Future of ammonium nitrate after Beirut (Lebanon) explosion

Ammonium nitrate (NH4NO3) is a chemical compound that is mostly found as a colorless and/or white to gray crystalline solid, odorless beads, and easily soluble in water. The molecular weight, specific gravity, melting, and boiling point of NH4NO3 are 80.06, 1.725, 169.51 °C, and 210 °C, respectively (Rao, 2014). Higher temperature (>210 °C) easily decomposes NH4NO3 and producing toxic gasses, especially nitrogen oxides, and may also cause an explosion (Han et al., 2015). At room temperature, pure NH4NO3 neither flammable or combustible, but when heated, normally, it is decomposed into non-explosive gases such as oxygen. Nevertheless, it can also be decomposed into explosive material by detonation (Xia et al., 2019). Ammonium nitrate is strongly oxidant that easily detonates under certain circumstances, which include higher temperature (>210 °C), confinement, and impurities (Health Safety Executive, 2004).The authors would like to appreciate the valuable comments from the editors and anonymous reviewers to improve the quality of this study. The authors confirm that no funding was received for his work

Seven years of pig slurry fertilization: impacts on soil chemical properties and the element content of winter barley plants

Intensive pig farming produces large amounts of slurry, which is applied to agricultural soils as fertilizer. A 7-year field study was performed to check the effect of pig slurry on soil properties and on the accumulation of some essential nutrients and heavy metals in a calcareous silty-loam soil (0-0.3 m) and in barley (Hordeum vulgare L.) plants in two cropping seasons with contrasting amounts of rainfall. Five fertilization treatments, control (no N applied), mineral fertilizer (90 kg N ha(-1)), and different N doses of pig slurry (146, 281, 534 kg N ha(-1)), were applied at sowing of a barley crop. Organic carbon, available P and K, and total P in soil increased with slurry dose. No differences were found in Co, Cr, Fe, Mn, Ni, and Pb soil concentrations. Slurries increased Cu, Mn, and Zn extractions and plant concentrations of P in straw and Zn in grain. However, the lowest slurry rate was able to maintain the highest grain yields while improving fertility. The results of this research study support the sustainability of pig slurry fertilization at appropriate rates in relation to soil chemical quality.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported by the Spanish Ministry of Economy and Competitiveness and the Spanish National Institute for Agricultural Research and Experimentation (MINECO-INIA) through the project RTA2017-88-C3-3. The author A. Shakoor received a grant from the University of Lleida for his PhD studies (from 2019 to 2022 period)

The Carbon Emission Trading Policy of China: Does It Really Boost the Environmental Upgrading?

China’s rapid industrialization has led to massive resource consumption, and the country has recently been highlighted as the World’s top carbon emitter. To pursue a sustainable economy via environmental upgrading, reductions in carbon emission levels are of great concern. The carbon emission reduction policy (CETP) is an environmental regulation aimed at cutting emissions and achieving environmental protection. Based on panel data of pilot and non-pilot regions, this study investigated the policy impact of the CETP on carbon emission reduction through difference-in differences (DID). The findings, based on pooled OLS (ordinary least squares) and LSDV (least square dummy variable) regressions, revealed that the carbon emissions of the pilot regions (Beijing, Tianjin, Shanghai, Guangdong, Chongqing, and Hubei) had reduced by 12 percent more than the non-pilot regions. Thus, this implies that the CETP causes environmental upgrading. The results were further verified using a number of robustness checks, including parallel trends, placebo test, Granger causality test, and DID regression with a longer sample period. Based on the study findings, it was concluded that to achieve higher upgrade levels related to the environment, the CETP needs to be encouraged and improved for nationwide implementation. Furthermore, sustainable economic development in China also needs strict environmental regulations and policy measures

