The researchers studied how using biofertilizers and phosphorus affects the growth and yield of Cowpea plants in sandy loam soil. They found that using a combination of Phosphate Solubilizing Bacteria and Vesicular Arbuscular Mycorrhiza, along with a specific amount of phosphorus, led to significant increases in plant height, number of branches, nodules, plant dry weight, crop growth rate, pods per plant, seeds per pod, seed weight, seed yield, and biological yield. This shows that using these biofertilizers and phosphorus can help improve the growth and yield of Cowpea plants in sandy loam soil.