“…Water shortages greatly limit apple growth in the hill and gully region within the Loess Plateau (Zhang et al, 2017), but there are limited data on the impact of low soil moisture on fruit quality and yield during the blooming and fruit-expansion stages of apple trees (Zydlik et al, 2004;Leib et al, 2006;Nemeskéri, 2007;Naor et al, 2008;Talluto et al, 2008). Artificial irrigation is an effective way to improve water supply within this region, and many water-conserving methods have been proposed, including surface drip irrigation (Parvizi et al, 2014;Neilsen et al, 2015), deficit border irrigation (Bianco and Francaviglia, 2012;Faci et al, 2014), alternate partial root-zone irrigation (Zegbe and Serna-Peréz, 2012;Villagrán Deoses et al, 2015) and subsurface drip irrigation (Zhao et al, 2014;Chenafi et al, 2016). Surface drip irrigation (SDI) has proven to be more effective than traditional irrigation methods (Raina et al, 2013).…”