cm heights) in field conditions. Significant differences were found among various ecotypes for different agronomic parameters such as ground cover, canopy stiffness, leaf number, clippings fresh and dry weights and internode length. Overall, the grass exhibited better performance at mowing heights of 3 and 4 cm, which are the standard mowing heights for turfgrasses. Ecotypes FA5, RA3, RUDA2, RUDA7 and RUADA1 of A. lagopoides showed the best performance against mowing shock and became the candidates for the turfgrass varieties from the native Arabian flora.

Lithium (Li) exploitation for industrial and domestic use is resulting in a buildup of the element in various environmental components that results in potential toxicity to living systems. Therefore, a soil culture experiment was conducted to evaluate the effects of increasing concentration of Li (0, 20, 40, 60, and 80 mg kg -1 soil) on spinach growth, the effects of Li uptake, and its effects on various physiological attributes of the crop. The results showed that lower levels of Li in soil (20 mg Li kg -1 ) improve the growth of spinach plants, while a higher concentration of applied Li enhanced the pigment contents. Higher concentrations of Li in soil interfered with potassium and calcium uptake in plants. Moreover, increasing Li concentration resulted in higher activities of antioxidant enzymes activity in spinach shoots. From these results, it is concluded that spinach shoot accumulated higher concentrations of Li without showing any visual toxicity symptoms. Therefore, the study concludes that Li ion was mostly deposited in leaves rather than in roots which may cause potential human health risk on the consumption of Li-contaminated plants. Therefore, the cultivation of leafy vegetables in Li-affected soils should be avoided to reduce the potential human health risks.

Literature related to the carbon cycle and climate contains contradictory results with regard to whether agricultural practices increase or mitigate emission of greenhouse gases (GHGs). One opinion is that anthropogenic activities have distinct carbon footprints - measured as total emissions of GHGs resulting from an activity, in this case, "agricultural operations". In contrast, it is argued that agriculture potentially serves to mitigate GHGs emissions when the best management practices are implemented. We review the literature on agricultural carbon footprints in the context of agricultural practices including soil, water and nutrient management. It has been reported that the management practices that enhance soil organic carbon (SOC) in arid and semi-arid areas include conversion of conventional tillage practices to conservation tillage approaches. We found that agricultural management in arid and semi-arid regions, which have specific characteristics related to high temperatures and low rainfall conditions, requires different practices for maintenance and restoration of SOC and for control of soil erosion compared to those used in Mediterranean, tropical regions. We recommend that in order to meet the global climate targets, quantification of net global warming potential of agricultural practices requires precise estimates of local, regional and global carbon budgets. We have conducted and present a case study for observing the development of deep soil carbon profile resulting from a 10-year wheat-cotton and wheat-maize rotation on semi-arid lands. Results showed that no tillage with mulch application had 14% (37.2 vs 43.3 Mg ha -1 ) higher SOC stocks in comparison to conventional tillage with mulch application. By implementing no tillage in conjunction with mulch application, lower carbon losses from soil can mitigate the risks associated with global warming. Therefore, it is necessary to reconsider agricultural practices and soil erosion after a land-use change when calculating global carbon footprints., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interests regarding the publication of this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Soils contain one of the largest carbon (C) pools in the biosphere with the greatest potential of C sequestration to mitigate climate change impacts. The present study aimed at comparing C sequestration potential of various land use systems including forestlands, croplands, agroforests, and orchards in the arid region of Pakistan. Soil samples from the layers of 0-20, 20-40, 40-60, and 60-80 cm depths were collected and analysed for soil physico-chemical properties namely texture, pH, EC, NPK-soil, organic matter (SOM), and soil organic C (SOC). Additionally, the above and below ground plant biomass and C contents were estimated. Results revealed that the highest C sequestration potential (64.54 Mg ha -1 ) was in the above ground biomass of forest land and the lowest (33.50 Mg ha -1 ) in cropland. The below ground plant biomass at 0-20 cm soil depth was 14.09, 12.38, 11.78, 11.76, and 10.92 Mg ha -1 for forest land, mango orchards, agroforests, citrus orchards and cropland, respectively. The respective values in case of total C content were, 6.84, 6.79, 6.10, 5.69 Mg ha -1 . Irrespective to the soil depth, below ground biomass and total C followed the order: forest land > mango orchard > citrus orchard > agroforests > crop lands. It is concluded that the forest land have greater potential for C sequestration than the other land use systems studied in the arid region of Pakistan. Therefore, in order to cope up with climate change disasters in Pakistan the massive reforestation project - named the Billion Tree Tsunami of the Government of Pakistan will prove beneficial., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interests regarding the publication of this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Arsenic (As) is a highly toxic and carcinogenic element. It has received considerable consideration worldwide in recent years due to its highest toxicity to human, and currently, high concentrations observed in the groundwater. Some recent media and research reports also highlighted possible As contamination of groundwater systems in Pakistan. However, there is a scarcity of data about As contents in groundwater in different areas/regions of the country. Consequently, the current study estimated the As concentration in the groundwater used for drinking purpose in 15 peri-urban sites of district Vehari, Pakistan. In total, 127 groundwater samples were collected and examined for As contents in addition to physicochemical characteristics such as temperature, electrical conductivity, pH, total soluble salts, chloride, carbonates, bicarbonates, sodium, potassium, lithium, calcium and barium. Results indicated that the groundwater samples were not fully fit for drinking purposes with several parameters, especially the alarming levels of As (mean As: 46.9 µg/L). It was found that 83% groundwater samples of peri-urban sites in district Vehari have As concentration greater than WHO lower permissible limit (10 µg/L). The risk assessment parameters (mean hazard quotient: 3.9 and mean cancer risk: 0.0018) also showed possible carcinogenic and non-carcinogenic risks associated with ingestion of As-contaminated groundwater at peri-urban sites. Based on the findings, it is anticipated that special monitoring and management of groundwater is necessary in the studied area in order to curtail the health risks associated with the use of As-contaminated drinking water. Moreover, appropriate remediation and removal of As from groundwater is also imperative for the study area before being used for drinking purpose to avoid As exposure and related risks to the local community.

