Publications

Export 44 results:
Sort by: Author Title Type [ Year  (Desc)]
2022
Addition of walnut shells biochar to alkaline arable soil caused contradictory effects on CO2 and N2O emissions, nutrients availability, and enzymes activity, Sial, Tanveer Ali, Shaheen Sabry M., Lan Zhilong, Korai Punhoon Khan, Ghani Muhammad Imran, Khan Muhammad Numan, Syed Ain-ul-Abad, Hussain Asghar Ali Main Noor, Rajpar Inayatullah, Memon Mehrunisa, et al. , Chemosphere, 2022, Volume 293, p.133476, (2022) AbstractWebsite

Mitigation of greenhouse gas (GHGs) emissions and improving soil health using biochar (BC) shall help achieving the UN-Sustainable Development Goals. The impacts of walnut shells biochar (WSB) pyrolyzed at different temperatures on CO2 and N2O emission and soil health have not been yet sufficiently explored. We investigated the effects of addition of WSB pyrolyzed at either 300 °C (WSB-300), 450 °C (WSB-450), or at 600 °C (WSB-600) to alkaline soil on CO2 and N2O emissions, nutrients availability, and soil enzymes activities in a 120-day incubation experiment. Cumulative N2O emissions were reduced significantly as compared to the control, by 64.9%, 50.6%, and 36.4% after WSB-600, WSB-450 and WSB-300, respectively. However, the cumulative CO2 emissions increased, over the control, as follows: WSB-600 (50.7%), WSB-450 (68.6%), and WSB-300 (73.4%). Biochar addition, particularly WSB-600 significantly increased soil pH (from 8.1 to 8.34), soil organic C (SOC; from 8.6 to 22.3 g kg−1), available P (from 21.0 to 60.5 mg kg−1), and K (181.0–480.5 mg kg−1), and activities of urease, alkaline phosphatase, and invertase. However, an opposite pattern was observed with NH4+, NO3−, total N and β-glucosidase activity after WSB application. The WBS produced from high temperature pyrolysis can be used for N2O emissions mitigation and improvement of soil pH, SOC, available P and K, and activities of urease, alkaline, phosphatase. However, WBS produced from low temperature pyrolysis can be used to promote N availability and β-glucosidase; however, these findings should be verified under different field and climatic conditions.

Earthworms as candidates for remediation of potentially toxic elements contaminated soils and mitigating the environmental and human health risks: A review, Xiao, Ran, Ali Amjad, Xu Yaqiong, Abdelrahman Hamada, Li Ronghua, Lin Yanbing, Bolan Nanthi, Shaheen Sabry M., Rinklebe Jörg, and Zhang Zengqiang , Environment International, 2022, Volume 158, p.106924, (2022) AbstractWebsite

Global concerns towards potentially toxic elements (PTEs) are steadily increasing due to the significant threats that PTEs pose to human health and environmental quality. This calls for immediate, effective and efficient remediation solutions. Earthworms, the 'ecosystem engineers', can modify and improve soil health and enhance plant productivity. Recently, considerable attention has been paid to the potential of earthworms, alone or combined with other soil organisms and/or soil amendments, to remediate PTEs contaminated soils. However, the use of earthworms in the remediation of PTEs contaminated soil (i.e., vermiremediation) has not been thoroughly reviewed to date. Therefore, this review discusses and provides comprehensive insights into the suitability of earthworms as potential candidates for bioremediation of PTEs contaminated soils and mitigating environmental and human health risks. Specifically, we reviewed and discussed: i) the occurrence and abundance of earthworms in PTEs contaminated soils; ii) the influence of PTEs on earthworm communities in contaminated soils; iii) factors affecting earthworm PTEs accumulation and elimination, and iv) the dynamics and fate of PTEs in earthworm amended soils. The technical feasibility, knowledge gaps, and practical challenges have been worked out and critically discussed. Therefore, this review could provide a reference and guidance for bio-restoration of PTEs contaminated soils and shall also help developing innovative and applicable solutions for controlling PTEs bioavailability for the remediation of contaminated soils and the mitigation of the environment and human risks.

Improving the humification and phosphorus flow during swine manure composting: A trial for enhancing the beneficial applications of hazardous biowastes, Zhang, Tao, Wu Xiaosha, Shaheen Sabry M., Abdelrahman Hamada, Ali Esmat F., Bolan Nanthi S., Ok Yong Sik, Li Guoxue, Tsang Daniel C. W., and Rinklebe Jörg , Journal of Hazardous Materials, 2022, Volume 425, p.127906, (2022) AbstractWebsite

