Measuring food production waste -blackcurrants

The full report is in the Reports section of the field lab page, but below is a list of the key findings:

• The results indicate a surprising level of losses, over 4x the expectation of most growers we spoke to. The level of losses ranged from 22-39% of the total weight of blackcurrants produced (growers' original estimates prior to data collection were 5-8% losses).
• Nearly all losses occurred at the point of harvest rather than prior to harvest
• Few berries were lost due to sun scorch, botrytis or early ripening and premature dropping. There were also very few unripe berries - less than a few grams per sample
• Losses did not appear to be significantly higher at the end of rows
• Average losses increased significantly at one farm when including a sample point where almost no berries were harvested, because bushes were not sufficiently shaped/pruned, therefore were pushed rather than caught by the machinery. This demonstrates the importance of pruning to maximise yields, though over-pruning may reduce photosynthetic opportunities, potentially impacting yields in the following year.
• There were no unharvested fields at the end of the season at any of the four farms. In other years or varieties, surplus or losses may be higher or lower due to weather and the characteristics of different varieties (e.g. resilience to wind exposure, winter chill requirements)

In a final workshop to go through the results, the growers discussed variables that may have caused the difference in losses between farms, such as forward speed of the harvester, shaker speed, type of machinery. They are keen to conduct further research in the next harvest season to compare set ups and machinery to determine optimal set up. If the research goes ahead, it will likely take place at one farm to reduce the number of variables between farms.

Four farms were visited by the researcher and coordinator to collect data during the Ben Klibreck harvest in the last week of July. All farms are situated along the east coast of England from Kent to Norfolk. The methodology below was followed and the data will now be analysed and written up into a final report which will be available in the Documents section at the top of this page.

At one farm, one 15 metre strip of sheeting was laid down instead of five 3 metre strips, meaning there was one longer sample point. However, farm staff were able weigh the exact amount harvested along that strip, meaning that the results for that farm will be very accurate for that strip.

For the other growers, data on the berries collected pre- and post-harvest will be compared with average yields for that field.

From a group workshop and further discussions facilitated by the coordinator (Innovative Farmers), researcher (3Keel) with input from the farmers and Ribena agronomist, the group developed a methodology to assess the quantities of waste in their production system. On analysis of that waste data, the group will meet to discuss how they could approach mitigating and reducing waste.

Methodology:

1) Growers to choose five samples points of 3 metres long each, including one end of row. The bushes should be mature and representative of average bushes in the field, without gaps between bushes
2) 4-7 days before harvest: Growers to pin down sheeting at sample points to collect blackcurrants dropping prematurely. Estimate % underripe
3) Day of harvest: Collect blackcurrants that collected on the sheeting, weigh these and discard
4) After harvester has gone over the row, collect all berries that dropped on the sheeting and weigh these. Estimate % underripe and % overripe. Repeat this with any blackcurrants that remain on the bush
5) Yield data to be provided to researchers, as well as data on any area which remained unharvested at the end of the season

The group of blackcurrant producers will be looking at the issue of food waste in primary production, in one of the four sector-based field labs sponsored by WRAP.

The coordinator conducted initial phone interviews with interested growers to understand their experiences, challenges and successes in managing on-farm losses/surplus, and what they felt were the key waste hotspots (i.e. pre or post harvest) and the drivers of this. Key waste drivers were identified, which include:

• Uneven ripening of blackcurrants due to lower levels of winter chill in recent years
• Overproduction due to yield uncertainty and the need to meet contracted tonnage
• Lack of frozen storage facilities at most farms
• Harvesting machinery and harvesting speed settings
• Bush shape, with neat v-shape preferable to a sprawling, wide bush

The growers most interested in taking part in data collection were identified through contact with the agronomist at LR Sunsory, producers of Ribena.