Jayasinghe, C.K.Parker, C.A.Kulasooriya, S.A.2012-06-252012-06-251989Journal of the Rubber Research Institute of Sri Lanka69pp.37-47https://dl.nsf.gov.lk/handle/1/8958Diurnal fluctuations in nitrogenase activity (acetylene reducing activity) have been observed in several nitrogen fixing systems. All experimental plants viz. P. phasides D. ovalifolium and M. invisa demonstrated diuanal rhythm withlight intensity. The lowest acetylene reduction activiteswere detected around midnight and they were activelyu fixing nitrogen by 8.00 am. M. invisa responded to high soil temperature in addition to light intensity. A marked drop in acetylene reduction activity was observed by about 4.00pm when the soil temperature was around 38ºCAgriculturePuerariaDesmodiumMimosaLegumesNitrogen fixationAcetylene reductionSoil temperatureLight intensityCover cropsArticle