The following example demonstrates the use of Loss reducer for assessing the impact of investments into loss reduction measures. The example focuses on the harvesting link of the postharvest chain and explores the possible promotion of two new 'technologies' that might reduce losses at harvest time. Most of the figures used in this example are fictitious.

If there is damp weather at harvest time and no loss reduction measures are being used then the grain may rot in the fields. As a result grain weight losses may then be 16.3% (as shown in the image below).

Screen shot 4

No investment in reducing harvesting losses due to damp weather at harvest time

In this scenario, if all losses in the postharvest chain are taken into account then only 70.23% of the original mature crop remains (see the green bars below, which are normally in the top right hand panel of Loss reducer).

App 5

The amounts of crop remaining in each link of postharvest chain as a consequence of losses

It is understandable that someone may wish to reduce these losses. For example, there could be a campaign to ensure cobs are turned downward on the plant to prevent water entering them (see the cartoon below). This keeps them dry and reduces the losses at this link in the postharvest chain.

App 6

Mature cobs on the maize plant can be turned downwards in rainy weather to prevent water accumulating in them.  This reduces postharvest losses.

To examine the likely dynamics of such a campaign the sliders of the app need to be reset to reflect the changes it could make.  The values are predetermined and are to be set as follows:

App 6a

Screen shot 5 b

 Investment made in reducing harvesting losses by supporting a 'turn cobs down' campaign

In this scenario, losses at harvest can be reduced from 16.3% down to 12.59% (a loss reduction of 3.71%). Taking into account all losses in the postharvest chain then 73.34% of the original mature crop will remain (3.11% loss reduction).

Loss reduction app Fig 4

By supporting a ‘turn down' campaign 73.34% of the crop remains at the end of the postharvest chain, previously only 70.23% remained

The difference between the loss reduction achieved at the harvesting link, 3.71%, and the reduction in loss of the entire mature crop after passing though all links 3.11% (73.34%-70.23%), results from greater quantities of grain flowing through the other links so that these now have greater absolute losses.

The loss reduction campaign so far has been based on changing behaviour so that maize cobs are turned down. In this scenario we know that at best a loss reduction of only 65% is possible. However, a complementary new technology, such as the use of plastic sheets at harvest time (see cartoon below), could be introduced simultaneously to increase the amount of loss reduction. The sheets would prevent the harvested cobs from contact with damp ground and in the event of rainfall can be folded over to keep the cobs dry. The sheets could be distributed with a degree of cost subsidy to lower any perceived financial risks to adoption. Used together the 'turn cobs down' and 'plastic sheet' technologies could prevent 80% of losses.

App 8

Using a plastic sheet at harvest time can reduce losses by prevent contact between cobs and damp ground.  Sheets can also be folded over to protect cobs during rain showers.   

Improved loss reduction is not the only benefit, farmers find the sheets very useful and are incentivised by the subsidy, so the inclusion of subsidised sheets raises the profile of the promotion campaign making successful adoption easier to achieve. Consequently, there is a lower tipping point for self-perpetuating adoption and the upper threshold can be reduced from 80 down to 60. However, the increased costs of the campaign mean that the available resources will now only reach 65% of target households.

The sliders are reset to reflect these changes, as shown below.

Screen shot 6

Investment made in reducing harvesting losses by supporting a turn cobs down campaign and supply of subsidised plastic sheets

In this scenario, despite only being able to a reach a lower proportion of target households (65% instead of 70%), losses can be reduced from 16.30% down to 7.82%, a reduction of harvesting losses of 8.48% and an overall loss reduction of the crop after all links in the posthavest chain of 7.11% (77.34% – 70.23%).

Loss reduction app fig 6

By supporting a ‘plastic sheet and turn down cob’ campaign 77.34% of the crop remains at the end of the postharvest chain, previously with only ‘turn down cob’ 73.34% remained

This may or may not be a good return on investment.  To check this, it must be established that the value of grain saved over time exceeds the campaign costs. The farmers will also make their own estimate of potential benefit prior to adoption.  This is likely to include estimation of personal risk, opportunity cost and cultural issues. The benefits of increasing the project investment, to support greater adoption, can be explored by pushing the 'Investment' slider to the right.

This is an example of interventions at only one link in the postharvest chain. The app allows you to make interventions simultaneously anywhere else in the other seven links of the chain and observe their combined effects on loss reduction.