| 1 | 1. Delate, K. 2003. Fundamentals of Organic Agriculture. Extension and Outreach Publications. Book 49. |
| 2 | 2. Rana, S.S. 2011. Organic Farming. Department of Agronomy, College of Agriculture, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur, pages. 90p |
| 3 | 3. Elena, B., robyn, B. Soil Science |
| 4 | 4. Nyle, C. B., The nature and properties of soil. Tenth edition |
| 5 | 5. Keith, R. B., Soil Fertility on Organic Farms. Published by North Carolina Cooperative Extension Service |
| 6 | 6. Edward J. Plaster, Soil Science and management. Sixth edition |