Improving the recovery of organic matter and phosphorus (P) from hazardous biowastes such as swine manure using acidic substrates (ASs) in conjunction with aerobic composting is of great interest. This work aimed to investigate the effects of ASs on the humification and/or P migration as well as on microbial succession during the swine manure composting, employing multivariate and multiscale approaches. Adding ASs, derived from wood vinegar and humic acid, increased the degree of humification and thermal stability of the compost. The 31P nuclear magnetic resonance spectroscopy and X-ray absorption near-edge structure analyses demonstrated compost P was in the form of struvite crystals, Ca/Al-P phases, and Poly-P (all inorganic P species) as well as inositol hexakisphosphate and Mono-P (organophosphorus species). However, the efficiency of P recovery could be improved by generating more struvite by adding the ASs. The flows among nutrient pools resulted from the diversity in the dominant microbial communities in different composting phases after introducing the ASs and appearance of Bacillus spp. in all phases. These results demonstrate the potential value of ASs for regulating and/or improving nutrients flow during the composting of hazardous biowastes for producing higher quality compost, which may maximize their beneficial benefits and applications.

Manganese oxide-modified biochar: production, characterization and applications for the removal of pollutants from aqueous environments - a review, Shaheen, Sabry M., Natasha, Mosa Ahmed, El-Naggar Ali, Faysal Hossain Md, Abdelrahman Hamada, Niazi Nabeel Khan, Shahid Muhammad, Zhang Tao, Tsang Yiu Fai, et al. , Bioresource Technology, 2022, Volume 346, p.126581, (2022) AbstractWebsite

The development of manganese (Mn) oxides (MnOx) modified biochar (MnOBC) for the removal of pollutants from water has received significant attention. However, a comprehensive review focusing on the use of MnOBC for the removal of organic and inorganic pollutants from water is missing. Therefore, the preparation and characterization of MnOBC, and its capacity for the removal of inorganic (e.g., toxic elements) and organic (e.g., antibiotics and dyes) from water have been discussed in relation to feedstock properties, pyrolysis temperature, modification ratio, and environmental conditions here. The removal mechanisms of pollutants by MnOBC and the fate of the sorbed pollutants onto MnOBC have been reviewed. The impregnation of biochar with MnOx improved its surface morphology, functional group modification, and elemental composition, and thus increased its sorption capacity. This review establishes a comprehensive understanding of synthesizing and using MnOBC as an effective biosorbent for remediation of contaminated aqueous environments.

Sustainable applications of rice feedstock in agro-environmental and construction sectors: A global perspective, Shaheen, Sabry M., Antoniadis Vasileios, Shahid Muhammad, Yang Yi, Abdelrahman Hamada, Zhang Tao, Hassan Noha E. E., Bibi Irshad, Niazi Nabeel Khan, Younis Sherif A., et al. , Renewable and Sustainable Energy Reviews, 2022, Volume 153, p.111791, (2022) AbstractWebsite

Rice is second only to maize among the world's most important cereal crops, with a global harvested area of approximately 158 million hectares and an annual production of more than 700 million tonnes as paddy rice. At this scale, rice production generates vast amounts of waste in the form of straw, husk, and bran. Because of high cellulose, lignin, and silica contents, rice biowaste (RB) can be used to produce rice biochar (RBC) and rice compost (RC). Furthermore, RB can be used as sorbents, soil conditioners, bricks/concrete blocks, flat steel products, and biofuels, all of which make significant contributions to meeting United Nations Sustainable Development Goals (UNSDGs). Although previous reviews have explored individual applications of rice feedstocks, inadequate attention has been paid to multifunctional values and potential multi-utilities. Here, we offer a comprehensive review of RBC and RC with respect to: (1) preparation and characterization; (2) applications as soil conditioners and organic fertilizers and their effects on soil-carbon sequestration; (3) remediation of toxic element–contaminated soils and water; (4) removal of colors, dyes, endocrine-disrupting chemicals, personal-care products, and residual pesticides from water; and (5) applications in the construction industry. Specifically, we describe the opportunities for the sustainable use of RBC and RC in the management of contaminated soils and water as well as the construction industry. Overall, this review is expected to lengthen the list of possible multifunctional applications of RBC and RC.

Removal of potentially toxic elements from contaminated soil and water using bone char compared to plant- and bone-derived biochars: A review, Azeem, Muhammad, Shaheen Sabry M., Ali Amjad, Jeyasundar Parimala G. S. A., Latif Abdul, Abdelrahman Hamada, Li Ronghua, Almazroui Mansour, Niazi Nabeel Khan, Sarmah Ajit K., et al. , Journal of Hazardous Materials, Volume 427, p.128131, (2022) AbstractWebsite

Conversion of hazardous waste materials to value-added products is of great interest from both agro-environmental and economic points of view. Bone char (BC) has been used for the removal of potentially toxic elements (PTEs) from contaminated water, however, its potential BC for the immobilization of PTEs in contaminated water and soil compared to bone (BBC)- and plant (PBC)-derived biochars has not been reviewed yet. This review presents an elaboration for the potentials of BC for the remediation of PTEs-contaminated water and soil in comparison with PBC and BBC. This work critically reviews the preparation and characterization of BC, BBC, and PBC and their PTEs removal efficiency from water and soils. The mechanisms of PTE removal by BC, BBC, and PBC are also discussed in relation to their physicochemical characteristics. The review demonstrates the key opportunities for using bone waste as feedstock for producing BC and BBC as promising low-cost and effective materials for the remediation of PTEs-contaminated water and soils and also elucidates the possible combinations of BC and BBC aiming to effectively immobilize PTEs in water and soils.

