The Effect of High Tunnel Production on Pre- and Postharvest Losses of Fresh Produce

The production of fresh vegetables in high tunnels has increased rapidly in the United States due to expansion of organic and local markets. However, little is known about the effect of this system on the pre- and postharvest losses of fresh produce.  The aim of this work was to determine how high tunnel production affects the pre- and postharvest losses by using tomato and spinach as model crops. In 2014, a study was performed at the Kansas State University Olathe Horticulture Research and Extension Center. We utilized a randomized complete block design with six replications and typical production practices for the area were used. Two tomato types (hybrid red ‘BHN 589’ and heirloom ‘Cherokee Purple’) were grown. Samples were harvested at the pink maturity stage based on the USDA color/maturity classification map. Fruit that were free from defects were stored at 12.5^οC and 25^οC for 21 days. Fruit respiration rate was measured every 24 hours during storage. Additionally, color (CIE L*a*b* index) texture, as well as incidence and severity of decay were evaluated daily. The main effect of high tunnel vs. open-field production of heirloom and hybrid tomatoes showed that a 65.6% increase (P<0.001) in total yield (lb/plant), and a 91.0% increase (P<0.0001) in marketable yield of fruit (lb/plant). The average marketability of tomatoes grown in the high tunnel was 84.8%, which was a 15.8% increase over the open-field and was statistically significant (P<0.001). During fall 2014, ‘Corvair’ spinach was planted using the same experimental design. Leaves were harvested at the mature stage. Spinach samples were stored at 3^oC and 13^oC and evaluated using similar methods as listed above for tomatoes. Using high tunnels for organic production could reduce food losses by protecting the crop during production in addition to extending postharvest shelf life. Further experiments will be conducted in 2015 to determine if this trend is consistent across multiple growing seasons.