Papers by Prof. Dr. Mahdy H . Hamed
Alexandria Science Exchange Journal, 2020
Two experiments (incubation and greenhouse) were carried out in end of 2018 to evaluate the addit... more Two experiments (incubation and greenhouse) were carried out in end of 2018 to evaluate the addition effect of glauconite rock rates on the release of K and some chemical properties as well as the uptake of potassium by wheat plants of sandy soil. Glauconite mineral rates (0, 3, 6, and 9 g kg-1) were mixed with 300 g (w/w) soil in plastic pot, and then the distilled water was added to the field capacity of soil and incubation for four time periods (0, 30, 60, 90, and 120 days). The results indicated that, glauconite rates resulted in significant increases in the available K of studied sandy soil compared to the control treatment. These increases depended upon the application rate and the time of incubation. Additions of glauconite rates and incubation periods caused increases in most soil K forms (soluble, exchangeable, non-exchangeable, residual of K) of the studied soil samples. Also, soil pH values of treated soils decreased with increasing the applied rate of glauconite and incubation periods. On other side, the soil salinity (EC) and cation exchange capacity (CEC) were increased compared to the control treatment. The dry weight, concentration and uptake values of K were significantly increased with increasing the level of glauconite by wheat plant compared to the control treatment.
Rhizosphere, 2024
The global challenge of food security is threatened by drought stress. Exogenous application of z... more The global challenge of food security is threatened by drought stress. Exogenous application of zinc and amino acids could alleviate the negative impacts of water shortage on the growth, physiological, and biochemical attributes of plants. Based on this hypothesis, a field study was conducted to assess the effects of chelated zinc applied through irrigation systems and foliar amino acids on the growth, physiological and biochemical attributes of corn, under three irrigation levels at the recommended irrigation level (100%), and at 75% and 50% of the recommended rate. The treatments were arranged in randomized complete block design in triplicate. Treatment effects on yield varied with intensity and duration of water stress. An irrigation level of 100% means the normal supply of recommended water. In results, the implementation of irrigation levels on corn led to varying impacts on yield, depending on the intensity and duration of the water stress. Plants responded by reallocating nutrient accumulation within their tissues, which played a crucial role in mitigating the negative effects of water stress. The application of zinc and amino acids individually showed positive effects on corn improvement, as these promoted antioxidant defense systems and enhanced corn yield. However, the combined application of foliar amino acids and soil-applied zinc, particularly under the 75% irrigation level, had a tremendous effect on various examined parameters. There was an increase in catalase by 65.9%, superoxide dismutase by 17.1%, and peroxidase by 15.1%, resulting in improved corn yield by 114.6% and decreased hydrogen
BMC Plant Biology, 2023
In the current industrial scenario, cadmium (Cd) as a metal is of great importance but poses a ma... more In the current industrial scenario, cadmium (Cd) as a metal is of great importance but poses a major threat to the ecosystem. However, the role of micronutrient − amino chelates such as iron − lysine (Fe − lys) in reducing Cr toxicity in crop plants was recently introduced. In the current experiment, the exogenous applications of Fe − lys i.e., 0 and10 mg L − 1, were examined, using an in vivo approach that involved plant growth and biomass, photosynthetic pigments, oxidative stress indicators and antioxidant response, sugar and osmolytes under the soil contaminated with varying levels of Cd i.e., 0, 50 and 100 µM using two different varieties of canola i.e., Sarbaz and Pea − 09. Results revealed that the increasing levels of Cd in the soil decreased plant growth and growth-related attributes and photosynthetic apparatus and also the soluble protein and soluble sugar. In contrast, the addition of different levels of Cd in the soil significantly increased the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2), which induced oxidative damage in both varieties of canola i.e., Sarbaz and Pea − 09. However, canola plants increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and nonenzymatic compounds such as phenolic, flavonoid, proline, and anthocyanin, which scavenge the overproduction of reactive oxygen species (ROS). Cd toxicity can be overcome by the supplementation of Fe − lys, which significantly increased plant growth and biomass, improved photosynthetic machinery and sugar contents, and increased the activities of different antioxidative enzymes, even in the plants grown under different levels of Cd in the soil. Research findings, therefore, suggested that the Fe − lys application can ameliorate Cd toxicity in canola and result in improved plant growth and composition under metal stress.
