srjalsSRJALSSRJALS2788-9386https://doi.org/10.47310/srjals.2025.v05i01.002Effect of Splitting the Dose of Phosphate Fertilizers on Phosphorus Availability and Growth and Yield of Cauliflower (Brassica oleracea var. Botrytis)A field experiment was carried out at the Agricultural Research Station College of Agriculture, University of Basra in southern Iraq. It included the response of cauliflower plants to the addition of 60 kg Pha-1 in the form of Concentrated Superphosphate (CSP) or Diammonium Phosphate (DAP) fertilizers with four treatments of splitting the level of fertilizer: addition all Fertilizer dose at Transplanting (T1); 50% of the fertilizer level at transplanting and remaining 50% divided into three doses, 10 days apart (T2); 50% of the fertilizer level at transplanting and remaining 50% divided into two doses, 15 days apart (T3); 50% of the fertilizer level at transplanting and remaining 50% is added 30 days after planting (T4). Drip irrigation was used to irrigate the plants grown on bands 0.5m wide and each plot 2m long, containing 5 plants. Each treatment was repeated in three replicates with randomized complete block design. Results showed that the type of phosphate fertilizer did not affect soil pH, but affected the soil salinity; salinity increased in the presence of CSP over DAP. Likewise, Type of phosphate fertilizer had a significant effect on available phosphorus in soil, as DAP fertilizer outperformed CSP at a rate of 97.94 and 83. 63 mg kg-1, respectively. This result significantly affected the superiority of DAP on CSP in plant growth parameters (P in leaves, number of leaves plant-1 and leaf area) and in terms of plant yield and quality (head weight, head diameter, total yield, total dissolved solids, carotene in fruits). For the splitting fertilizer level, T3 treatment surpassed the rest of treatments in available phosphorus in soil, growth parameters and yield parameters and quality of cauliflower plants; total plant yield reached 54.37 and 54.20 tons ha-1 with DAP and CSP fertilizers, respectively, with an increase percents of 22.53 and 37.59% compared to the conventional Treatment (T1).