EFFECT OF WEED COMPETITION PERIODS ON THE GROWTH AND YIELD OF BLACK SEED (Nigella sativa L.) Abrar Hussain Athar Nadeem Imran Ashraf Masood Awan DOI: https://doi.org/10.28941/pjwsr.v15i1.269 PDF Published 2009-03-01 Issue Year 2009, Volume 15 , Issue 1 Section Articles