Environmental Technology & Innovation
Incorporation of crop residues into agricultural system has become a worldwide efficient practice... more Incorporation of crop residues into agricultural system has become a worldwide efficient practice for enhancing crop production. The main objectives of this experiment was to investigate the major role of incorporating wheat (Triticum aestivum L.) residues and nitrogen (N) fertilizers rates under different water requirements (WR) on growth, seed yield and yield components of common bean (Phaseolus vulgaris L.). The results showed that seed yield under 80% WR in retained crop residue plots was 11% higher than WR treatment with no residue incorporation. Seed yield was not significantly different between residue retention and removal treatments in 2016, whereas it was higher (12% and 17%) under residue retained plots compared to removed ones in subsequent years. Seed yields responded to N up to 170 and 225 kg ha−1 in removed and retained residue treatments, respectively in 2017 and 2018. Annual increment of seed yield in residue retained plots (36%) was 2.11 times higher than the residue removed ones (17%). There was higher soil N content in 50% residue retention with 225 kg N ha−1 under both water deficit treatments in all years. The highest soil organic carbon (SOC) was achieved with normal irrigation in retained residue plots with 225 kg N ha−1 in all years. Overall, wheat residue incorporation into the soil and N-supply substantially contributed to counteracting yield declines of common bean under water deficit conditions.
Environmental Technology & Innovation, 2021
Conventional pyrolysis of agricultural wastes may emit considerable amounts of greenhouse gases t... more Conventional pyrolysis of agricultural wastes may emit considerable amounts of greenhouse gases that affect negatively the surrounding environment. A trial was done to capture the emitted gases through connecting a small water jacket with the pyrolysis unit. This plant was then used for production of biochars from two waste materials i.e. nutshell (NS-BC) and date-palm seed (DP-BC). The biochars manufactured from the aforementioned waste materials were then evaluated for their applicability vs pig manure (each amendment was applied at rates of 1, 2.5, 5 and 10%; w/w) to improve growth of Brassica chinensis grown on a sandy soil under greenhouse conditions. Collected liquefied smokes were also tested for enhancing germination of Lactuca sativa (lettuce) seeds using different concentrations (0%–5%, v/v). Results revealed that produced biochars decreased significantly soil pH where the highest reduction (14.30%) was occurred due to addition of 10% DP-BC. Moreover, NS-BC and DP-BC decreased significantly soil salinity from 0.21 dSm ⁻¹ (control) to 0.13 and 0.14 dSm ⁻¹, respectively; on the other hand, pig manure raised significantly soil salinity (10% application rate). Residual organic matter was higher in biochar amended soils than its corresponding values in pig manure treated ones. Generally, all investigated amendments improved considerably the uptake of nitrogen, phosphorus, and potassium. Moreover, they increased chlorophyll pigments in leaves and enhanced plant growth parameters upon their application at rates up to 2.5% with superiority for NS-BC versus DP-BC. Liquefied smoke also impr
Zemdirbyste-Agriculture, 2021
Composting chicken manure causes negative impacts on environmental ecosystem by increasing ammoni... more Composting chicken manure causes negative impacts on environmental ecosystem by increasing ammonia (NH 3) emissions. Split addition of maize straw-derived biochar (Bi) during composting of chicken manure may promote the composting process, increase the quality of produced compost and reduce NH 3 volatilization. To build composting piles, fresh chicken manure and maize straw were mixed (2:1 w/w). Biochar (10% w/w) was applied to the compost piles in different addition modes: one-time applied biochar (OTABi), 10% at the beginning of the trial, and split-applied biochar (SABi), 2.5% at 0, 3, 7 and 15 days of the composting. In addition to the control (without biochar) treatment, measurements of NH 3 emissions were performed in a bench-scale composting experiment. To evaluate the phytotoxicity and maturity of the compost, germination tests were performed in Petri dishes. Compared with the control and OTABi treatments, SABi had a great positive effect (by 40% and 33%) on the final general characteristics of the compost and reduced the cumulative NH 3 emissions. Although OTABi treatment had faster degradation during composting, it did not enhance humification. In the mature compost, the humic substances of SABi treatment were 17% and 40% higher than control and OTABi treatments. In addition, in SABi, the values of humic acid carbon (HAC) and humification index (HI) were significantly higher than in other treatments. By the end of composting, both biochar application modes exhibited low water-extractable organic carbon and high seed germination index compared with the control treatment. This study suggests that during chicken manure composting split application of biochar is a crucial practice for reducing N loss, mitigating NH 3 emissions and enhancing humification.
