A rye cover crop can help improve the efficiency of nitrogen use and increase crop yield in vegetable farming. By studying a rotation of broccoli, sweet corn, and root crops over three years, researchers found that the cover crop boosted vegetable productivity and nitrogen levels in the soil for the next growing season. It also enhanced nitrogen use efficiency for the crops. Interestingly, adding more nitrogen fertilizer didn't always lead to higher yields and nitrogen content in the vegetables. The study highlights the importance of managing soil nitrogen levels to match the needs of the crops, with a rye cover crop being a beneficial method to achieve this.