Plant Performance, and Seasonal Soil and Foliar Nutrient Variations in an Organic Apple Orchard under Four Ground Cover Management Systems

Abstract

A mature apple ( Malus× domesticaBorkh.) orchard was converted to an organically managed system to evaluate the effects of four ground cover management systems (GMS) on soil and foliar nutrient status after 3, 5, and 6 years (2002, 2004, and 2005, respectively) across three cultivars. GMS treatments were applied annually during years 1-6 as follows: wood chips (WC); shredded paper (SP); mown vegetation (Mow); and black fabric cloth (BFC) to mature trees of ‘Braeburn’, ‘Gala’, and ‘Jonagold’ growing on M.9 rootstocks. SP plots had greater soil moisture content in year 4 and a faster water infiltration rate in mid-summer of year 6 compared with the WC, Mow, and BFC plots. WC plots had greater organic matter, [NO ₃ ^-], [Mg], and [B] in soil compared with the other GMS plots. A higher foliar [Mn] was observed on the Mow and BFC plots where soil pH was lower than 6.0 in year 6. Generally, all GMS trees had decreasing foliar [N], [P], and [K] and had increasing [Ca] and [Mg] from April to September in year 6; these concentrations were similar to seasonal foliar nutrient patterns reported for conventional orchards. GMS mulches did not affect tree growth and yield, but cultivars did respond differently.