Environmental Technology & Innovation, 2021
Underground water is the main and probably the only source of drinking and irrigation in New Vall... more Underground water is the main and probably the only source of drinking and irrigation in New Valley Governorate (Egypt). To assess water suitability for such purposes, 30 well-water samples (80-1300m depth) were collected from three oases i.e., El-Kharga, Baris and El-Dakhla. The pH values of these waters ranged from 6.5 to 7.88. SO 2− 4 was the dominant anion in such waters while Ca 2+ was the dominant cation. Concentrations of both ions (SO 2− 4 and Ca 2+) exceeded the maximum allowable limits for drinking and irrigation purposes. Although sodium adsorption ratio (SAR) values did not exceed ''10'' in all waters samples; however, Mg-hazards and low infiltration rate might threaten the suitability of water for irrigation in many locations. Concentrations of Zn, Mn, Cu, Pb, Cd, As and Se were below the maximum allowable concentrations suggested by FAO for irrigation water. On the other hand, Fe was the only potentially toxic element (PTE) whose concentrations exceeded the permissible levels of WHO regulations for drinking water. According to the principal component analysis (PCA), these metals were originated from natural (Fe, Mn, Zn and Cu) and anthropogenic (As, Pb, Cd and Se) sources. Their existence represents potential chronic threats to children, particularly Fe, Mn, Pb and As. Moreover, the majority of water samples were within the moderate grade of irrigation quality index while exhibited low grades for the drinking quality index. Accordingly, more attention should be paid towards improving the quality of underground water in New Valley governorate for either drinking or irrigation purposes.
Ten surface soil samples (0-30 cm) were collected from El-Qasr village, El-Dakhla Oasis, New Vall... more Ten surface soil samples (0-30 cm) were collected from El-Qasr village, El-Dakhla Oasis, New Valley, Egypt to investigate some soil properties and nutrients availability. The results revealed that most of the soil texture varied clay loam to sandy clay loam. The mean values of bulk density (BD), soil pH, electric conductivity (EC), saturation percentage (SP), calcium carbonate (CaCO 3), cation exchangeable capacity (CEC), organic matter (OM), and sodium adsorption ratio (SAR) were 1.42 gcm 3 , 7.89, 3.34 dSm-1, 52.10%, 7.46 %, 28.08 cmol (+) kg-1 , and 3.65, respectively. The mean values of N, P, and K were 99.37, 31.32, 121.93, mg/kg, respectively. Meanwhile, the mean values of Fe, Mn, Cu and Zn were 27.39, 18.38, 0.48, and 3.48 mgkg-1 , respectively. The correlations coefficient of NPK was strongly positively significant relationship with clay, OM, CEC, and SAR, but they negatively correlated with pH, EC, CaCO 3. Meanwhile, Fe, Mn, and Cu were positively correlated with EC, CaCO 3 , while they negatively correlated with clay, pH, OM, CEC, and SAR. Also, Zn was negatively correlated with clay, pH, EC, OM, and CaCO 3 , and it positively correlated with CEC and SAR.
