The study looked at how the timing of nitrogen fertilizer application affects cotton yield and profit. By testing different application times, researchers found that the best timing was a mix of base, seedling, bud-flower, and flower-boll fertilizers. This timing led to higher cotton yield and profit compared to not using nitrogen fertilizer. The efficiency of nitrogen use was also improved with this timing. Applying the same amount of nitrogen in two doses did not significantly affect yield or profit, but it did decrease nitrogen uptake efficiency.