National Institute of Fundamental Studies

Project Description

The Rhizobium Inoculant Research and Production Project abbreviated as the Rhizobium Project commenced operations at the IFS from January 2012 after moving from the Department of Botany, University of Peradeniya where it was functioning for nearly 10 years. The principal objective of this project is to conduct research and development for the production of rhizobia based inoculants for food and pasture legume crops grown in Sri Lanka. In this manner it is expected to improve biological nitrogen fixation in these crops and minimize the application of chemical nitrogen fertilizer (urea, ammonium sulphate, ammophos etc). The vision of this project is to popularize low cost, environmentally benign, sustainable crop production. In this manner it is expected to reduce the financial burden on the country to import these fossil fuel-based fertilizers as well as minimize environmental pollution that is responsible for several community health problems such as chronic kidney diseases of unknown etiology (CKDu), blue baby syndrome and certain cancers.


Rhizobia are isolated from targeted crops such as Glycine max (soybean), Vigna radiata (mung bean), Vigna unguiculata (cowpea), Vigna mungo (black gram), Phaseolus vulgaris (pole bean), Arachis hypogea (groundnut) etc using selective media. These are purified, authenticated, screened for nodulation and nitrogen fixation and stock cultures of selected strains are maintained in a germplasm. These are semi-mass cultured under sterile conditions (Fig 1) and packeted in sterile, modified coir dust based carrier material (Fig 2) and made available for field use.

The inoculants prepared and marketed by the project for soybean can replace the entire requirement of urea by this crop (Fig 3). Inoculated soybean fields also showed very few weeds (Fig 4). This is because nitrogen fixed by the root nodules is not freely available to other plants like that from chemical fertilizers. Therefore use of weedcides could also be reduced with a concomitant reduction in cost of production as well as environmental pollution. Fixed nitrogen is far less prone to leaching, percolation and other losses and remains stored as organic matter in the crop plants.

Fig 3: Grain yields due to inoculation (yellow line) out performed those due to urea applications

Fig 4: Inoculated soybean cultivation at Madatugama with hardly any weeds

Extension and awareness programs are conducted in collaboration with State organizations, NGOs, CBOs, Pivate sector agri-business companies and farmer groups to introduce and popularize the use of these bio-fertilizers in crop production. Field trials are often conducted in famers’ field by the farmers, under our guidance. This approach has been successful and effective in technology transfer. These activities are run jointly with the Microbial Biotechnology Unit which is engaged in research and development of biofilm-biofertilizers with the common objective of minimizing chemical fertilizer use.

Inoculants for soybean, mung bean, cowpea, black gram and pole bean are currently being field tested in collaboration with the Field Crops Research and Development Institute at Maha Illuppallema and the Regional Research Center at Agunakolapelessa of the Department of Agriculture, in forward contracted farmers’ fields at Mahiyangana in collaboration with Plenty Foods PLC, in farmers’ fields at Madatugama and Maha Illuppallema in collaboration with the Department of Botany, University of Peradeniya and in farmers’ plots at Hanguranketa in collaboration with local farmers coordinated by the Provincial Agriculture officials.

A collaborative project was also initiated with Ambewela Farms PLC to examine and improve nodulation and nitrogen fixation in clover plants (Trifolium purpureum) they have introduced to their pasture lands. By developing suitable rhizobial inoculants it is targeted to increase nitrogen fixation in these pastures and thereby reduce the loading of nitrogen fertilizers to these pristine highland areas that serve as watersheds for all the major rivers of Sri Lanka.

An International Master Class on Root Nodule Bacteria for Sustainable Agriculture was held in November/December 2012 in collaboration with the Center for Rhizobium Studies, Murdoch University of Western Australia. This was held at the IFS primarily due to the reputation of the Rhizobium project and was funded by the Crawford Fund, The Australian Council for International Agricultural Research and the Kirkhouse Trust of U.K. This class conducted by five resource persons from the Murdoch University together with two resource persons from the IFS was attended by 11 participants from 8 different countries of Asia and Africa and 4 participants from Sri Lanka.

Group photo of the Master Class: Resource persons, participants and IFS staff

Research Group

Group Leader -Coordinator and officer-in charge

Prof. S.A. Kulasooriya

curriculum vitae »

Research Assistant

Mr. E. M. H. G. S. Ekanayake

curriculum vitae »

Research Assistant

Mr. R. K. G. Kosala Kumara

curriculum vitae »

Research Assistant

Ms. A. M. G. Dilhara Abeyratne

curriculum vitae »

Achievements of the Project

During the one and a half years of its operations the project has supplied inoculant packets for 11,790 acres of soybean earning a gross income of Rs. 3,370,000/-. As this is a self sustainable project which pays its employees and spends for all its raw material requirements and field trials, the net income from these earnings is in the region of Rs.2.5 million. Field trials so far conducted have given very encouraging results with pole bean and mung bean. Farmers in the Hanguranketa area have shown enthusiasm in using the inoculants for pole bean and the marketing of inoculants for this crop is likely to commence this year. Inoculants for mung bean are targeted to be released next year.

  • S. A. Kulasooriya and Gamini Seneviratne (2012) Transfer of microbial inoculant technology to rural farmers in Sri Lanka. International symposium on Improving the Quality of life Through Science, at the Inaugural General Assembly of the Association of Academies and Societies of Sciences in Asia, 16 – 19, October 2012, Galadari Hotel, Colombo, Sri Lanka: 73 – 77.
  • S. A. Kulasooriya, E. M. H. G. S. Ekanayake and R. K. G. Kosala Kumara (2007) Application of rhizobial inoculants for pulse crop cultivation in Sri Lanka. In: CARP workshop on Agricultural Technologies, May 2007, Council for Agricultural Research Policy.
  • C. S. Hettiarachchi, P. Saravana Kumar, C. L. Abayasekera and S. A. Kulasooriya (2011) Cross inoculating ability of rhizobia from non-edible legumes on Vigna radiata, Vigna mungo and Glycine max. Proc 67th Ann Sessions, SLAAS, Part I, Abstract 417/D: 59.
  • Hettiarachchi C. S., Saravana Kumar, P., Abayasekera, C. L., Ekanayake, E. M. H. G. S., Kumara, R. K. G. K. and Kulasooriya, S. A. (2011) Response of crop Vigna radiata inoculated with rhizobial strains isolated from crop wild relatives of Vigna sp. and Mimosa sp. Proc Peradeniya Univ Res Sessions, 16: 182.
  • Ariyaratne, M. D., Seneviratne, G. and Kulasooriya, S. A. (2011) Comparison of rhizobial inoculants and fungal-rhizobial biofilms on nodulation, N-yield, growth and development of green gram (Vigna radiata). Proc Peradeniya Univ Res Sessions, 16: 186.

Possible future developments

The decision of the Government to restrict the import of soybean to Sri Lanka has led to a rapid expansion of soybean cultivation resulting in an increased demand for rhizobial inoculants. To cater to this requirement the activities of the project need to be increased enormously. The IFS under the advice of the Ministry has therefore decided to form a company in partnership with the private sector, to commercialize the production and marketing of inoculants.

- Information provided by the Group Leader -