Nowadays, degraded soils reclamation e.g., sodic soils is the main target for Egypt Government to face the great gap between food production and consumption. The high exchangeable sodium on soil colloids is a plant stress factor due to its role in reducing soil aggregates. To face this challenges, two field experiments were carried out aiming at evaluating the impact of soil amendments as main plots i.e. sugar lime mud and agricultural gypsum, and foliar application of potassium silicate at different rates [0.0 (control), 750 and 1500 mg L-1K2SiO3] as sub-plots on wheat plants grown on soil having ESP value of 15.9%. Both soil amendments improved sodic soil properties, where the superior amendment was gypsum followed by sugar lime mud compared to untreated soil, and this improvement reflected on plant performance. The rate of 1500 mg L-1 K2SiO3 possessed the best performance, while the rate of 750 mg L-1K2SiO3 came in the second-order and lately control treatment. Generally, the best performance of wheat plants grown under sodicity condition was realized when plants were treated with gypsum and potassium silicate at rate of 1500 mg L-1, while the lowest performance was recorded when plants were not treated (without soil and foliar applications). The studied materials enhanced the synthesis of chlorophyll in wheat plant tissues, and this may be the reason for increasing the ability to tolerate sodicity. Also, sugar lime mud has a great opportunity to be included in the fertilization programs for degraded soil especially from an economic point of view.
The present research work discussed the impact of permeate gap region (PGR) on the high mass transfer resistance and low productivity resulted from the air gap region (AGR) sandwiched between the membrane and condensing surface in the air gap membrane distillation (AGMD). Two hollow fiber permeate gap (PGMD) and air gap membrane distillation (AGMD) modules were built, examined, and compared experimentally under several operating parameters such as feed salt concentration (Cf), feed temperature (Tf), coolant temperature (Tc), and flow rate (Mf). The performance comparison was done according to the values of energy consumption (STEC), water productivity (Pw), waste heat (QH.I), and gained output ratio (GOR). Results showed that the PGR was more effective than AGR on the membrane module performance at all investigated operating parameters. Under operating parameters of Cf = 7.5 g/L, Tc = 15 oC, Tf = 70 oC, Mf = 4 L/h, and compared with AGR, the PGR minimized STEC and QH.I by around 78.32% and 47.06%, and improved the Pw and GOR by about 95.93% and 90.33%, respectively. Thus, the negative gap region effect could vanish completely by filling it with the permeated water instead of air, promoting by which the performance of the membrane distillation module remarkably.
This study was carried out in the Sulaimani Governorate, Iraqi Kurdistan Region, to estimate manganese release kinetics in five calcareous soils including (Sharazor, Qaradagh, Bazian, Mawat, and Surdash). The highest amount of Mn release during 48 hours was least in soil Surdash (64.00 mg kg-1), while Soil Mawat exhibited the highest release (541.82 mg kg-1). The value of first order release rate constant (k1) from first order differed from 0.076 to 0.102 with a mean of (0.091 h-1). The mean values of the rate constant (a and b) from the power function model were (2.128 mg Mn kg -1(h-1)b and 0.916 mg Mn kg-1)−1) respectively varied widely with the five soil. The value of second order release constant (k2) from second order model, varied from (-0.012) to (-0.005) with a mean of (-0.008 mg Mn kg-1)-1. The first order, power function, and second order were the best-fitted model used to describe Mn release process very well in the investigated soils.
Soil application of water hyacinth biochar as a source of nutrient- and carbon-rich biomass may be an effective ploy to eradicate this invasive aquatic weed. Incubation trial was conducted to assess effects of water hyacinth biochar addition on some sandy soil biochemical and biological properties and potential carbon sequestration at different application rates and methods. Results demonstrated that pyrolysis of water hyacinth at temperature of 300 °C and 30 min furnace residence time produced biochar with coveted physicochemical properties. Field emission scanning electronic microscopy (FE-SEM) images obtained for water hyacinth biochar showed major macroscopic changes caused by substantial changes in pore structure, surface area and surface morphology due to insufficient carbonization. Soil biochemical and microbiological characteristics after incubation exposed obvious significant improvements at all rates compared to control and varied markedly between addition of biochar as incorporation and broadcasting. Among different treatments, biochar addition as incorporation at the rate of 3% resulted in higher significant increases in most tested soil parameters. Water hyacinth biochar provided nitrogen and carbon immediately via SOC, DOC and DON in treated sandy soils providing energy for microbial biomass compared to control and this reflected by increases in soil values of C-MIC N-MIC and P-MIC. In addition, water hyacinth biocharring would greatly improve sandy soil carbon sequestration at high application rates. It could be concluded that water hyacinth transformation into biochar represents a sustainable strategy for managing these weeds and thus become a valuable organic source for sandy soils and will boost carbon sequestration.