Drying systems to improve grain quality in north-east India

• Central Mechanical Engineering Research Institute, India

Effective grain drying is essential in south Asia's monsoon belt. In India's West Bengal region drying of maize and rice is important for short term food security. Seed is used for food and also for feeding animals, a vital source of draught power. Longer term security through ensuring feeds for following crops and for sale to increase income are dependent on maximising harvested seeds in a humid environment were spoilage is common. Static yields and low prices mean that even small reductions of post harvest losses can translate into significant additional security and income. Storage of surplus grains until periods of shortage when prices are higher only provide income if the grain is of sufficient quality. Current grain drying systems are based on technology that is up to 20 years old. This is inefficient, both in terms of dried grain quality and also energy inputs. Exacerbating these problems are losses during storage and transport, mainly from inattention to moisture removal. The resulting losses can be 20 per cent or more of production.

Enhancing the technology used could substantially improve grain industry efficiency and profitability, especially for small holders. A major barrier to enhancing grain drying has been the use of inappropriate systems and technologies. The poor match of these to the agri-ecological conditions, characterised by monsoonal rains and humidity, has been a key failing. The relatively poor levels of local understanding of moisture intake of grains and inability to engage local involvement have furthered this mismatch. As a consequence sun drying, being both labour and land intensive, is still widely used, during harvest and periodically during storage. The risks of spoilage and contamination are high, such as aflatoxin in dried maize to be used as stock feeds. Mechanical drying is a better option, with some small scale adoption already underway. However few smallholders are in a position to adopt this without support, mainly from NGOs.

Local seed processors are well placed to do so and are being supported by the scoping, development and dissemination of better systems for grain drying under the humid topical conditions of south Asia.

The focus will be on seed and feed drying to enhance farmer incomes and on developing modelling and manufacturing expertise. Defining the thermodynamic parameters of the commodities and data on climate will allow the use of models to accurately determine system parameters.

A two stage drying approach will be used, with the first stage drying looking at options for smallholders prior to delivery of grain to cooperatives. Linkages with local partners will be established to adapt previously developed to local conditions, as well as the precise requirements of seed and feed drying. These linkages will then allow collaborative design, construction and trialling of drying systems. Tailored training workshops will disseminate this information. The first stage dryers are yet to be determined, awaiting modelling outputs. Similarly second stage dryers will be selected to match handling systems used in storages.