The current research was carried out in 2016 to evaluate potassium 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 of equilibrium activity ratio of potassium (ARko) ranged between 0.0071 (soil 3) to 0.0320 (mol/L)1/2 (sample no. 1). The labile K (-ΔK0) 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 (PBCK) of soil ranged from 0.964 to 12.86 [(Cmol kg-1/(mol L-1)0.5]. Generally, the highest value of ARko, ΔK0, PBCK 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 ARko 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 (-ΔK0) and both exchangeable Ca and Mg (r=0.936 and 0.941, respectively). The PBCK showed a positive significant correlation with clay content, available K and cation exchangeable capacity (CEC), and negative significant correlations with soil pH (r=-0.795) and CaCO3 (r=-0.633).

A batch experiment was conducted to study the effect of pH on the sorption of copper (Cu), cadmium (Cd), zinc (Zn), and nickel (Ni) by cement kiln dust (CKD). The experiment was carried out by adding 25 mL of solutions containing concentrations of 200, 400, 600, 800, and 1000 mg/L of each of these heavy metal cations to 1.00 g of CKD. The pH of these suspensions was adjusted to 2, 5, and 7 as well as non-adjusted. The sorbed amount (Cs) and the sorption percentage of Cu, Cd, Zn, and Ni by CKD increased with increasing the suspension pH. The adsorption data of Cu, Cd, Zn, and Ni were generally well correlated with Langmuir model when the suspension pH was adjusted to 5, 7, non-adjusted and 7, respectively. However, they could be well described by Freundlich model when the suspension pH was adjusted to 5, 2, non-adjusted and 5, respectively.

A batch experiment was conducted to study the effect of pH on the sorption of copper (Cu), cadmium (Cd), zinc (Zn), and nickel (Ni) by cement kiln dust (CKD). The experiment was carried out by adding 25 mL of solutions containing concentrations of 200, 400, 600, 800, and 1000 mg/L of each of these heavy metal cations to 1.00 g of CKD. The pH of these suspensions was adjusted to 2, 5, and 7 as well as non-adjusted. The sorbed amount (Cs) and the sorption percentage of Cu, Cd, Zn, and Ni by CKD increased with increasing the suspension pH. The adsorption data of Cu, Cd, Zn, and Ni were generally well correlated with Langmuir model when the suspension pH was adjusted to 5, 7, non-adjusted and 7, respectively. However, they could be well described by Freundlich model when the suspension pH was adjusted to 5, 2, non-adjusted and 5, respectively.

Biochar (B) application to sandy soils improves its productivity and mitigates climate change. A pot experiment was conducted to investigate the potential effects of maize stalks biochar applied to a zucchini (Cucurbita pepo L. var. Hybrid fadwa) grown on a calcareous sandy soil. Plastic pots were filed with three kilograms of the studied soil and amended by the biochar at levels of 0 (control, unamended soil), 6.3 (B1), 12.6 (B2), and 25.5 (B3) g pot‒1. The pots were planted with zucchini plants and designed in a complete randomized design with three replications. Amending the soil with the biochar significantly increased the soil organic matter, fresh fruit yield, nitrogen use efficiency (NUE) and agronomic efficiency of applied nitrogen (AEN) of zucchini plants. Biochar additions improved the fresh fruits by 26.7, 55, and 195.0% for B1, B2 and B3 treatments respectively, over the control. The NUE of the plants increased owing to the application of biochar to the soil from 69.2 mg fruit/mg N at the control treatment to 77.1, 84.3 and 131.4 mg fruit/mg N for B1, B2 and B3 treatments, respectively. So, it is recommended to apply biochar as an amendment to the calcareous sandy soil in order to improve its fertility.

Biochar (B) application to sandy soils improves its productivity and mitigates climate change. A pot experiment was conducted to investigate the potential effects of maize stalks biochar applied to a zucchini (Cucurbita pepo L. var. Hybrid fadwa) grown on a calcareous sandy soil. Plastic pots were filed with three kilograms of the studied soil and amended by the biochar at levels of 0 (control, unamended soil), 6.3 (B1), 12.6 (B2), and 25.5 (B3) g pot‒1. The pots were planted with zucchini plants and designed in a complete randomized design with three replications. Amending the soil with the biochar significantly increased the soil organic matter, fresh fruit yield, nitrogen use efficiency (NUE) and agronomic efficiency of applied nitrogen (AEN) of zucchini plants. Biochar additions improved the fresh fruits by 26.7, 55, and 195.0% for B1, B2 and B3 treatments respectively, over the control. The NUE of the plants increased owing to the application of biochar to the soil from 69.2 mg fruit/mg N at the control treatment to 77.1, 84.3 and 131.4 mg fruit/mg N for B1, B2 and B3 treatments, respectively. So, it is recommended to apply biochar as an amendment to the calcareous sandy soil in order to improve its fertility.

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The genetic relationship among twelve Musa accessions was assessed using male flower descriptors and two molecular markers: sequence related amplified polymorphism (SRAP) and amplified fragment length polymorphism (AFLP). Both systems were able to discriminate among accessions by showing good separation based on cluster analysis and by generating several unique markers for certain genotypes. The similarity matrices generated by the molecular markers presented a highly significant correlation and both molecular markers were significantly correlated with the morphological data. Among the male flower descriptors, the compound tepal basic colour was cream or white in Musa acuminata (A-genome) accessions, pink in M. balbisiana (B genome) and yellow in Musa ornata and Musa schizocarpa. Moreover, the compound tepal pink pigmentation was unique in all accessions having the B-genome (M. balbisiana, diploid (AB) and triploid (AA and ABB) hybrids), while both yellow-tinted free tepal and white ovary basic colour were distinct for M. ornata and M. schizocarpa. On the other hand, SRAPs and AFLPs showed several specific bands for certain accessions, with 31 and 25 bands, respectively, specific for M. ornata, and 8 and 25 bands, respectively, specific for M. schizocarpa. In addition, 2 and 4 bands were common between M. ornata and M. schizocarpa, and 9 and 4 shared among accessions having a B-genome: M. balbisiana, and triploid and diploid hybrids (AB and ABB, genomes), generated by each of the two markers, respectively. These specific markers for morphological and molecular descriptors are very important and could be helpful in Musa genotyping and genetic diversity assessment.