2021
Bone-derived biochar improved soil quality and reduced Cd and Zn phytoavailability in a multi-metal contaminated mining soil, Azeem, Muhammad, Ali Amjad, Soundari Parimala G., Yiman Li, Abdelrahman Hamada, Latif Abdul, Ronghua Li, Basta Nicholas, Li Gang, Shaheen Sabry M., et al. , Environmental Pollution, 2021, p.116800, (2021) AbstractWebsite

Reusing by-products such as cow bones in agriculture can be achieved thorough pyrolysis. The potential of bone-derived biochar as a promising material for metals immobilization in contaminated mining soils has not yet been sufficiently explored. Therefore, cow bones were used as biochar feedstock were pyrolyzed at 500 °C (CBL) and 800 °C (CBH) and. The two biochars were applied to a mine contaminated soil at 0 (control), 2.5, 5 and 10%, w/w, dosages; then, the soils were incubated and cultivated by maize in the greenhouse. Cadmium (Cd) and zinc (Zn) bioavailability and their sequentially extracted fractions (acid soluble, reducible, oxidizable, and residual fraction), soil microbial function, and plant health attributes were analyzed after maize harvesting. Bone-derived biochar enhanced the content of dissolved organic carbon (up to 74%), total nitrogen (up to 26%), and total phosphorus (up to 27%) in the soil and improved the plant growth up to 55%, as compared to the control. The addition of CBL altered the acid soluble fraction of both metals to the residual fraction and, thus, reduced the content of Zn (55 and 40%) and Cd (57 and 67%) in the maize roots and shoots, respectively as compared to the control. The CBL enhanced the β-glucosidase (51%) and alkaline phosphatase activities (71%) at the lower doses (2.5–5%) as compared to control, while the activities of these enzymes decreased with the higher application doses. Also, CBL improved the antioxidants activity and maize growth at the 2.5–5% application rate. However, the activity of the dehydrogenase significantly decreased (77%), particularly with CBH. We conclude that CBL, applied at 2.5–5% dose, can be utilized as a potential low cost and environmental friendly amendment for stabilization of toxic metals in contaminated mining soils and producing food/feed/biofuel crops with lower metal content.

Green remediation of toxic metals contaminated mining soil using bacterial consortium and Brassica juncea, Soundari Arockiam Jeyasundar, Parimala Gnana, Ali Amjad, Azeem Muhammad, Li Yiman, Guo Di, Sikdar Ashim, Abdelrahman Hamada, Kwon Eilhann, Antoniadis Vasileios, Mani Vellingiri Manon, et al. , Environmental Pollution, 2021, p.116789, (2021) AbstractWebsite

Microorganism-assisted phytoremediation is being developed as an efficient green approach for management of toxic metals contaminated soils and mitigating the potential human health risk. The capability of plant growth promoting Actinobacteria (Streptomyces pactum Act12 - ACT) and Firmicutes (Bacillus subtilis and Bacillus licheniformis - BC) in mono- and co-applications (consortium) to improve soil properties and enhance phytoextraction of Cd, Cu, Pb, and Zn by Brassica juncea (L.) Czern. was studied here for the first time in both incubation and pot experiments. The predominant microbial taxa were Proteobacteria, Actinobacteria and Bacteroidetes, which are important lineages for maintaining soil ecological activities. The consortium improved the levels of alkaline phosphatase, β-D glucosidase, dehydrogenase, sucrase and urease (up to 33%) as compared to the control. The bacterial inoculum also triggered increases in plant fresh weight, pigments and antioxidants. The consortium application enhanced significantly the metals bioavailability (DTPA extractable) and mobilization (acid soluble fraction), relative to those in the unamended soil; therefore, significantly improved the metals uptake by roots and shoots.The phytoextraction indices indicated that B. juncea is an efficient accumulator of Cd and Zn. Overall, co-application of ACT and BC can be an effective solution for enhancing phytoremediation potential and thus reducing the potential human health risk from smelter-contaminated soil. Field studies may further credit the understanding of consortium interactions with soil and different plant systems in remediating multi-metal contaminated environments.

