Gunatilaka, M.K.Gunapala, N.Upawansa, G.K.Wijerathnabanda, H.M.2020-09-022020-09-021985Tropical Agriculturist, 141:p.109-119https://dl-doa.nsf.gov.lk/handle/1/2740FERTILIZERSAzollaChemical nitrogen fertilizerRiceAzolla as a partial substitute for chemical nitrogen fertilizer in riceArticle