Comparison of organic eggplant yields under open-field and high tunnel production systems in Texas

High tunnel (HT) vegetable cultivation stands out as a superior choice when compared to open field (OF) production due to its numerous production benefits. However, intensive cultivation practices involving excessive use of inorganic fertilizer (IF) in HT production systems may lead to degradation of soil health, and ultimately poor crop yields. Therefore, this study investigated the effect of liquid organic fertilizer (LOF) and IF on growth and yield of eggplant (Solanum melongena L.) cultivars in HT and OF production systems. Two experiments were conducted in a split-split plot design with production systems (HT and OF) as main plot, fertilizers (LOF and IF) as sub-plot, and cultivars (‘Angela’ and ‘Jaylo’) as sub-sub plot factors. Throughout the growing season, daily average temperature and relative humidity were greater by 2 to 4 ​°C and 2 to 4%, respectively, under HT compared to OF conditions. In contrast, average daily light integral of HT decreased 18 to 24% compared to OF. Results from pooled growth and yield data of both experiments indicate HT produced 61% taller plants with 62% thicker stem diameter compared to OF. However, eggplant height and stem diameter did not differ significantly between fertilizer treatments or between cultivars. Due to a greater fruit count for each plant (63%) and average fruit weight (9%), total yield was 84% greater in HT compared to OF. Eggplant cultivar ‘Jaylo’ yielded 33% greater fruit count for each plant and 38% greater fruit yield compared to ‘Angela’ cultivar. However, no differences in fruit count, fruit weight, and the total yield were observed between LOF and IF. Results indicate that HT production offered a favorable microclimate which encouraged plant growth and greater fruit yield of eggplant compared to OF conditions. LOF and ‘Jaylo’ could be successfully used in organic eggplant production in HT and OF systems.