Streptomyces pactum addition to contaminated soils improved soil quality and plant growth and enhanced metals phytoextraction: A trial for green remediation and sustainable management of mining soils, Ali, Amjad, Guo Di, Li Yiman, Shaheen Sabry M., Wahid Fazli, Antoniadis Vasileios, Abdelrahman Hamada, Al-Solaimani Samir G., Li Ronghua, Tsang Daniel C. W., et al. , Chemosphere, 2021, Volume 273, p.129692, (2021) AbstractWebsite

Streptomyces pactum (Act12), an agent of a gentle in situ remediation approach, has been recently used in few works in phytoextraction trials; however, the impact of Act12 on soil quality and metal phytoavailability has not been assessed in multi-metal contaminated soils. Consequently, here we assessed the potential impact of Act12 on the wheat (Triticum aestivum L.) growth, antioxidants activity, and the metal bioavailability in three industrial and mining soils collected from China and contained up to 118, 141, 339, and 6625 mg Cd, Cu, Pb, and Zn kg–1 soil, respectively. The Act12 was applied at 0 (control), 0.75 (Act-0.75), 1.50 (Act-1.5), and 2.25 (Act-2.25) g kg–1 (dry weight base) to the three soils; thereafter, the soils were cultivated with wheat (bio-indicator plant) in a pot experiment. The addition of Act12 (at Act-1.5 and Act-2.25) promoted wheat growth in the three soils and significantly increased the content of Cd, Cu, and Zn in the roots and shoots and Pb only in the roots (up to 121%). The Act12-induced increase in metals uptake by wheat might be attributed to the associated decrease in soil pH and/or the increase of metal chelation and production of indole acetic acid and siderophores. The Act12 significantly decreased the antioxidant activities and lipid peroxidation in wheat, which indicates that Act12 may mitigate metals stress in contaminated soils. Enhancing metals phytoextraction using Act12 is a promising ecofriendly approach for phytoremediation of metal-contaminated mining soils that can be safely utilized with non-edible plants and/or bioenergy crops.

Wheat and maize-derived water-washed and unwashed biochar improved the nutrients phytoavailability and the grain and straw yield of rice and wheat: A field trial for sustainable management of paddy soils, Korai, Punhoon Khan, Sial Tanveer Ali, Pan Genxing, Abdelrahman Hamada, Sikdar Ashim, Kumbhar Farhana, Channa Siraj Ahmed, Ali Esmat F., Zhang Jianguo, Rinklebe Jörg, et al. , Journal of Environmental Management, 2021, Volume 297, p.113250, (2021) AbstractWebsite

A field experiment was carried out to evaluate the effects of different biochars on grain yield and phytoavailability and uptake of macro- and micro-nutrients by rice and wheat grown in a paddy soil in a rotation. Soil was treated with i) maize raw (un-washed) biochar (MRB), ii) maize water-washed biochar (MWB), iii) wheat raw biochar (WRB) or iv) wheat water-washed biochar (WWB) and untreated soil was used as control (CF). Inorganic fertilizers were applied to all soils while biochar treated soils received 20 ton ha−1 of designated biochar before rice cultivation in rice-wheat rotation. The WRB significantly (P < 0.05) increased rice grain yield and straw by up to 49%, compared to the CF. Biochar addition, particularly WRB, significantly increased the availability of N, P, K and their content in the grain (26–37%) and straw (22–37%) of rice and wheat. Also, the availability and grain content of Fe, Mn, Zn, and Cu increased significantly after biochar addition, particularly after the WRB, due to WRB water dissolved C acting as a carrier for micronutrients in soil and plant. However, the water-washing process altered biochar properties, particularly the water extractable C, which decreased its efficiency. Both wheat- and maize-derived biochars, particularly the WRB, are recommended to improve nutrients availability and to improve grain yield in the rice-wheat rotation agro-ecosystem. These results shed light on the importance of crop straw transformation into an important source for soil C and nutrients necessary for sustainable management of wheat-rice agro-ecosystem. However, with the current and future alternative energy demands, the decision on using crop biomass for soil conservation or for bioenergy becomes a challenge reliant on regulatory and policy frameworks.

Effects of sheep bone biochar on soil quality, maize growth, and fractionation and phytoavailability of Cd and Zn in a mining-contaminated soil, Azeem, Muhammad, Ali Amjad, Arockiam Jeyasundar Parimala G. S., Bashir Saqib, Hussain Qaiser, Wahid Fazli, Ali Esmat F., Abdelrahman Hamada, Li Ronghua, Antoniadis Vasileios, et al. , Chemosphere, Volume 282, p.131016, (2021) AbstractWebsite