Picotechnology development in vast disciplines is mainly attributed to the research and development (R and D) on nanotechnology. Being a parent technology, nanotechnology is the cornerstone of picotechnology. Like nanotechnology, the reference standard for picotechnology is nature, the cellular and subcellular functioning. Some studies have highlighted that the functional margin of similar type of molecules at picoscale (10 -12 ) goes higher than at nanoscale (10 -9 ). In this review, the potential applications of picotechnology have been evaluated especially in the disciplines of biomedical and environmental sciences. Extended surface area and improved electrical, chemical, optical, and mechanical properties make picotechnological products even better than nanomaterials. The fundamental objective of this study is to bring the attention of the scientific world towards the picoscale interventions and to highlight the wide scope of picotechnology as a newly emerging technology with applications in numerous sectors. Picotechnology has made it possible to measure very small structure in advance biomedical and environmental sciences studies. Adequate developments in picotechnology will certainly change human lives in near future because it will make possible for the research world to dive into systems and structures on picoscale. It will render a platform through which explorers can travel into ultra-small areas, which will lead to the creation of new dimensions as well as new opportunities. Eventually, in future, the picotechnology will become smaller enough to give birth to femtotechnology (10 -15 ) in real-world applications.

Road traffic accidents (RTAs) are among the life-threatening issues facing rural as well as sub-/urban communities. Several factors contribute to RTAs ranging from human to technical and natural/environmental impacts. Anthropogenic air pollution and corresponding environmental factors also increase the probability of RTAs. Current study reports the relationship of the weather conditions to RTAs. The study establishes the relevancy of different weather conditions like rainfall, temperature, fog, and wind storm with the incidences of RTAs in rural and urban settings of Vehari, Punjab-Pakistan. The results of the study showed that rainfall, severe coldness, fog, and heat conditions were directly related with the occurrence of RTAs. The percentage of RTAs which occurred due to fog, rainfall, temperature, and other weather-related factors was 34, 25, 21, and 20%, respectively. The age of the driver significantly correlated (R 2  = 0.60) with RTAs; the drivers in the age group 40-60 years caused the least RTAs during their drive. Since the smaller vehicles were involved in maximum RTAs, it relates negatively (R 2  = 0.82) to vehicles power. Among different vehicles motor bikes were involved in most (42%) of the reported RTAs. Therefore, during severe weather conditions, vehicles with smaller size and young drivers must be dealt with carefully while interacting (crossing, overtaking, and maneuvering) on the roads regardless of rural or urban conditions. Factors including civic sense, traffic education, vehicle size, drivers' maturity, road conditions, and environmental impacts may be considered while designing traffic rules and traffic aware campaigns specific for developing countries such as Pakistan.

