The effect of fertilization and irrigation treatments on cold hardiness of young peach plants

J. Liu, B. Casamali, M.W. van Iersel, O. Lindstrom, D.J. Chavez
Nitrogen fertilizer has been shown to be positively correlated with cold hardiness of peach trees in some studies. Yet in other studies, nitrogen fertilization impaired cold resistance of peach trees. Supplementary irrigation treatments have also been demonstrated to improve peach cold hardiness and winter survival. The objective of this project was to measure the cold hardiness of young peach plants grown under different irrigation and fertilization regimes to develop guidelines for peach growers to minimize spring freeze damage. Four fertilizer levels (12, 25, 49, and 98 kg ha‑1 N) were tested on both irrigated and non-irrigated two-year old ‘Julyprince’ trees grafted onto ‘Guardian™’ rootstock grown at the University of Georgia peach orchard in Griffin, Georgia, USA. A split plot randomized complete block design was used in this study, with plots being two irrigation systems: sprinkler and drip. For irrigated plants, soil moisture levels were maintained above thresholds that varied from 0.30 m3 m‑3 (May 2016) to 0.15 m3 m‑3 (September 2016). Floral bud cold hardiness was tested three times throughout the winter and critical bud freezing temperatures that caused damage to 50% of samples (LT50) were calculated. Nitrogen fertilizer treatment had no effect on floral bud’s cold hardiness on any of the test dates. Irrigation slightly increased cold hardiness before acclimation (Nov. 7, 2016) by less than 1°C, with the LT50 of irrigated plants being -17.4°C and LT50 of non-irrigated plants being -16.6°C. Overall, irrigation did not affect cold hardiness after bud acclimation (Feb. 2, 2017) and after deacclimation (Mar. 8, 2017). This study showed neither nitrogen fertilizer nor irrigation application had major influence on floral cold hardiness in young peach trees. Instead, other factors, such as yield, fruit quality, and tree health should be considered to optimize fertilization and irrigation management for peach growers in the southeastern USA.
Liu, J., Casamali, B., van Iersel, M.W., Lindstrom, O. and Chavez, D.J. (2021). The effect of fertilization and irrigation treatments on cold hardiness of young peach plants. Acta Hortic. 1304, 215-220
DOI: 10.17660/ActaHortic.2021.1304.30
freezing tolerance, nitrogen fertilizers, flower buds, LT50, hardiness, Prunus persica, irrigation scheduling

Acta Horticulturae