Biological Nitrogen Fixation College of Tropical Agriculture and Human Resources (CTAHR) Biological Nitrogen Fixation UH Seal Unversity of Hawaii at Manoa
Project History
Training Resources
Inoculant Technology
Project Impact

Inoculant Technology

Production & Quality Control

Inoculation of legume crops is a cost effective technology in developed and developing countries
However, inoculant products are not widely available in most developing countries. Technical and logistical constraints prevent U.S. manufacturers from exporting to established developing country markets. The direct transfer of U.S. production technology to developing countries is, however, also not always feasible since the scale and materials used in U.S. systems are seldom suitable for prospective producers in developing countries. Fledgling production facilities, developed with donor support in national institutes, exist in many developing countries; but they have failed to exploit the potential of local markets. Inoculant supply in local markets is limited by production costs and demand is constrained by poor product quality.

Constraints to increasing BNF by legumes include: 1) poor inoculant quality assurance; 2) unacceptable inoculant formulations and performance; 3) technical limitations to commercial inoculant production and marketing.  NifTAL address these constraints with three research and development strategies by: 1) modifying existing technologies in the short term and; 2) developing new products for inoculant industries in the long term; 3) designing technologies and products with the assistance of the end-users m industry and research institutes.

Inoculant formulations limit commercialization and field performance. Our goals are to simplify inoculant marketing, reduce costs, improve performance and expand markets for inoculant products through improved inoculant formulations.

In the production of inoculants, rhizobia are mass cultured in fermentor vessels and the culture is then used to impregnate a sterile or non-sterile inoculant carrier. Standard formulations use humus (peat) as a carrier, but expansion of inoculant markets based on humus carriers in both developed and developing countries is limited.

As the scale of farm operations increases, US farmers are demanding inoculants that are more convenient to apply than peat-based inoculant. Liquid formulations are becoming the product of choice since they are more easily adapted to large scale seeding operations.

In developing countries, use of humus carriers is limited by cost and availability. For example, NifTAL developed business plans created for MAHYCO Ltd. (Bombay), Kenya Seed Co., and other firms indicate that humus and its processing will account for 50-75% of production costs. Most developing countries in the tropics have inadequate deposits of quality humus. The Indian industry is forced to use inferior alternative carriers such compost, lignite, and charcoal. The poor carriers contribute to that country's problems with product quality. Thailand's humus deposits have been mined intensively for 12 years and are nearly exhausted. Within a few years the Thai industry may import, at greater cost, Canadian peat to meet their demand.

Liquid inoculant products will solve many of these problems. The liquid formulation is becoming increasingly popular with farmers throughout the developing and developed world.  In terms of convenience, farmers would ultimately prefer inoculant marketed as a pre-coating on seed.  Both liquid and pre-coated inoculants will require further improvements to become equivalent to peat-based carrier for overall survival of the rhizobia under adverse conditions.  Inoculant formulations allowing seed companies to pre-coat legume seed could greatly expand the market for legume inoculant in the US and abroad.

Appropriate inoculant production systems can exploit small markets in developing countries. Although inoculant production can be made fairly scale-neutral, cost-effective systems with low throughput volumes have not been specified. The startup costs and difficulty developing inoculant markets among small farmers in developing countries require that firms recover their investment and operate profitably at low volumes. NifTAL's earlier conceptual design of a Micro-Production Unit (MPU) addresses this issue and has received favorable reviews from several producers. Precise design and specifications, protocols and materials now need to be formalized, tested and made available to prospective producers.

Poor inoculant quality limits market development. Nearly 50% of inoculants from developing countries tested by NifTAL were of unacceptable quality and would not have benefited farmers. A recent UNFAO consultant's report on Indian inoculant quality concluded fewer than 10% of the inoculant marketed was of useable quality (Thompson, 1992). According to this report, the Indian legume inoculant market has failed to develop, primarily because of lack of farmer confidence. In most cases there was inadequate quality control in the production process, and product quality was not monitored in the distribution chain.

Part of the quality-assurance problem can be addressed by training; however, there is a need in both developed and developing countries for improved quality-assurance methods. Quality-assurance methods must be more rapid, precise, and convenient if producers and external quality control agencies are to rigorously monitor inoculant quality from production to application in the field. An example of the technical inadequacies of an existing standard method is the plant infection method (MPN). This method is labor intensive, requires three weeks, and is precise to within only one log (order of magnitude) of the actual count. This method cannot help the industry as a tool make production decisions. Existing quality assurance methods also create inefficiencies in some markets by delaying product distribution until lengthy assays can be completed by regulatory authorities.

To address constraints to improving BNF in developing countries, NifTAL has developed key resources documents on inoculant production and quality control, which are available below.

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