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A pot experiment was conducted under greenhouse condition at the Experimental Farm, Faculty of Agriculture, Zagazig University, Egypt. The experiment aimed to study the effect of different potassium sources (potassium sulphate and potassium feldspar) at the recommended rate (40 mg K kg-1) either single or in combination with soil amendments i.e., farmyard manure (FYM) and sulfur (S) with or without silicate dissolving bacteria (SDB) on yield and nutrients uptake by wheat through the investigated clayey soil. Soil were taken from the surface layers (0-30 cm) from Hehia District, Sharkia Governorate, Egypt. Application of K-sulphate or K-feldspar as individual application or combined with different soil amendments under SDB gave increase in straw and grain yield, potassium uptake, biological yield, 1000 grain weight and protein content of wheat plants compared to untreated soil. The highest value for each of yield, K-uptake and available K was found in clayey soil treated with K-sulphate combined with FYM plus S in the presences of SDB, while the lowest ones were obtained with untreated soils in absence of soil amendments and SDB. Application of Ksulphate showed greater value in each of yield, protein content, K-uptake by wheat plants and soil available potassium than K-feldspar. Application of SDB to K-sulphate or K-feldspar increased yield, protein content, K-uptake of wheat and available potassium compared to the untreated ones. [ABSTRACT FROM AUTHOR]

Soil carbon sequestration is a riskier long-term strategy for climate mitigation than direct emissions reduction as it plays a main role in closing carbon emission gaps. Mangrove ecosystem is a natural wetland that allocated at Red Sea and extended for 500 km at the Egyptian western coast. Five sampling sites were investigated at the north near to the city of Hurghada beginning from the Abu Monquar Island (27° 12′ 58′′N, 33° 52′ 34′′E). This work investigates the impact of the original population of Mangrove type (Avicennia marina) on the soil carbon sequestration. Obtained results of the mean values of measured soil bulk density (SBD) at the soil surface (0-30 cm) were revealed that the lowest values of the SBD was at Abu Monquar Island with 1.31± 0.02, g cm-3 and at Safaga with 1.53 ± 0.05 g cm-3 . While at El Gouna 1, 2 and at Hurghada the SBD values varied from 1.63 to 1.75 g cm-3 . In addition, the soil dry bulk density at the control site (beach without plants) was 1.75± 0.05g cm-3 . On the other hand, the highest values of the Calcium carbonate were obtained Abu Monquar island with 168.20 gKg-1, while the Calcium carbonate values were 26.60 gKg-1, 69.30 gKg-1, 58.50 gKg-1, 91.90 gKg-1 and 26.90 gKg-1 for Gouna1, Gouna2, Hurghada, Safaga, and the control, respectively. The mean values of measured soil organic carbon pool (SOCP) at the soil surface (0- 90cm) revealed that the lowest values of the SOCP was at Hurghada with 8.81± 0.12 Mgha-1 and the highest values at Abu Monquar island with 59.75 ± 0.15 Mgha-1 . While at El Gouna 1, 2 and at Safaga the SOCP values were 14.48, 12.86, and 39.98 Mgha-1, respectively. In addition, the SOCP at the control site (beach without plants) was 6.62± 0.25 Mgha-1 . Thus the Mangrove ecosystem has a great potential to sequestrate the soil organic carbon and reduce the atmospheric CO2. [ABSTRACT FROM AUTHOR]