Farklı pH’ya sahip topraklarda fosforlu gübrelerin organik materyaller ile birlikte kullanımının toprağın fosfor fraksiyonlarına etkisi

The increasing global demand for food and agricultural production highlights the importance of sustainable soil and nutrient management. Nutrient bioavailability in soils is influenced by various properties, especially pH. This study investigates the effects of phosphorus fertilizers (TSP and Ground Phosphate (GP)) at 60 mg P₂O₅ kg⁻¹ combined with organic amendments (2% Biochar (B), 4% Vermicompost (V), and 4% Farmyard Manure (FM)) on phosphorus fractions insoils with different pH levels. Changes in phosphorus fractions were assessed through soil incubation experiments and pot trials with maize. In the incubation study, TSP+FM in acidic soils (836 ppm) and GP+FM in neutral (987 ppm) and basic soils (473 ppm) significantly increased total phosphorus (PT). For inorganic phosphorus (PI), the highest content was found with GP+V in acidic soils (114 ppm) and TSP+FM in neutral and basic soils (110 ppm). Similarly, TSP+FM enhanced organic phosphorus (PO) in acidic soils (725 ppm), in neutral soils (928 ppm), and GP+FM in basic soils (410 ppm). In the pot experiment, PT increased with TSP+FM in acidic (726 ppm) and basic soils (421 ppm), while GP+FM was highest in neutral soils (946 ppm). The maximum PI was obtained with GP+V in acidic soils (109 ppm) and TSP+FM in neutral (97 ppm) and basic soils (100 ppm). PO was highest with GP+FM in acidic (654 ppm) and neutral soils (904 ppm), while TSP+B was highest in basic soil (328 ppm). Results indicate phosphorus fractions with soil pH and amendment type, with FM and V significantly enhancing phosphorus bioavailability.