Uptake and Accumulation of Nano/Microplastics in Plants: A Critical Review

The ubiquitous presence of microplastics (MPs) and nanoplastics (NPs) in the environment is an undeniable and serious concern due to their higher persistence and extensive use in agricultural production. This review highlights the sources and fate of MPs and NPs in soil and their uptake, translocation, and physiological effects in the plant system. We provide the current snapshot of the latest reported studies with the majority of literature spanning the last five years. We draw attention to the potential risk of MPs and NPs in modern agriculture and their effects on plant growth and development. We also highlight their uptake and transport pathways in roots and leaves via different exposure methods in plants. Conclusively, agricultural practices, climate changes (wet weather and heavy rainfall), and soil organisms play a major role in transporting MPs and NPs in soil. NPs are more prone to enter plant cell walls as compared to MPs. Furthermore, transpiration pull is the dominant factor in the plant uptake and translocation of plastic particles. MPs have negligible negative effects on plant physiological and biochemical indicators. Overall, there is a dire need to establish long-term studies for a better understanding of their fate and associated risks mechanisms in realistic environment scenarios for safe agricultural functions

Screening of rice cultivars for Cr-stress response by using the parameters of seed germination, morpho-physiological and antioxidant analysis

Rice is the most important crop for the majority of population across the world with sensitive behavior toward heavy metals such as chromium (Cr) in polluted regions. Although, there is no information on the Cr resistance phenotyping in rice. Herein, two different groups of rice cultivars (normal, and hybrid) were used, each group with 14 different rice cultivars. Firstly, seed germination analysis was conducted by evaluating various seed germination indices to identify the rice cultivars with greatest seed germination vigor. Furthermore, exposure of chromium (Cr) toxicity to 28 different rice varieties (NV1-NV14, HV1-HV14) caused noticeable plant biomass reduction. Subsequently, NV2, NV6, NV10, NV12, NV13 (normal type), HV1, HV4, HV8, and HV9 (hybrid types) were pragmatic as moderately sensitive varieties, while NV3, NV4, NV9, and NV14 (normal type), HV3, HV6, HV7, and HV13 were observed as moderately tolerant. Although, NV7, and HV10 were ranked most sensitive cultivars, and NV11, and HV14 were considered as most tolerant varieties as compared to the other rice (both groups) genotypes. Afterward, Cr induced reduction in chlorophyll pigments were significantly lesser in HV14 relative to NV11, NV7, and especially HV10, and as a result HV14 modulated the total soluble sugar level as well as reduced ROS accumulation, and MDA contents production by stimulating the antioxidant defense mechanism conspicuously which further reduced the electrolyte leakage as well. Our outcomes provide support to explore the Cr tolerance mechanism in cereal crops as well as knowledge about rice breeding with increased tolerance against Cr stress.This research was supported by National Natural Science Foundation of China (No. 32072127), Zhejiang Provincial Natural Science Foundation (No. LY21C130006), Dabeinong Funds for Discipline Development and Talent Training in Zhejiang University, Collaborative Innovation Center for Modern Crop Production co-sponsored by Province and Ministry (CIC-MCP) and Zhenjiang International-joint fund (No. GJ2020010). The authors would like to extend their sincere appreciation to the Researchers Supporting Project Number (RSP-2021/168), King Saud University, Riyadh, Saudi Arabia

Development and characterization of efficient k-solubilizing rhizobacteria and mesorhizobial inoculants for chickpea

The use of mineral fertilizers has long been associated with the improved growth of crop plants as well as increased yield potential per unit area. However, the incessant practice of imbalanced fertilizers application has increased the economic and environmental costs for the agricultural sector. The deficiency of potassium (K) has been identified as a primary crop production challenge in certain semi-arid regions where soil-K reserves are increasingly being depleted. This study aimed to isolate and characterize K-solubilizing bacterial strains from the rhizosphere and root nodules of chickpea. Initially, 50 rhizobacterial strains and 50 rhizobial strains were isolated using Aleksandrov’s medium. Each of these collections was narrowed down to 25 strains, following a rigorous qualitative screening based on different physiological, morphological and biochemical tests. From these, five strains each of rhizosphere and nodule origins were selected based on qualitative as well quantitative determination of various growth promoting traits. In addition to efficient potassium and phosphate solubilization, the selected strains displayed better growth conditions, as evident by glucose substrate use at 25◦C and pH 7. In this study, we found that strains SKB3 (rhizosphere) and JKR7 (rhizobia) were the most efficient K-solubilizers. Additionally, they possessed diverse plant growth promoting traits such as root colonization, the synthesis of siderophores, exopolysaccharides, chitinase activity, indole-acetic acid production and 1-aminocyclopropane-1-carboxylic acid deaminase activity. Overall, our results suggest that the application of bacterial K-solubilizers could be employed as a useful K-supplement in K-limited agroecosystems. Moreover, the use of these K-solubilizers may help lead in alleviating the negative environmental impacts associated with chemical fertilizer.I am very grateful to all of those with whom I have had the pleasure to work during this project, especially the Department of Soil and Environmental Sciences, College of Agriculture, University of Sargodha, Sargodha, Pakistan, the Soil & Water Sciences Department (SWD), Institute of Food and Agricultural Sciences (IFAS), University of Florida, USA, and the Higher Education Commission (HEC), Islamabad, Pakistan. Each of the members of the SWD, IFAS, University of Florida, USA, specifically L.Q. Ma, Letuzia Maria De Oliveira and Evandro Da Silva have provided me with extensive personal and professional guidance and have taught me a great deal about both scientific research and life in general during my six months stay there under International Research Support Initiative Program (IRSIP), HEC, Pakistan. The authors would also like to extend their sincere appreciation to the acknowledgment of the research supporting project (RSP-2021/95, King Saud University, Riyadh, Saudi Arabia)

