N. Patel and T. Rajput, “Effect of fertigation frequency on onion (Allium cepa) yield and soil nitrate-nitrogen”, Indian J Agri Sci, vol. 75, no. 11, Nov. 2005, Accessed: Oct. 27, 2025. [Online]. Available: https://epubs.icar.org.in/index.php/IJAgS/article/view/9271