Apply with sulfur for each 10kg DAP you may add 1kg pure sulfur

Applying sulfur is the safest way for results. Acidification occurs faster when the application is incorporated into the soil, not on the surface. Note that delay would occur when soil is not aerated and moist enough for the bacteria to form sulfuric acid.

Apply the P-fertiliser in solution not as solid

Please see the following paper available on Researchgate.

Strategies and methods for improving phosphorus acquisition and its use efficiency:A review

DOI:10.36953/ECJ.021887-5153 Feb 2022

For efficient P use by crop plants soil pH need to be adjusted to near 6.5-7.5 by applying amendments both organic and inorganic. Fertilize P application rate should be based on soil tests. Placement of P below the seed is preferred over broadcast application to avoid P losses by erosion. Other nutrients like N and K should be applied along with P. Organic manures and green manure application enhances P use efficiency.

Acidify the rhizosphere by fertilizing with ammonium based fertilizes. The plant maintains an equilibrium through deprotonation, causing the pH in the rhizosphere to drop by at least 1 pH-point.

Phosphorus use efficiency can also be improved by adopting good agronomic method such as right amount of P fertilizer, at right time, in right place, to right crop. Such methods would prolong and increase the productive use of P in photosynthesis and have nutritional and environmental benefits.