Which of the following statements is/are true? Statement A: Green manure refers to the practice of growing and incorporating specific crops into the soil to improve its fertility. Statement B: Green manure crops are typically fast-growing and nitrogen-fixing, helping to increase soil nitrogen levels. Statement C: Green manure crops do not fix atmospheric nitrogen. 

Green manure involves the practice of growing specific crops, often legumes or cover crops, and incorporating them into the soil while they are still green and actively growing. This practice helps to improve soil fertility and organic matter content. Green manure crops, particularly legumes, have the ability to fix atmospheric nitrogen through symbiotic relationships with nitrogen-fixing bacteria in their root nodules. When these crops are incorporated into the soil, they release nitrogen, increasing soil nitrogen levels and benefiting subsequent crops. Green manure crops fixes the nitrogen which helps in the growth of succeeding crop.