Effect of animal manure, crop type, climate zone, and soil attributes on greenhouse gas emissions from agricultural soils A global meta-analysis

Agricultural lands, because of their large area and exhaustive management practices, have a substantial impact on the earth's carbon and nitrogen cycles, and agricultural activities consequence in discharges of greenhouse gases (GHGs). Globally, greenhouse gases (GHGs) emissions especially carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from the agricultural sector are increasing due to anthropogenic activities. Although, the application of animal manure to the agricultural soil as an organic fertilizer not only improves soil health and agricultural production but also has a significant impact on GHGs emissions. But the extent of GHGs emissions in response to manure application under diverse environmental conditions is still uncertain. Here, a meta-analysis study was conducted using field data (48 peer-reviewed publications) published from 1989 to 2019. Meta-analysis results showed that poultry manure considerably increased CO2, CH4, and N2O emissions than pig and cattle manure. Furthermore, application of poultry manure also increased (¯(〖lnRR〗^ ) =0.141, 95% CI =0.526-0.356) GWP (global warming potential) of total soil GHGs emissions. While, the significant effects on CO2, CH4, and N2O emissions also occurred at manure rate > 320 kg N ha-1 and > 60% water filled pore space. The maximum concentrations of CO2, CH4, and N2O emissions were observed in neutral soils (¯(〖lnRR〗^ ) =3.375, 95% CI =3.323-3.428), alkaline soils (¯(〖lnRR〗^ ) =1.468, 95% CI =1.403-1.532), and acidic soils (¯(〖lnRR〗^ ) =2.355, 95% CI =2.390-2.400), respectively. Soil texture, climate zone and crop type were also found significant factors to increase GHGs emissions. Thus, this meta-analysis revealed a knowledge gap concerning the consequences of animal manure application and rate, climate zone, and physicochemical properties of soil on GHGs emissions from agricultural soils.Awais Shakoor would like to express his gratitude for the grant provided by the University of Lleida, Spain. The authors would like to appreciate the valuable comments from the editors and anonymous reviewers to improve the quality of this study

Unraveling the Influence of Land-Use Change on δ 13C, δ 15N, and Soil Nutritional Status in Coniferous, Broadleaved, and Mixed Forests in Southern China: A Field Investigation