The current research was carried out to evaluate potassium kinetics represented in the Quantity-I... more The current research was carried out to evaluate potassium kinetics represented in the Quantity-Intensity parameters and the relation of these parameters to the characteristics of some agricultural soils of El-Dakhla Oasis, New Valley, Egypt. Six surface soil samples (0-30 cm) were collected from different sites in El-Dakhla Oasis. The values equilibrium activity ratio of potassium (AR k o) ranged between 0.0071 (soil 3) to 0.0320 (mol/L) 1/2 (sample no. 1). The labile K (-ΔK 0) values also, varied from 0.020 (sample no. 4) to 0.412 (cmol/kg soil (sample no.1).The values of the potassium potential buffering capacity (PBC K) of soil ranged from 0.964 to 12.86 [(Cmol kg-1 /(mol L-1) 0.5 ]. Generally, the highest value of AR k o , ΔK 0 , PBC K parameters were related in soil sample no. 1[(0.032 (mol/l) 0.5 , 0.412 cmol/kg, and 12.86 [(cmol kg-1 /(mol L-1) 0.5 ], respectively. The AR k o was a negatively significant correlated with exchangeable potassium (r=-0.822), Organic matter (-0.633) and available K (-0.444). A positive highly significant correlation was obtained between the labile K (-ΔK 0)and both exchangeable Ca and Mg (r=0.936 and 0.941, respectively). The PBC K showed a positive significant correlation with clay content, available K and cation exchangeable capacity (CEC), but it was negatively significant
Thirty-four soil samples were collected from Garb El-Mawhob soils, northwest of El-Dakhla oasis, ... more Thirty-four soil samples were collected from Garb El-Mawhob soils, northwest of El-Dakhla oasis, New Valley governorate, Egypt to evaluate the soil available phosphorus and its relation with the properties of these soils. These samples were taken from the surface (0-30 cm) and subsurface layers (30-60 cm) of 17 soil profiles covered the study area. Most of the soil samples had a texture of loamy sand, sandy clay loam and clay. In most cases, the studied soils showed mild alkaline pH (7.4 to 7.8) values. The electrical conductively (EC e) and Ca-CO 3 of these soils varied from low to high levels and ranged from 1.05 to 163 dS/m and from 2.2 to 57.58%, respectively. The soil organic matter content differed from 0.08 to 2.27%. Also, the soluble cations and anions in most of the studied soils followed the order of Ca +2 >Na + > Mg +2 > K + and Cl-> SO 4 = > HCO 3-, respectively. The cation exchange capacity (CEC) and sodium adsorption ratio (SAR e) of these soils were ranged from 6.58 to 57.49 cmolc/kg and from 0.11 to 45.18%, respectively. The NaHCO 3-extractable soil phosphorus of these soils varied from 2.25 to 65.35 mg/kg in the surface layer and from 3.34 to 24.49 mg/kg in the subsurface one. In general, about 50% of the studied soil samples had a low level of available P (< 6 mg/kg), 24% of them showed a medium level (6-10 mg/kg) and 26% of them contained a high level of available P (>10 mg/kg). Moreover, the studied soil samples that had clay and clay loam textures contained a high level of available P than those having other textures. The available P showed highly significant positively correlation, with some soil properties, such as OM, HCO 3-, CEC and silt contents, while it was negatively correlated with EC e , Na + ,CaCO 3 and Ca +2 .
Restoration of shooting range soils is an emerging environmental issue for nature conservation. A... more Restoration of shooting range soils is an emerging environmental issue for nature conservation. A large number of shooting ranges is present in Egypt without paying attention to controlling the environmental pollution. The main objective of this research was to investigate the integrated effect of applying biochar (BC) derived from sugar cane wastes for soil fertility improvement and lead (Pb) stabilization. To achieve this goal, sugar cane wastes were collected, and used for producing the BC. A small-scale BC production unit was designed by using double metal barrels; thereafter, sugar cane wastes were placed and burned inside the BC producing unit. The produced BC was used to restore the biological function of a polluted shooting range soil by immobilizing Pb and improving the soil fertility. A surface sandy loam soil was collected from a shooting range site in the Giza Governorate-Egypt and was incubated for 365 days with different application levels (0.0, 1.0, 2.5, 5.0, 10.0, 20.0 and 30.0% w/w) of BC. The results showed that the addition of BC significantly increased the soil water holding capacity, available nutrients (N and P) and cation exchange capacity as well as stimulated the microbial growth (bacteria and fungi) in the soil. Moreover, the addition of BC led to a significant decrease in the available Pb fraction by 97.0%, as compared to the untreated soil. The phytotoxicity test revealed that the addition of BC significantly increased maize biomass (shoots and roots), especially with applications of 3% and 5% treatments. However, no plant growth occurred on the untreated soil. Furthermore, Pb uptake by maize plants significantly decreased with increasing the level of applied BC. Our findings provide evidence that BC application decreased Pb toxicity by immobilizing Pb and improving soil quality. Therefore, BC can be effectively used for sustainable development and environmental protection.