Biochar prepared from various feedstock materials has been utilized in recent years as a potential stabilizing agent for heavy metals in smelter-contaminated soils. However, the effectiveness of animal bone-derived biochar and its potential for the stabilization of contaminants remains unclear. In the present study, sheep bone-derived biochar (SB) was prepared at low (500 °C; SBL) and high temperatures (800 °C; SBH) and amended a smelter-contaminated soil at 2, 5, and 10% (w/w). The effects of SB on soil properties, bioavailable Zn and Cd and their geochemical fractions, bacterial community composition and activity, and the response of plant attributes (pigments and antioxidant activity) were assessed. Results showed that the SBH added at 10% (SBH10) increased soil organic carbon, total nitrogen, and phosphorus, and also increased the oxidizable and residual Zn and Cd fractions at the expense of the bioavailable fractions. The SBH10 lowered the Zn and Cd contents in maize roots (by 57 and 60%) and shoot (by 42 and 61%), respectively, compared to unamended control. Additionally, SBH10 enhanced urease (98%) and phosphates (107%) activities, but reduced dehydrogenase (58%) and β-glucosidase (30%) activities. Regarding the effect of the pyrolysis temperature, SBH enhanced the activity of Acidobacteria, Bacteroidetes, Firmicutes, Nitrospirae, Verrucomicrobia, Chlorobi, and Microgenomates, but reduced Actinobacteria and Parcubacteria in comparison to SBL. However, only the SBL10 reduced the Proteobacteria community (by 9%). In conclusion, SB immobilized Zn and Cd in smelter-affected soils, enhanced the bacterial abundance and microbial function (urease, phosphates), and improved plant growth. However, validation of the results, obtained from the pot experiment, under field conditions is suggested.

Fe/Mn- and P-modified drinking water treatment residuals reduced Cu and Pb phytoavailability and uptake in a mining soil, Wang, Quan, Shaheen Sabry M., Jiang Yahui, Li Ronghua, Slaný Michal, Abdelrahman Hamada, Kwon Eilhann, Bolan Nanthi, Rinklebe Jörg, and Zhang Zengqiang , Journal of Hazardous Materials, Volume 403, p.123628, (2021) AbstractWebsite

Management of industrial hazardous waste is of great concern. Recently, aluminum rich drinking water treatment residuals (Al-WTR) received considerable attention as a low-cost immobilizing agent for toxic elements in soils. However, the suitability and effectiveness of modified Al-WTR as stabilizing agent for toxic metals such as Cu and Pb in mining soil is not assessed yet. We examined the impact of different doses (0, 0.5, 1.5, and 2.5%) of raw and Fe/Mn- and P- modified Al-WTR on the bioavailability and uptake of Cu and Pb by ryegrass in Cu and Pb contaminated mining soil. The addition of Fe/Mn-and P- modified Al-WTR to the soil reduced significantly the concentrations of Pb (up to 60% by Fe/Mn-Al-WTR and 32% by P-Al-WTR) and Cu (up to 45% by Fe/Mn-Al-WTR and 18% by P-Al-WTR) in the shoots and roots of ryegrass as compared to raw Al-WTRs and untreated soil. Our results demonstrate that modification of the raw Al-WTR increased its pH, CEC, specific surface area, active functional groups (Fe-O and Mn-O), and thus increased its immobilization efficiency. Our results highlight the potential of the modified Al-WTR, particularly the Fe/Mn-Al-WTR, for the remediation of Cu and Pb contaminated soils and recommend field scale verification.

Growth Response of Blue Panic Grass (Panicum antidotale) to Saline Water Irrigation and Compost Applications, Farrag, Karam, Abdel Hakim Sara, Abd El-Tawab Amr Ramadan, and Abdelrahman Hamada , Water Science, Volume 35, Issue 1, p.31-38, (2021) AbstractWebsite

A pot experiment was conducted to examine the ability of Blue Panic grass (Panicum anti- dotale) to grow in slightly saline soils (2.40 dS m–1) under different levels of saline irrigation water in the presence or absence of compost. Eight treatments were set up in a randomized block design with five replicates as follows: T1 (Freshwater), T2 (Freshwater + compost at 20%), T3 (Saline water 5000 mg L–1), T4 (T3 + compost at 20%), T5 (Saline water 10000 mg L–1), T6 (T5 + compost at 20%), T7 (Saline water 15000 mg L–1) and T8 (T7 + compost at 20%). Growth parameters of Blue Panic Grass were evaluated at the end of the experimental period as plant and root length, shoot, and root fresh and dry weights, total chlorophyll, and total carbohy- drates. In general, tested Blue Panic Grass appeared to be tolerant to high salt concentrations in irrigation water, and slightly significant differences were found for all the measured para- meters. A remarkable growth increase occurred in plants grown in compost-amended soils, with respect to the unamended soils. The results demonstrate the possibility to stabilize the yield of blue panic grass, an important feed crop in Egypt, irrigated with saline water, which can secure animal feed resources without reducing the already limited freshwater availability.