Reutilization of putrescible municipal solid wastes (MSW) in agriculture can provide valuable plant nutrients. However, it may pose serious noncarcinogenic health risks for a human when contaminants, especially the heavy metals in MSW, end up in plants through the waste-soil-plant continuum. This study examined the effects of composting methods viz. aerobically (AC), anaerobically (ANC), and aerobic-anaerobically (AANC) composted MSW material on (i) fertilizer value: vegetable yield, nitrogen (N) mineralization, and apparent N recovery (ANR); and (ii) associated health risks: selected heavy metal concentration, daily intake of metals (DIM), health risk index (HRI), hazard index (HI), and target hazard quotient (THQ) when applied to a loamy soil. All the aforementioned compost materials were incorporated into the sandy loam soil filled in pots and carrot and spinach were cultivated for 85 and 90 days, respectively. After soil application, between 51 and 56% of the applied organic N was mineralized from ANC material, while the values in case of AC and AANC were 26-31% and 34-40%, respectively. Consequently, dry matter yield and vegetable N uptake from composts were in the order ANC > AANC > AC (P < 0.05). Further, vegetable ANR was the highest from ANC (56 and 56%) than AANC (42 and 45%), and AC (30 and 33%) for spinach and carrot, respectively (P < 0.05). Interestingly, plant uptake of lead and cadmium was lowest from ANC as compared to AC or AANC (P < 0.05), irrespective of the vegetable type. Consequently, DIM, HRI, and THQ for these metals were substantially lower in the former as compared to the latter compost materials. Further, HI from ANC material was 50% lower over the unfertilized control indicating the absence of noncarcinogenic human health risks via vegetable intake. This all indicates that from viewpoint of sustainable waste recycling in agriculture, anaerobic composting is superior to the other composting methods.

Soil contamination with heavy metals is a global issue confronting the environmental pollution and human/animal health. Much work has been done on physiological and antioxidant responses of wheat in hydroponic experiments and health risks from individual heavy metal contamination to human, but limited information is available on their combined application in soil. Therefore, this pot study delineates the uptake of lead and cadmium, as well as physiological responses of wheat and associated health risks under different levels of alone and combined Cd and Pb treatments. Metal uptake increased with their increasing applied levels. The highest Cd (4.24, 1.38, and 0.92 mg kg -1 ) and Pb (763.33, 39.63, and 16.35 mg kg -1 ) concentrations in root, shoot, and grain, respectively, were observed at highest applied levels (0.4 mM Cd and 10 mM Pb). Furthermore, all the treatments increased lipid peroxidation and activities of superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase, while decreased total chlorophyll contents and membrane stability index. Under combined application of Cd and Pb, the toxicity and detoxification responses of wheat increased compared to alone treatments. Multivariate analysis further confirmed the toxicity and accumulation pattern of metals under alone and combined treatments. Target hazard quotient values of Cd and Pb were < 1 under alone and combined treatments. The health hazard index values of Pb (97.07 and 87.89%) were higher than those of Cd (2.93 and 12.10%) in combined application for human and buffalo, respectively. This study highlights that the multi-metal contamination (Cd and Pb) is detrimental for wheat growth and human/animal health.

In this study, column-scale laboratory experiments were performed to evaluate the arsenic (As) removal efficiency of different agricultural biowastes-derived biosorbents (orange peel, banana peel, rice husk) and biochar, using As-containing solutions and As-contaminated groundwater. All the biosorbents and biochar efficiently removed (50-100%) As from groundwater (drinking well water). Arsenic removal potential of biosorbents varied with their type, As concentration, contact time, and As solution type. After 1 h, the As removal efficiency of all the biosorbents was 100%, 100% and 90% for 5, 10, and 50 µg/L As-contaminated groundwater samples, respectively; and it was 50%, 90%, and 90% for 10, 50, and 100 µg/L As solutions, respectively. After 2 h, all the biosorbents and biochar removed 100% As from aqueous solutions except for 100 µg/L As solution. This showed that the biosorbents and biochar could be used to reduce As contents below the WHO safe limit of As in drinking water (10 µg/L). Fourier transform infrared (FTIR) spectroscopy indicated possible role of various surface functional moieties on biosorbents/biochar surface to remove As from solution and groundwater. This pilot-scale column study highlights that the biosorbents and biochar can be effectively used in remediation of As-contaminated groundwater, although the soluble salts in groundwater increased after treatment with biochar.

