298 Root Restriction and Fertilizer Effects on Young Peach Trees

Abstract

Shoot growth of peach trees can be managed by manipulating edaphic conditions such as root volume and soil fertility. In this experiment, 2-year-old peach trees (Prunus persica L. cv. Sentry on `Lovell' rootstock) were planted in pots with a split root design, so that half the roots were not treated and the other half received one of four treatments: root volume restricted with polypropylene nonwoven fabric (FAB), fertilizer alone (FER), FAB + FER, and untreated control (UTC). Total shoot growth and root growth were measured, and root growth in the split halves was compared. FER increased leaf number and weight by 48% and 60%, respectively, but not stem growth. Leaf nitrogen concentration and photosynthesis were greatest in FER treatment. FAB did not affect shoot weight or reduce total root weight or length, although roots did not grow past the fabric barrier. FER increased root weight and length (116% and 57%, respectively, compared to UTC) on the treated half but did not affect root growth on the untreated half. Greatest root growth occurred in the root half that received FAB + FER, particularly in the 5-cm soil segment proximal to the fabric (4.6 cm•cm-3 compared to 0.8 cm.cm-3 in UTC). Shoot length was greater in FAB + FER than FAB. Thus, fertilizer applied near fabric increased root growth and the combination of fertilizer and fabric may be used to regulate shoot growth. Specific root length (root length per gram dry weight) was highest in trees with no treatment, suggesting root acclimation to low nutrient soil conditions. Lower specific root length resulted in soils that were fertilized. The results indicate that nonwoven fabric restricts root growth in peach trees and reduces shoot elongation. The combined effect of fabric plus selected application of fertilizer may be used to regulate growth of peach trees.