Management of water and nutrient through fertigation and the impact of rootstock to optimize yield and maximize quality in apples

Abstract

Water usage, tree growth, leaf mineral nutrients, yield, and fruit quality attributes in ‘Autumn Rose Fuji’ apple (Malus × domestica Borkh) under five irrigation systems (full sprinkler (FS), 50% full sprinkler (50% FS), full drip (FD), 65% full drip (65% FD), and 50% full drip (50% FD)) between 2008 and 2011 and effects of four rootstocks (Bud 9, RN 29, Supporter 4, and G30) and two irrigation systems (FS and FD) on tree trunk cross sectional area (TCSA) in 2006, cumulative yield in 2006 and 2007, fruit quality between 2004 and 2007, and leaf size and leaf mineral nutrient between 2002 and 2007 in ‘Pacific Gala’ were studied. On average, each tree with an FS system received 5927 L and each tree with FD received 3609 L water per season. ‘Autumn Rose Fuji’ trees receiving FS and FD had higher yield tree-1 and larger fruit than those with other treatments. ‘Autumn Rose Fuji’ trees with 65% FD and 50% FD received much lower volumes of water while they had significantly larger fruit compared to the trees with 50% FS. ‘Autumn Rose Fuji’ fruit soluble solids concentrations (SSC) increased in all trees that received any water-deficit treatment, leading to a significantly higher SSC in trees with 50% FS. In ‘Autumn Rose Fuji’, concentrations of leaf N, Ca, and Mn were higher than those in any drip irrigation, and leaves from trees with FS and FD treatments had higher K. ‘Pacific Gala’ trees on Bud 9 rootstock were smaller and had higher leaf N (as expressed on mg cm-2 of leaf area), Ca, Zn, and Mn, but lower K than those on other rootstocks. Bud 9 and G30 rootstocks enhanced the fruit maturity of ‘Pacific Gala’ by increasing fruit SSC and reducing fruit firmness. In ‘Pacific Gala’, drip irrigation increased fruit size and advanced fruit maturity by increasing SDP and reducing firmness as compared to sprinklers system. Overall, drip systems are recommended for both ‘Autumn Rose Fuji’ and ‘Pacific Gala’ production.