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A two-year experiment (2018 and 2019) was conducted to investigate the conjoint effect of applying rice straw as a soil mulch and treating snake cucumber (Cucumis melo var. flexuosus) plants by potassium silicate solution (4 mM) either by soaking seeds or by foliar applications for different periods, on soil fertility, vegetative growth and yield traits, antioxidant activities in plant, nutrient uptake, and total yield under heat stress conditions. The experiment was conducted during summer season (the maximum weekly temperature ranged from 35.8 to 40.6°C) on a clay soil at Dokki field under greenhouse conditions, Giza governorate, Egypt. The treatment of T5 (soaking seeds for 24 h in potassium silicate solution) combined with covering soil with rice straw gave superior effects on enhancing soil fertility and nutrient uptake, increasing chlorophyll content, increasing antioxidant enzymes activity, decreasing proline and other free amino acids (FAA), total soluble salts (TSS), and vitamin C content, and these were probably the reasons that increased the plant tolerance to face the stress. Total yield increased by 13.4 and 8.19% under rice straw soil cover. Also, its highest values were achieved by the treatment of T5 (173 and 200%), during the two tested seasons, respectively. Results of this study suggest that the conjoint effect of using rice straw as a soil cover and treating plants with potassium silicate solution (4 mM) by soaking their seeds for 24 h is beneficial for improving soil fertility, nutrient uptake as well as for crop production under heat stress conditions. [ABSTRACT FROM AUTHOR]

Three extractions were used to assess the availability of micronutrients in different soil collections. The suitability of some extractions under the conditions of Egyptian soils will be discussed. Three extraction methods (Mehlic 3, Soltanpour and Kelowna) were used for the determination of available Fe, Zn, Mn, Cu and B content of the soil samples (sand, calcareous and clay) during 2020 season. Surface soil samples (0-30 cm) were collected from three sites of Al Boston area in the new Nobaria, Governorate, Egypt, during 2020 season. From each selected plot, ten points were selected in a zig-zag path. The results revealed that the highest values of available Fe, Zn and Cu were given with the extraction solution of Soltanpour, while the highest values of available Mn and B were given with the extraction solution of Mehlic 3. On the other hand, the results showed that clay soil recorded the maximum available Fe, Zn, Mn and Cu, while calcareous soil recorded the maximum available boron content. The interaction between different extraction methods and soil samples was highly significant during 2020 season. [ABSTRACT FROM AUTHOR]

The symbiotic and competitive performances of two highly effective rhizobia nodulating French bean P. vulgaris were studied in silty loam and clayey soils. The experiments were carried out to address the performance of two rhizobia strains [CE3 and Ph. 163] and the mixture thereof with the two major cultivated bean cultivars in two soil types from major growing French bean areas in Egypt. Clay and silty loam soils from Menoufia and Ismailia respectively were planted with Bronco and Giza 6 phaseolus bean cultivars. The data obtained from this study indicated that rhizobial inoculation of Giza 6 cultivar in clayey soil showed a positive response to inoculation in terms of nodule numbers and dry weight. This response was also positive in dry matter and biomass accumulation by the plants. The inoculant of strain CE3 enhanced plant growth and N-uptake relative to Ph. 163. However, the mixed inoculant strains were not always as good as single strain inoculants. The competition for nodulation was assessed using two techniques namely fluorescent antibody testing (FA) and REP-PCR fingerprinting. The nodule occupancy by inoculant strain Ph. 163 in both soils occupied 30–40% and 38–50 of nodules of cultivar Bronco. The mixed inocula resulted in higher proportions of nodules containing CE3 in silty loam soil and Ph. 163 in clayey soil. The native rhizobia occupied at least 50% of the nodules on the Bronco cultivar. For cultivar Giza 6, the native rhizobia were more competitive with the inoculant strains. Therefore, we suggest using the studied strains as commercial inocula for phaseolus bean. To cite this article: H. Moawad et al., C. R. Biologies 327 (2004). [Copyright &y& Elsevier]