Irrigation and Fertilization of Peach Trees in the Southeastern US

In the southeast United States, young peach trees are not irrigated until their first two or three years after planting. Trees rely only on natural precipitation as their water source. Dr. Chavez identified this as an important area of research as orchard establishment and care can affect fruit production and orchard longevity. The current recommendations for irrigation and fertilization used in Georgia are believed to be based on studies performed in California under environmental conditions not representative of Georgia’s environment.

Dr. Chavez in collaboration with Dr. Van Iersel co-advised Dr. Bruno Casamali during his doctoral work. Dr. Chavez established a field experiment at the Dempsey Farm with a total of 240 plants of ‘Julyprince’ peach variety planted in July-August 2015. The variety was divided in a split plot randomized complete block design, with two main plots: sprinkler and drip irrigation. Treatments are different fertilization and irrigation levels combinations. Four fertilization levels: 12.5, 25, 50, and 100 kg of N per hectare for one-year-old plants, and 17.5, 35, 70, and 140 kg of N per hectare for two-year-old plants; and two irrigation levels: no irrigation and optimum irrigation [volumetric water content of 15-25% (20% from April to May, 25% from May to August, 20% from August to September, and 15% from September to October)]. Data was collected in 2016, 2017, and 2018. It is important to mention that 2016 was a year of extreme drought in which plants without irrigation showed symptoms of stress. In addition, irrigated vs. non-irrigated trees visually presented extreme differences in growth and tree architecture. Other variables are currently being analyzed to determine trends and relationships established between drought and the peach tree physiology. Dr. Chavez is continuing this study to establish tools to be used by the peach growers for irrigation management.

Dr. Chavez continue with the irrigation and fertilization studies in the field with Mrs. Srijana Thapa Magar, a PhD candidate. She has collected data for 2019 . This year, the field plot will reach its fifth leaf with a fruit production potential for each tree. Fruit quality analyses will be performed for the different treatments.

In addition, Dr. Chavez in collaboration with Drs. Vellidis and Liakos, have developed a SmartIrrigation Peach app. This app is currently being tested in the plot established in 2015 as a mature orchard and in a new plot established in 2020 as a new orchard.