Bag or bulk? A decision-making checklist (NRI Bulletin No. 45)

This bulletin is prepared as a guide for policy makers and administrators considering economic and technical improvements to national food-grain storage and distribution. Bulk storage and handling are widely thought to be effective ways to reduce operating costs, including losses, although there are many other reasons for considering change. The text first identifies questions leading to a decision on the feasibility of bulk handling under local conditions. The second part of the text looks for the potential economic and technical advantages of bulk handling over other systems, including upgrading of existing systems

A rapid method for loss assessment in stored maize and dried cassava. Interim report for project R5103

This paper describes a new method for the rapid assessment of losses in stored maize cobs and dried cassava chips (cossettes): the use of visual damage scales. The scales can be calibrated against conventional weight loss assessment techniques to permit the estimation of percentage weight losses in stores. The scales were first developed for a survey of Larger Grain Borer beetle (Prostephanus truncatus (Horn)) damage in farm stores in central Togo. They were constructed by sorting infested maize and cassava by eye into different damage classes(four classes for maize cobs and five for cassava chips). In the survey, each sampled cob or chip was scored for damage on the appropriate visual scale, using reference photos to ensure consistency. Advantages of the method include: it is quick and easy to use, increasing the number of stores which can be sampled; data loss or fabrication is reduced; anomalous results can be checked on the spot; and it increases farmer participation in the survey work. Methods of data analysis are discussed in detail. The raw (ranked) data can be analysed by chi-square tests, rank correlation and ordinal logistic regression. Alternatively, if the scales are used to estimate weight losses, this permits the use of more powerful techniques such as analysis of variance. The scales have potential for many types of survey work, especially rapid appraisal. one of the most interesting applications could be to estimate parameters such as loss in market value and loss of final food product (rather than whole grain), but more work is needed to devise appropriate ways of calibrating the scales for this purpose

Rapid assessment methods for stored maize cobs: weight losses due to insect pests

This paper describes a new method for the assessment of weight loss due to insect pests in stored maize cobs. The method involves scoring each cob in the sample on a visual damage scale and then using a simple equation to estimate overall sample weight loss. The coefficients in the equation are determined in advance of field work by calibrating the visual scale against a laboratory loss assessment technique. The visual scale method was found to be rapid, simple and had many advantages for on-farm work. Precision of the results was shown to be similar to that of existing weight loss assessment methods

Small farm weed control An annotated bibliography

SIGLELD:83/00725(Small) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Reducing losses in small farm grain storage in the tropics

Over two-thirds of all grain produced in the tropics is stored at farm level. Most traditional storage systems are well adapted to their environment and losses are generally low - typically below 5% of grain weight over the storage period.· However, several factors have increased potential losses in farm storage over the past two decades. These include the adoption by small-scale farmers of high-yielding crop varieties which put a strain on existing post-harvest systems, the threat to traditional storage technologies posed by the decreasing availability of important inputs such as construction materials and fuelwood, and, in Africa, the advent of a new storage pest (the larger grain borer). At the same time, recent economic changes in many countries (especially in Africa) have created incentives for farmers to store more grain. This paper critically discusses the main technical approaches to reducing storage losses in the context of the constraints commonly faced by the small-scale farmer. Possible approaches include pre-storage methods (such as timing of harvest), improved drying, better storage structures, appropriate crop varieties, the use of commercial pesticides or locally produced insecticidal materials, and biological pest control. Of these, appropriate varieties (high-yielding and resistant to deterioration in storage) would be the ideal solution, but this is not always feasible. Pesticides are probably the most successful storage technology to date: they are easy to incorporate into most types of storage systems and when correctly used can give high returns to the farmer's investment. The main problems are ensuring an adequate supply of suitable, well-packaged pesticides and in educating farmers to choose and use them correctly and safely. The most difficult technologies to promote to the small farmer are new storage structures and grain dryers, due to their high capital cost; however, small silos have been very successful in some wealthier areas. It is concluded that, although substantial research and development efforts have gone into this area, there have been many cases where 'improved' storage technologies have not been taken up by small-scale farmers. M any of these technologies turn out to be inappropriate for farmer needs, or are not available at the right price and the right time. It is recommended that governments and other organizations wishing to help reduce storage losses work closely with farmers (including women) to design more appropriate technologies, and to help overcome constraints such as poor input supply and lack of finance. Suggestions are made for future research

Involving grain traders in determining the effect of post-harvest insect damage on the price of maize in African markets

Quantifying the loss in value of maize associated with insect damage can be difficult where commodities are sold using non-standard measures and where price is determined through bargaining, as in most African markets. This paper describes a methodology developed in Ghana in which panels of experienced maize traders priced prepared maize samples showing different levels of insect damage. The relative price of damaged maize was quite consistent across the markets studied. Of the grain characteristics evaluated, percent damaged and mould-discoloured grains was the most practical and reliable predictor of price. At harvest a 1% increase in damaged grains decreased price on average by 1%, but later more damage was tolerated as maize became more scarce