Multivariate interpretation of the distribution of nitrogen-fixing blue-green algae in rice soils in central Sri Lanka

Abstract

The ecology of nitrogen fixing blue-green algae in rice fields of Central Sri Lanka was studied using multi-variate techniques of analyses. In this study 73 strains of heterocystous blue-green algae, belonging to 21 genera were isolated and the distribution of the 46 most abundant strains was examined in relation to ecological parameters.Besides pedological factors such as pH, water holding capacity and available phosphorus; environmental factors including rainfall and altitude have shown up as parameters influencing the distribution of the algal species. On the other hand, soil organic carbon, total nitrogen, potassium and calcium, do not appear to play an important role in determining the composition of the algal flora.While certain algal species were ubiquitous in their distribution some were restricted, and a few even showed a tolerance to stands with low soil pH and low levels of phosphorus. The agronomic potential of such species is of value especially in relation to rice-growing soils of this District, where low pH and low levels of phosphorus are major limiting factors for the profuse growth of blue-green algae. © 1981 Annals of Botany Company.