Lead (Pb) is a ubiquitous pollutant which poses serious threats to plants, animals and humans once entered into the food chain via contaminated industrial effluents on their discharge into the surface of water bodies and/or geological materials. This study aimed to examine and compare the biosorption potential of natural sugarcane bagasse (NB), pyrolysed sugarcane bagasse (PB) and acid assisted pyrolysed sugarcane bagasse (APB) for the removal of Pb from contaminated water. To explore this objective, a series of batch experiments were conducted at various adsorbent mass (0.25, 0.5, 0.75, 1.0 g per 100 ml contaminated water), initial Pb concentration (7, 15, 30, 60 and 120 ppm), and contact time (7, 15, 30, 60 and 120 min). Results revealed that all the tested bio-sorbents have potential to adsorb and remove Pb ions from the contaminated water. In this regard, APB proved more effective since it removed 98% of Pb from aqueous solution at initial Pb concentration of 7 ppm and mass of 0.25 g per 100 ml of aqueous solution. The respective values in case of NB and PB were 90 and 95%. For a given adsorbent type, Pb adsorption decreased by increasing the mass from 0.25 to 1.0 g per 100 ml of aqueous solution. However, the greatest Pb removal occurred at adsorbent mass of 1.0 g per 100 ml of aqueous solution. Initial Pb concentration had a great impact on Pb adsorption and removal by adsorbent. The former increased and the latter decreased with the increase in initial Pb concentration from seven to 120 ppm. At seven ppm Pb concentration, maximum Pb removal took place irrespective to the adsorbent type. Out of the total Pb adsorption and removal, maximum contribution occurred within 15 min of contact time between the adsorbate and adsorbent, which slightly increased till 30 min, thereafter, it reached to equilibrium. Application of equilibrium isotherm models revealed that our results were better fitted with Freundlich adsorption isotherm model. Overall, and for the reasons detailed above, it is concluded that sugarcane bagasse has capabilities to adsorb and remove Pb ions from contaminated water. Its bio-sorption potential was considerably increased after pyrolysis and acid treatment., Competing Interests: The authors declare there are no competing interests.

Poultry manure (PM), a rich source for crop nutrients, is produced in ample quantities worldwide. It provides necessary nutrient to soil and has a potential to improve plant water holding availability under semiarid environment. The effect of composted poultry manure (CPM) and irrigation regimes on morpho-physiology of selective maize (Zea mays L.) hybrids (H 1 = drought tolerant, H 2 = drought sensitive) was investigated in this study. Two field experiments were conducted during 2010 and 2011 under randomized complete block design with split split-plot arrangements and three replications of each treatment. Irrigation regimes (I 1  = 300, I 2  = 450, I 3  = 600 mm) were kept in main plots; the two maize hybrids (H 1 and H 2 ) in sub-plots and nutrient levels (L 1 = recommended rate of NPK (control), L 2  = 8 t ha -1 CPM, L 3  = 10 t ha -1 CPM, and L 4  = 12 t ha -1 CPM) were arranged in sub sub-plots. The drought tolerant hybrid showed best growth under all treatments. Results revealed that maximum leaf area index (LAI) was recorded with the application of the recommended dose of NPK. Low irrigation regimes (I 1 and I 2 ) highly significantly (P < 0.01) reduced the photosynthesis and transpiration rate in both hybrids while application of 12 t ha -1 CPM was able to partially alleviate the effect of water stress on these parameters. Resultantly, the application of 12 t ha -1 CPM enhanced the plant growth and increased grain yield (21%; 4.17 vs 5.27) under limited water availability (I 2 L 4 ) as compared to the recommended dose of NPK (I 2 L 1 ). However, the nutrient application under control treatment had maximum grain yield. Therefore, shortage of water for maize production might be partially alleviated by the application of 12 t ha -1 CPM.

