Effect of Adding NPK-Chitosan Fertilizer and Organic Matter on  phosphorus and potassium content of Corn (Zea mays L.). University of Thi-Qar Journal of agricultural research, [S. l.], v. 13, n. 1, p. 146–152, 2024. DOI: 10.54174/utjagr.v13i1.310. Disponível em: https://jam.utq.edu.iq/index.php/main/article/view/310.. Acesso em: 8 sep. 2024.