Back in 2012, Cravo teamed up with Dr. Greg Lang from Michigan State University to help develop strategies for improving the profitability of sweet cherry production using automatic retractable roof houses. The results from these early trials at Michigan State University led to commercial installations on four continents. In this article, Cravo shares a list of key results achieved so far after eight years of growing cherries under automatic retractable orchard covering systems.
- Yield has been increased from 7 to 17 tons per hectare under a retractable roof compared to netted orchards.
- Harvest can be advanced by 2-3 weeks.
- Pollination problems have been reduced.
- Fruit size is larger without a reduction in firmness.
- Fruit ripening and sizing is more uniform helping to reduce picking cost.
- 1st grade pack out percentage has been increased to 95% +.
- Catastrophic loss from frost, rain, strong winds, hail, and extreme heat has been prevented.
- Full harvest has been achieved 1 year earlier.
- Up to 50% reduction in water usage during the summer after the harvest.
These results have been achieved by employing seven strategies using the automatic retractable orchard covering systems by:
1. Advance bud break by 2-3 weeks
2. Optimize pollination & fruit set by creating optimal temperature and humidity levels and protecting from strong winds
3. Prevent losses from fruit abortion by preventing imbalances between soil/ root temperatures (water supply) and transpiration (water loss).
4. Prevent smaller soft fruit when trees are exposed to hot dry conditions during harvest (Close the roof covering to reduce transpiration rates and lower fruit temperatures).
5. Maximizing tree recovery and carbohydrate accumulation post-harvest by closing the roof 85% on hot sunny days.
- Automatically increase carbohydrate accumulation and reserves for the following season crop by optimizing both transpiration and photosynthetic rates.
- Prevent damage to leaves, spurs, trunk and roots by using the roof covering to block excessive radiation to prevent excessive plant temperatures, transpiration and water stress.
- Reduce water usage by up to 50% by preventing transpiration.
6. Increase chill accumulation hours using the roof covering to decrease tree temperatures by block direct sunlight on sunny days.
Temperatures measured in Tasmania, Australia on August 22, 2018. The tree temperature is 20.5ºC (68.9ºF) under direct sun and is 7.8ºC (46ºF) when the Cravo roof blocks the direct sun.
On September 4, 2018 in Curico Chile, the air temperature was 23ºC (73.4ºF) but the part of the tree trunk exposed to the direct sunlight was 38ºC (100ºF). This dramatic increase in tree temperature can cause a reduction in the total number of chill hours.
7. Prevent catastrophic loss