A field study was conducted at The Experimental Farm, Fac. of Agric., Al-Azahar University, Assui... more A field study was conducted at The Experimental Farm, Fac. of Agric., Al-Azahar University, Assuit, located 375 km south of Cairo, Egypt (27° 12-16.67= N latitude and 31° 09-36.86= E longitude) through wheat growing season 2015. The aim of current study is to asses the effect of nitrogen fertilizer types (urea and ureaform) at different levels on soil organic carbon decomposition. Soil organic carbon decomposition percentage (SOCD) is at a minimum amount in the 2 nd week and at a maximum amount in the 7 th week at the recommended urea level-15% (R-15%). The biweekly SOCD % varied from 0.82 and 9.55 % at 70 kg N/fed level (R-30%). SOCD% ranged between 0.16-12.73, 5.14-10.61 and 0.41-8.78% for ureaform level at (R-15%) and (R-30%) less than the recommended one (R), respectively. The amount of soil CO 2 flux from recommended ureaform level treatment was the highest one during the entire growing season. Overall, SOCD% followed the order of R > R-15% > R-30%. The highest values of SOCD % were 8.4 and 8.2 at 2.4 Q 10 value with urea and at 2.7 Q 10 value with ureaform, respectively. The lowest values of SOCD % were 2.3 and 4.4 at 2.2 Q 10 value with urea or ureaform, respectively. Soil C: N raties under all treatments were higher than that of initial state except that under R-30% of urea. The soil C: N ratio was higher at R-15% of urea than that when soil treated by ureaform. The opposite trend is true at R-30%.
Experiments were conducted to study the effect of addition solid olive mill waste (SOMW) to calca... more Experiments were conducted to study the effect of addition solid olive mill waste (SOMW) to calcareous soil on phosphorus (P) forms and some chemical properties as well as dry matter and P uptake by wheat plants (Triticum aestivum L.) grown on soil from Wadi El-Assiuti area, Assiut Governorate, Egypt. Rates of SOMW are zero, 10, 20 and 30gkg-1 were mixed with 200g of soil samples and moistened to the field capacity, and then incubated at 30±2ºC for zero, 30, 60 and 90 days. The results indicated that the soil P forms of soluble-P, NaHCO 3-P, NaOH-P, and HCl-P increased with increasing the rate of (SOMW) application, also increases up to 60 days of incubation, then decreased at 90 days. Residual-P form decreased with increasing the rate application, as well as the increase in the time of incubation. The highest of all P forms (except the residual-P one) were obtained at the highest application level. For the soil chemical properties, soil salinity of the studied soil significantly increased. On contrast, the soil pH and calcium carbonate (CaCO 3) decreased with increasing both of SOMW level and the time of incubation. Meanwhile, soil organic matter increased with increasing the level of SOMW, and decreased with increasing the incubation time. Dry mater yield and P uptake by wheat plants grown on the soil decreased with increasing the addition of the waste material.
An incubation experiment was carried out in plastic pots to study the application effects of the ... more An incubation experiment was carried out in plastic pots to study the application effects of the investigated organic materials (Humic acid (HA), Vinase (V), Clover straw (CS), and Ethylene diamin tetra acetic acid (EDTA).) on P forms in calcareous soils. Each organic material was applied to 200g soil at two levels (2.5 and 5.0%) as organic matter. The experiment was carried out for incubation time periods (0, 30, 60, and 120 days). The results indicated that the addition of all investigated organic materials caused increases in most soil P forms (Resin-P, organic-Po, inorganic-Pi, and HCl-P) of the studied soils. These increases in P forms depended upon the type and level of the used organic material, the time of incubation and the soil type. Generally, in all studied soils, the investigated organic materials had the order of Vinasse > HA > CS > EDTA.