2020
The Future of Agriculture in Egypt (Version 2.0): Comparative Full Cost Accounting Study of Organic and Conventional Crop Production Systems in Egypt., Saeda, T., Mohamed R., Abdou D., Bakr Hassan Abou, Abdelrahman Hamada, Elaraby Tarek, and Abouleish Helmy , 06, Cairo, p.30, (2020) Abstractthe-future-of-agriculture-in-egypt-study2.pdf

n/a

Changes in Labile Fractions of Soil Organic Matter during the conversion to Organic Farming, Abdelrahman, H., Cocozza C., Olk D. c, Ventrella D., Montemurro F., and Miano T. , Journal of Soil Science and Plant Nutrition , (2020) AbstractWebsite

Organic farming can overcome the environmental consequences of intensive conventional farming. The objective of the work was to investigate the changes in labile soil organic matter (SOM) fractions during the conversion from conventional to organic farming in two Italian sites, namely Foggia (FG) and Metaponto (MT), that differed mainly in initial soil organic carbon (SOC) content. Fields were cultivated with lentil and wheat in rotation and treated with either: i) compost or ii) nitrogen or phosphorus (N/P) fertilizers in three field replicates. The SOM was sequentially fractionated into light fraction (LF), particulate organic matter (POM) and mobile humic acid (MHA) fraction. Isolated fractions were quantified and analyzed for C and N contents. Although total SOC responded to the fertilization treatments, the LF and POM fractions were yet more responsive. The MHA represented on average 15% of SOC at both sites, however, the LF represented only 5–6% of total SOC but was the most responsive to changes in soil management. Compost application contributed significantly greater quantities of LF, POM and MHA than did the N/P fertilizers application. The initial SOC content can play an important role in determining the impacts of introducing organic farming practices on SOM fractions. Although both sites had an initial low SOC content, the MT site, with a lower SOC content, showed a substantial fractional C increments as compared to the FG site.

2019
Future Soil Issues, El-Ramady, Hassan, Alshaal Tarek, Abdelrahman Hamada, and El-Hady Omar , The Soils of Egypt, (2019) Abstract

Soils are among the key resources of sustainable development in Egypt. There would be no development, in any nation, without policies and implementation for soil protection, conservation, and sustainability. This is due to the role soils play in almost all fields, including agriculture and its subsectors (farming of animals and plants to produce food, feed, fiber, fuel, etc.), as well as the industrial sector. Egypt faces, currently, great and serious challenges related to the changes in land use, new challenges for soil sciences scientists. Other important future soil issues include the role of soils in global climate changes mitigation/adaptation, establishment of soil protection law, and enforcing it. To solve emerging soil-related problems in Egypt, potential contributions from soil scientists, policymakers, and society are expected. Therefore, this chapter is an attempt to focus on emerging concern on soil and to suggest suitable solutions under the Egyptian conditions.

Chelate induced redistribution of Pb and Zn fractions in contaminated soils and implications on phytoremediation, Abdelrahman, Hamada , Egyptian Journal of Soil Science, Volume 59, Issue 2, p.145-155, (2019) AbstractWebsite

Lead and Zn contaminated soils, after sewage sludge (SS) or industrial wastes (IW) applications, were incubated with 5 and 10 mmol kg–1 soil of diethylene triamine penta acetic acid (DTPA) and ethylene diamine tetraacetic acid (EDTA) or with 10 and 20 mmol kg–1 soil of citric acid for up to 60 days. Consequently, Amaranthus retroflexus L. and Chenopodium album L. were tested in a chelate-assisted Pb and Zn phytoextraction greenhouse trial. In both incubated soils, the organic (Org) bound Pb increased over the incubation period, simultaneously, with a decrease in the oxide bound (Oxid) and carbonate bound (Carb) Pb fractions. Similar observations was found for Zn fractions during the incubation course of both contaminated soils. The EDTA was more effective in increasing the exchangeable Pb at 40 days of incubation in both soils whereas the DTPA was more effective in increasing the exchangeable Zn at 40 days of incubation. The pot experiment showed that Amaranthus retroflexus L. was more effective than Chenopodium album L. in the phytoextraction of Pb and Zn. The maximum amount of Pb and Zn Amaranthus phytoextracted in a 70-d growth period was 6.5 and 8.2 mg kg–1 soil, respectively, whereas the maximum phytoextracted amounts of Pb and Zn by Chenopodium were 3.9 and 3.5 mg kg–1 soil, respectively. Although EDTA and DTPA was more effective in redistributing metals among their fractions during incubation, higher removal of Pb and Zn was achieved after citric acid by Amaranthus. After environmental and economic evaluation, studied weed species can be used in chelate-assisted phytoremediation to decontaminate Pb- and Zn-contaminated soils.

