Accurate estimation of how much water rapeseed plants need is crucial for proper irrigation. A study was conducted to figure out the water needs of rapeseed by using different models and a special device called a lysimeter. The researchers found that the Penman-Monteith and Priestly-Tailor models gave the most accurate estimates of water use by rapeseed. These models showed less than 10% difference between estimated and actual water use. The study also determined that the crop coefficients for different growth stages of rapeseed were 0.83, 1.20, and 0.65 for Penman-Monteith, and 0.70, 1.05, and 0.55 for Priestly-Tailor. This information can help farmers manage their irrigation water more efficiently for growing rapeseed.