Enhancing cotton crop productivity in calcareous soils through microbial inoculation and algae extract foliar spray

Abstract

During the 2020 and 2021 summer planting seasons, a field trial was conducted at the Nubaria Research Station, Cotton Research Institute, and Agricultural Research Center. This study aimed to evaluate the effects of bio-fertilization on cotton crop yield, its components, and fiber properties in Giza 94 and Giza 96 cotton cultivars. Utilizing a split-plot experimental design, genotypes ( Extra Giza 96 and Super Giza 94) were assigned to the main plots and bio-organic fertilizer treatments were randomly assigned in four replicates of sub-plots. The experiment involved seed inoculation with Bacillus megaterium, Bacillus circulans, Azospirillum brasiliense, or a mixture of these, followed by foliar spraying with algae extract at 65, 85, and 105 days after planting. Additionally, each treatment received half the recommended mineral fertilizer dose. The experimental soil was made of Calcareous Soils, which were 0 cm to 40 cm. The pH was 8.0 and 7.9, the electrical conductivity was 1.69 and 1.75 dS m−1, and the CaCO3% was 21.14 and 20.89 g/kg soil in the 2020 and 2021 seasons, respectively. Key findings reveal that Giza 94 outperformed Giza 96 regarding growth and yield attributes, while Giza 96 exhibited superior fiber properties. Notably, the combination of bacterial inoculation, algae extract application, and 50% NPK fertilizer resulted in the highest crop yield and fiber quality compared to 100% NPK fertilizer. Nevertheless, the interaction between cotton genotypes and fertilizer treatments showed no significant impact on plant height, the number of fruiting branches per plant, boll weight, and seed index across both growing seasons. From all the results, we recommend using bio-fertilization for Egyptian cotton genotypes (Giza 96 and Giza 94), which means using clean fertilizer, which reduces soil and air pollution.