Influence of crop rotation, tillage and fertilization on chemical and spectroscopic characteristics of humic acids, Mastro, Francesco De, Cocozza Claudio, Traversa Andreina, Savy Davide, Abdelrahman Hamada M., and Brunetti Gennaro , Plos One, Volume 14(6):e0219099, (2019) AbstractWebsite

The changes in soil organic matter composition induced by anthropogenic factors is a topic of great interest for the soil scientists. The objective of this work was to identify possible structural changes in humic molecules caused by a 2-year rotation of durum wheat with faba bean, lasted for a decade, and conducted with different agricultural practices in a Mediterranean soil.
Humic acids (HA) were extracted at three depths (0-30, 30-60 and 60-90 cm) from a Mediterranean soil subjected to different tillage (no tillage, minimum tillage and conventional tillage), crops (faba bean and wheat), and fertilization. The changes in HA quality were assessed by several chemical (ash, yield and elemental analysis) and spectroscopic techniques (solid-state 13C nuclear magnetic resonance, Fourier transform infrared and fluorescence).
The results suggest that the different agronomic practices strongly affected the quality of HA. Smaller but more aromatic molecules were observed with depth, while the fertilization induced the formation of simpler and less aromatic molecules due to the enhanced decomposition processes. Under no tillage, more stable humic molecules were observed due to the less soil aeration, while under conventional tillage larger and more aromatic molecules were obtained. Compared to wheat, more aromatic and more oxidized but less complex molecules were observed after faba bean crop.
The inorganic fertilization accelerates the decomposition of organic substances rather than their stabilization. At the end of each crop cycle, humic matter of different quality was isolated and this confirms the importance of the rotation practice to guarantee a diversification of the soil organic matter with time. Finally, no tillage induces the formation of more stable humic matter.

2018
Bias in aggregate geometry and properties after disintegration and drying procedures, Siebers, Nina, Abdelrahman Hamada, Krause Lars, and Amelung Wulf , Geoderma, 2018/3/1/, Volume 313, p.163 - 171, (2018) AbstractWebsite

Isolation and drying soil microaggregates and their building units are of crucial importance when studying their structure and function within different soil management systems. Our aim was to evaluate how different drying techniques preserve small aggregate building units after different disintegration steps. After applying fast wetting, slaking, or ultrasonic dispersion at 440 J mL− 1 to Cambisol topsoils under either long-term forest, grassland, or arable soil management, aggregate-size distributions were assessed using fast image analyses after optical particle-size assessment prior and after air- and freeze-drying. Microaggregates isolated by dry-sieving served as control. While ultrasonic dispersion significantly disintegrated soil aggregates into smaller units, slaking in water did not. Intriguingly, freeze-drying preserved the aggregate size distribution fairly well, with a reaggregation ranging between 1.2 and 10.1%. In contrast, air-drying led to substantial reaggregation of particles ranging between 20.4 and 44.9%. However, freeze-drying also led to slight deformation of particles and also to a redistribution of elements between size-fractions, the extent of which being different for the samples under different land-use. We conclude that ultrasonic treatment followed by freeze-drying is suitable to preserve the correct aggregate size of at least Cambisols, but the properties of the secondary particles may still not reflect true geometric forms and chemical properties.

Historical charcoal additions alter water extractable, particulate and bulk soil C composition and stabilization., Abdelrahman, Hamada, HOFMANN Diana, BERNS Anne E., Meyer Nele, BOl Roland, and Borchard Nils , Journal of Plant Nutrition and Soil Science, Volume 181, Issue 6, p.809-817, (2018) AbstractWebsite

The objective of this work was to investigate the chemical composition and the quantitative changes in soil organic matter (SOM) fractions in response to multiple historical inputs of charcoal that ceased >60 years ago. The topsoil (0–5 cm) and subsoil (5–20 cm) samples of charcoal enriched soils and the unamended reference soils were assessed for C and N contents in bulk soil, particulate organic matter (POM) fractions and water extractable organic matter (WEOM). The SOM molecular characteristics were investigated in the solid phase by nuclear magnetic resonance (NMR) and in the WEOM by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Formerly added charcoal additions reduced the extracted amount of WEOM and altered POM pattern: an increased proportion of C and N stored in coarse, intermediate, and fine POM relative to corresponding total C and N was found in subsoils. In contrast, C and N stored in the residual fraction (<20 µm) decreased. NMR results revealed a higher aromaticity of SOM in charcoal enriched soils, while the FT-ICR-MS results indicated an increased presence of lignin- and tannin-like compounds in the WEOM of these soils. Former charcoal additions enhanced soils capacity to retain and stabilize C and N. Particularly, the presence of charcoal particles elevated C and N stored in large POM fractions >20m, which presumably increases soil porosity and thus the soils’ capacity to retain water.

