2019 ASHS Annual Conference

In areas where irrigation is needed and water sources are scarce, several studies have assessed the benefits of irrigation or regulated deficit irrigation on peach plant growth, and fruit production and quality. In Georgia, irrigation is not installed and utilized until peach plants are commercially productive (3^rdor 4^thyear after planting). Until then, plants rely only on rain as their water source. Little research has been done in the past to assess the effects of irrigation on young peach plants in the southeastern US. Additionally, the fertilization rates utilized by the growers were developed decades ago and might need an update in order to keep the production system economically and sustainably viable. The objective of this research was to assess the effects of two irrigation rates (irrigated vs. non-irrigated), two irrigation methods (drip vs. micro-sprinkler irrigation), and four fertilization rates (25%, 50%, 100%, and 200% of the current fertilizer rate) on fruit yield, weight, size, and quality of young peach plants. An orchard of ‘Julyprince’ cultivar grafted onto ‘Guardian™’ rootstock was planted in 2015 (358 plants/hectare) and was utilized for this research. Fruit yield and quality parameters were evaluated in 2017 and 2018 (1^stand 2^ndharvest seasons). In 2017, fertilizer treatments or irrigation systems did not affect fruit yield; however, irrigated plants had 20% greater yield than non-irrigated plants. Non-irrigated plants displayed a slightly-advanced maturation stage (lower chlorophyll content of the fruit - DA index^®) than irrigated plants; and micro-sprinkler irrigated plants had 7% greater total soluble solids (TSS) than drip irrigated plants. No differences were found for fruit weight, fruit diameter, total titratable acidity (TTA), and TSS/TTA ratio. In 2018, no differences in fruit yield were found among fertilizer rates or between irrigation rates; however, sprinkler irrigated plants had a ~90% increase in yield, likely due to an advective freeze that negatively affected the drip-irrigated plants during budbreak. No differences were found for fruit diameter, DA index, and TSS/TTA ratio. Micro-sprinkler irrigated plants had fruits with ~9% greater weight than the drip irrigated plants, and non-irrigated plants had ~5% greater TSS and TTA than irrigated plants. In conclusion, irrigated plants have the potential to have a greater yield than non-irrigated plants especially when succeeding a period of drought. Fertilizer rates can be reduced without negative effects on fruit production. The treatments tested had minor to no effects on the fruit quality parameters.