Silicon (Si) is the 2nd most abundant element in soil which is known to enhance stress tolerance in wide variety of crops. Arsenic (As), a toxic metalloid enters into the human food chain through contaminated water and food or feed. To alleviate the deleterious effect of As on human health, it is a need of time to find out an effective strategy to reduce the As accumulation in the food chain. The experiments were conducted during September-December 2014, and 2016 to optimize Si concentration for rice (Oryza sativa L.) exposed to As stress. Further experiment were carried out to evaluate the effect of optimum Si on rice seed germination, seedling growth, phosphorus and As uptake in rice plant. During laboratory experiment, rice seeds were exposed to 150 and 300µM As with and without 3mM Si supplementation. Results revealed that As application, decreased the germination up to 40-50% as compared to control treatment. Arsenic stress also significantly (P < 0.05) reduced the seedling length but Si supplementation enhanced the seedlings length. Maximum seedling length (4.94cm) was recorded for 3mM Si treatment while, minimum seedling length (0.60cm) was observed at day7 by the application of 300µM As. Silicon application resulted in 10% higher seedling length than the control treatment. In soil culture experiment, plants were exposed to same concentrations of As and Si under aerobic and anaerobic conditions. Irrigation water management, significantly (P˂0.05) affected the plant growth, Si and As concentrations in the plant. Arsenic uptake was relatively less under aerobic conditions. The maximum As concentration (9.34 and 27.70mgkg DW -1 in shoot and root, respectively) was found in plant treated with 300µM As in absence of Si under anaerobic condition. Similarly, anaerobic condition resulted in higher As uptake in the plants. The study demonstrated that aerobic cultivation is suitable to decrease the As uptake and in rice exogenous Si supply is beneficial to decrease As uptake under both anaerobic and aerobic conditions., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Agroforestry is a sustainable land use system with a promising potential to sequester atmospheric carbon into soil. This system of land use distinguishes itself from the other systems, such as sole crop cultivation and afforestation on croplands only through its potential to sequester higher amounts of carbon (in the above- and belowground tree biomass) than the aforementioned two systems. According to Kyoto protocol, agroforestry is recognized as an afforestation activity that, in addition to sequestering carbon dioxide (CO 2 ) to soil, conserves biodiversity, protects cropland, works as a windbreak, and provides food and feed to human and livestock, pollen for honey bees, wood for fuel, and timber for shelters construction. Agroforestry is more attractive as a land use practice for the farming community worldwide instead of cropland and forestland management systems. This practice is a win-win situation for the farming community and for the environmental sustainability. This review presents agroforestry potential to counter the increasing concentration of atmospheric CO 2 by sequestering it in above- and belowground biomass. The role of agroforestry in climate change mitigation worldwide might be recognized to its full potential by overcoming various financial, technical, and institutional barriers. Carbon sequestration in soil by various agricultural systems can be simulated by various models but literature lacks reports on validated models to quantify the agroforestry potential for carbon sequestration.

Arsenic (As) is a toxic metalloid. Serious concerns have been raised in literature owing to its potential toxicity towards living beings. The metalloid causes various water- and food-borne diseases. Among food crops, rice contains the highest concentrations of As. Consuming As-contaminated rice results in serious health issues. Arsenic concentration in rice is governed by various factors in the rhizosphere such as availability and concentration of various mineral nutrients (iron, phosphate, sulfur and silicon) in soil solution, soil oxidation/reduction status, inter-conversion between organic and inorganic As compounds. Agronomic and civil engineering methods can be adopted to decrease As accumulation in rice. Agronomic methods such as improving soil porosity/aeration by irrigation management or creating the conditions favorable for As-precipitate formation, and decreasing As uptake and translocation by adding a inorganic nutrients that compete with As are easy and cost effective techniques at field scale. This review focuses on the factors regulating and competing As in soil-plant system and As accumulation in rice grains. Therefore, it is suggested that judicious use of water, management of soil, antagonistic effects of various inorganic plant-nutrients to As should be considered in rice cultivated areas to mitigate the building up of As in human food chain and with minimum negative impact to the environment.

Knowledge of the dynamics of plant nitrogen (N) uptake at varying irrigation water levels is critical for strategizing increased N recovery efficiency (NRE), water use efficiency (WUE), and maize yield. The N dynamics were studied under various irrigation regimes to evaluate NRE, WUE, and maize yield. A pot experiment was conducted using three irrigation water regimes (50, 75, and 100% field capacity (FC)) and four N fertilizer rates (0, 1.6, 3.2, and 4.8 g pot -1 ) applied with two fertilizer application methods including foliar and soil applications. The highest plant growth and grain yields were achieved by application of 4.8 g N pot -1 with 100% FC. Contrarily, the maximum WUE (7.0 g L -1 ) was observed by the lowest irrigation water (50% FC) with the highest N fertilizer rates (4.8 g pot -1 ). Nitrogen concentration in the stem and grain was linearly increased by increasing N fertilizer rates with irrigation water. However, in the root, N concentration was decreased when the crop was supplied with 100% FC. In plant, maximum N uptake (6.5 mg g -1 ) was observed when 4.8 g N pot -1 was applied with 100% FC. Nitrogen recovery efficiency was increased by increasing N rate up to 3.2 g pot -1 with 100% FC. Therefore, for achieving maximum WUE and NRE, the highest water and N applications, respectively, are not necessary.