2017
Precision farming for sustainable intensification of cropping systems in Egypt, Abdelrahman, Hamada, Borchard Nils, and Schirrmann Michael , DAAD Alumni Seminar 2017, 8 Nov., Göttingen, (2017) Abstract

The economic, political and geographic changes that occurred lately in Egypt depleted farmland in the valley and delta of the Nile river. The two main problems that causes farmland depletion are the urban sprawl and the expected shortage in Egypt water share of the Nile water due to the ongoing construction of the Ethiopian dam. Accordingly, it is the role of decision makers, supported by scientists, to introduce solutions to the farming system to optimize the use-efficiency of available land and water resources for sufficient food production. Several measures can be taken to ensure food security in Egypt including cultivation of strategic crops in neighboring countries as has been already done, e.g. Egypt-Zanzibar farm. However, it is necessary to take effective management measures for farming land in Egypt. The on-site solutions are limited to the use of precision farming tools to maximize the productivity per unit area and unite volume of land and water, respectively. The use of unmanned aerial vehicle (UAV) has proven successful in establishing sustainable intensification of cropping systems in other African countries, e.g. Ghana, which suggests the urgent need to implement it in Egypt.

Carbohydrates and Amino Compounds as Short-Term Indicators of Soil Management, Abdelrahman, Hamada, Cocozza Claudio, Olk Dan, Ventrella Domenico, and Miano Teodoro , CLEAN - Soil Air Water · October 2016, Volume 45, Issue 1, p.1–8, (2017) AbstractWebsite

The objective of this work was to evaluate the suitability of carbohydrates and amino compounds in soil and soil organic matter (SOM) fractions to depict the management‐induced changes in soil over short‐term course. Soil samples were collected from two experimental fields managed according to organic farming regulations and a sequential fractionation procedure was applied to separate the light fraction (LF), particulate organic matter (POM), and mobile humic acid (MHA). Contents of carbohydrates and amino compounds were determined in soil and correspondent SOM fractions. Over a 2‐year course, carbohydrate contents decreased in the LF fraction while it increased noticeably in the POM and slightly in the MHA fractions leading into questioning whether decomposing materials get incorporated into older fractions. Amino N content constituted up to 30% of total soil N, with a major contribution of the humic fraction (MHA). Although the LF, POM, and MHA fractions showed the greatest amino N content after the compost‐legumes combinations, the carbohydrate and amino N contents in the POM and MHA fractions of the unamended soil increased as large as the corresponding fertilized plots, underlining that conservative soil management results in accumulation of labile forms of soil C and N that consequently might build up soil fertility. The changes after different treatments suggest the suitability of carbohydrates and amino compounds as short‐term indicators for soil management.

Growth Responses of Organic Tomato Seedlings to N Liquid Fertilizers and Compost-Amended Growing Media, Abdelrahman, Hamada, Ceglie F., Awad FA, and Tittarelli F. , Compost Science & Utilization, Volume 25, Issue 1, p.62–69, (2017) AbstractWebsite

This work evaluated the response of organic tomato seedlings to locally produced compost-amended growing media and commonly used N liquid fertilizers. Green (GC) and mixed (MC) composts were used in growing media formulation with 70, 45, 20, and 0% (control based on peat) on volume basis for organic tomato seedling growth. Three locally available N liquid fertilizers, hydrolyzed-protein-based fertilizer (HP), blood-meal-based fertilizer (BM), and algae-extract-based fertilizer (AE), were tested. Seedlings were evaluated 34 days after sowing for plant height; stem diameter; shoot weights; sturdiness index; specific leaf area; and N, P, and K contents in the seedlings shoot. The statistical analysis showed that the substrate type, fertilizer, and their interaction significantly (p ≤ 0.05) affected, in most cases, the seedlings growth. The compost, especially with 20 or 45% amended substrate, produced longer seedlings with thicker diameter, greater fresh and dry weights, and greater leaves number compared to the control (compost-free) substrate. The use of the HP or the AE fertilizer generally contributed to better seedlings growth than did the BM-based fertilizer. The HP fertilizer clearly affected (p ≤ 0.01) the seedling diameter, fresh weight, and leave numbers while the AE fertilizer affected clearly seedling sturdiness index. The use of the GC or MC compost complemented with the HP or the AE fertilizer successfully reduced up to 45% of peat use in growing media and produced robust organic tomato seedlings.

2016
Effects of Recent Forest Clearcut on Particulate Organic Matter, Abdelrahman, Hamada, WIEKENKAMP Inge, BERNS Anne E., UNGER Kirsten, LEHNDORFF Eva, HOFMANN Diana, KUZYAKOV Yakov, and BOl Roland , The 18th International Conference of the International Humic Substances Society, Kanazawa, Japan, (2016) abdelrahman_etal2016l_1145.pdf
Historical charcoal additions potentially improve stability of soil organic carbon due to altered particulate carbon fractions, HOFMANN, Diana, Steffen Bernhard, Abdelrahman Hamada, Disko Ulrich, and Borchard Nils , The 18th Conference of the International Humic Substances Society, , Kanazawa, Japan, (2016)