Response of Blackgram (<i>Vigna mungo</i> L.) Cultivars for Nipping and Graded Levels of Nitrogen for Higher Productivity under Irrigated Conditions oleh Subbaiyan Marimuthu, Koilpitchai Nelson Navamaniraj, Muthuselvan Kathiravan, Palaniyappan Balasubramanian, Udayarpillai Surendran, Salah El-Hendawy, Mohamed A. Mattar