Role of Soil Conditioners in Improving the Soil Physical and Chemical Properties and the Garlic Productivity

Agriculture in Egypt faces increasing challenges related to soil fertility and suitability for crop production, particularly with the growing reliance on marginal lands. Therefore, this study aims to evaluate the impact of certain inorganic soil amendments (bentonite and zeolite), applied alone or in combination with different sources of organic fertilizers (farmyard manure, chicken manure and compost) on improving the physical and chemical properties of a medium-textured soil and their effects on the garlic performance. The results show that applying zeolite, bentonite and organic fertilizers significantly improved the studied soil properties, including enhanced water holding capacity, total porosity, reduced bulk density and improved nutrient retention, as the superior combined treatment was compost+ zeolite. Regarding the plant growth performance (e.g., plant height, leaf area, chlorophyll and NPK) , garlic yield (e.g., bulb diameter and weight, total and marketable yield) and quality (e.g., carbohydrate, vitamin C), the sequence order of inorganic amendments from top effective to less was zeolite followed by bentonite then control, while the sequence order of organic amendments from top effective to less was compost followed by ChM, FYM and control, respectively. Regarding the interaction effect, the superior combined treatment for obtaining the highest values was zeolite x compost. Based on these findings, it is recommended to adopt an integrated soil amendment strategy that combines natural mineral conditioners like zeolite or bentonite with organic matter sources. This approach not only boosts garlic productivity and quality but also contributes to long-term soil fertility and sustainability, especially in the medium-textured soils.