A study was done to see how planting hairy vetch and common vetch after wheat affects crop yields. The results showed that when these green manure crops were ploughed down in the first autumn, they increased the yield of wheat the following year. Decreasing nitrogen fertilizer by 30% led to a small decrease in wheat yield, but planting vetches helped offset this decrease. When nitrogen fertilizer was decreased by 60%, wheat yield decreased more, but planting vetches still helped maintain higher yields compared to no green manure. This shows that planting green manure crops like vetches can improve soil nitrogen levels and increase crop yields.