Natural isotopic abundance in soil and foliar can provide integrated information related to the long-term alterations of carbon (C) and nitrogen (N) cycles in forest ecosystems. We evaluated total carbon (TC), total nitrogen (TN), and isotopic natural abundance of C (δ 13C) and N (δ 15N) in soil and foliar of coniferous plantation (CPF), natural broadleaved forest (NBF), and mixed forest stands at three different soil depths (i.e., 0–10, 10–20, and 20–40 cm). This study also explored how soil available nutrients are affected by different forest types. Lutou forest research station, located in Hunan Province, central China, was used as the study area. Results demonstrated that the topsoil layer had higher TC and TN content in the mixed forest stand, resulting in a better quality of organic materials in the topsoil layer in the mixed forest than NBF and CPF. In general, soil TC, TN, and δ 15N varied significantly in different soil depths and forest types. However, the forest type did not exhibit any significant effect on δ 13C. Overall, soil δ 13C was significantly enriched in CPF, and δ 15N values were enriched in mixed forest. Foliar C content varied significantly among forest types, whereas foliar N content was not significantly different. No big differences were observed for foliar δ 15N and δ 13C across forest types. However, foliar δ 13C and δ 15N were positively related to soil δ 13C and δ 15N, respectively. Foliar N, soil and foliar C:N ratio, soil moisture content (SMC), and forest type were observed as the major influential factors affecting isotopic natural abundance, whereas soil pH was not significantly correlated. In addition, forest type change and soil depth increment had a significant effect on soil nutrient availability. In general, soil nutrient availability was higher in mixed forest. Our findings implied that forest type and soil depth alter TC, TN, and soil δ 15N, whereas δ 13C was only driven by soil depth. Moreover, plantations led to a decline in soil available nutrient content compared with NBF and mixed forest stand

Investigating the Impacts of the COVID-19 Lockdown on Trace Gases Using Ground-Based MAX-DOAS Observations in Nanjing, China

The spread of the COVID-19 pandemic and consequent lockdowns all over the world have had various impacts on atmospheric quality. This study aimed to investigate the impact of the lockdown on the air quality of Nanjing, China. The off-axis measurements from state-of-the-art remote-sensing Multi-Axis Differential Optical Absorption Spectroscope (MAX-DOAS) were used to observe the trace gases, i.e., Formaldehyde (HCHO), Nitrogen Dioxide (NO2), and Sulfur Dioxide (SO2), along with the in-situ time series of NO2, SO2 and Ozone (O3). The total dataset covers the span of five months, from 1 December 2019, to 10 May 2020, which comprises of four phases, i.e., the pre lockdown phase (1 December 2019, to 23 January 2020), Phase-1 lockdown (24 January 2020, to 26 February 2020), Phase-2 lockdown (27 February 2020, to 31 March 2020), and post lockdown (1 April 2020, to 10 May 2020). The observed results clearly showed that the concentrations of selected pollutants were lower along with improved air quality during the lockdown periods (Phase-1 and Phase-2) with only the exception of O3, which showed an increasing trend during lockdown. The study concluded that limited anthropogenic activities during the spring festival and lockdown phases improved air quality with a significant reduction of selected trace gases, i.e., NO2 59%, HCHO 38%, and SO2 33%. We also compared our results with 2019 data for available gases. Our results imply that the air pollutants concentration reduction in 2019 during Phase-2 was insignificant, which was due to the business as usual conditions after the Spring Festival (Phase-1) in 2019. In contrast, a significant contamination reduction was observed during Phase-2 in 2020 with the enforcement of a Level-II response in lockdown conditions i.e., the easing of the lockdown situation in some sectors during a specific interval of time. The observed ratio of HCHO to NO2 showed that tropospheric ozone production involved Volatile Organic Compounds (VOC) limited scenarios.This work was supported by the National Natural Science Foundation of China (NSFC, 41701551, 41605117, 41771291). Y.W. was supported by the National Science Foundation

The interactive impact of straw mulch and biochar application positively enhanced the growth indexes of maize (Zea mays L.) crop

A two-year experiment was carried out at Shenyang Agricultural University’s research field area in China to evaluate the impact of the combined application of straw mulch (0 and 8 t ha−1) and biochar (0, 4, 12, and 36 t ha−1) on the morphological traits and grain development of rainfed maize during 2018 and 2019. The results showed that straw mulch and different biochar application rates significantly impacted the maize growth index. Compared to non-biochar-treated soils, the introduction of straw mulch improved plant height, stem diameter, leaf area index (LAI), leaves, stem, root, and crop growth rate (CGR), and dry weight of rainfed maize crop. The highest plant height, stem diameter, LAI, leaves, stem, root growth rate, CGR, and dry weight of rainfed maize crop were reported when soil was treated with a higher rate of biochar (36 t ha−1). Biochar increased grain filling rate while decreasing grain filling duration in rainfed maize crops. Our results indicate that straw mulch and biochar-based soil management strategies can improve the rainfed maize growth with the environmental benefits of global warming mitigation. However, due to the wide range of biochar properties, the interactions between straw mulch and biochar should be given special consideration in the maize cropping system