Hamed, M. H.*, El-Desoky, M. A.**, M. A. Faragallah*, A. R. Usman, 2011
A pot experiment was conducted to evaluate the effect of a mineral fertilizer (K 2 SO 4 ) and som... more A pot experiment was conducted to evaluate the effect of a mineral fertilizer (K 2 SO 4 ) and some organic amendments (filter mud cake, sheep manure and poultry manure) on potassium (K) forms and availability to sorghum plants (Sorghum bicolor) grown on a calcareous sandy soil. Soil chemical properties (pH, salinity and organic matter) were also investigated.
El-Desoky, M.A., M. A. Faragallah, A. Ghalab and M. H. Hamed, Feb 24, 2010
Four soil samples were collected from the surface layer of some cultivated and uncultivated calca... more Four soil samples were collected from the surface layer of some cultivated and uncultivated calcareous soils located in the areas of Wadi El-Assiut and its interference zone with the Nile valley at Assiut to evaluate the application effects of certain organic materials on some chemical properties and the available Ca and P of these soils. The organic materials included 1) humic acid (HA) 2) vinasse (V) 3) clover straw (CS) and 4) ethyllyene diamine tetra acetic acid (EDTA). They were applied to the soil samples at levels of 2.5 and 5.0%. Soil samples treated with organic materials as well as the controls were moistened to the field capacity and then incubated at 24±2ºC for different time periods (30, 60 and 120 days). up to 30 days and then, decreased in the last two incubation periods (60 and 120 days).
Books by Prof. Dr. Mahdy H . Hamed
management, irrigation, drainage, and salinity management of cultivated areas, collection and
st... more management, irrigation, drainage, and salinity management of cultivated areas, collection and
storage of rainfall in relation to soil properties and vegetation; the role of groundwater and
surface water in nutrient cycling, exploitation and protection of water resources, control of
flooding, erosion, and desertification. This new book presents leading-edge research from
around the world.
Expert Commentary - Eddy covariance technology has been used for crop water use
measurements (evapotranspiration, ET) widely because its operation is relatively simple and
the equipment is less expensive than constructing a lysimeter. However, this technology has
energy closure problems. These problems can be caused by low wind speed, stable
conditions, horizontal flux or/and canopy roughness. In addition, wind sensor leveling, air
humidity, and footprint can affect the ET measurement accuracy. This commentary discusses
how to check ET measurement accuracy and how to measure accurate ET using eddy
covariance technology.
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Papers by Prof. Dr. Mahdy H . Hamed
Books by Prof. Dr. Mahdy H . Hamed
storage of rainfall in relation to soil properties and vegetation; the role of groundwater and
surface water in nutrient cycling, exploitation and protection of water resources, control of
flooding, erosion, and desertification. This new book presents leading-edge research from
around the world.
Expert Commentary - Eddy covariance technology has been used for crop water use
measurements (evapotranspiration, ET) widely because its operation is relatively simple and
the equipment is less expensive than constructing a lysimeter. However, this technology has
energy closure problems. These problems can be caused by low wind speed, stable
conditions, horizontal flux or/and canopy roughness. In addition, wind sensor leveling, air
humidity, and footprint can affect the ET measurement accuracy. This commentary discusses
how to check ET measurement accuracy and how to measure accurate ET using eddy
covariance technology.
storage of rainfall in relation to soil properties and vegetation; the role of groundwater and
surface water in nutrient cycling, exploitation and protection of water resources, control of
flooding, erosion, and desertification. This new book presents leading-edge research from
around the world.
Expert Commentary - Eddy covariance technology has been used for crop water use
measurements (evapotranspiration, ET) widely because its operation is relatively simple and
the equipment is less expensive than constructing a lysimeter. However, this technology has
energy closure problems. These problems can be caused by low wind speed, stable
conditions, horizontal flux or/and canopy roughness. In addition, wind sensor leveling, air
humidity, and footprint can affect the ET measurement accuracy. This commentary discusses
how to check ET measurement accuracy and how to measure accurate ET using eddy
covariance technology.