602 Influence of Tillage and N Source on Gas Exchange in Tomato

Abstract

The purpose of this study was to evaluate the tillage method effects of N sources on gas exchange (GE) at the flowering, fruiting, and pre-senescence in tomato. Measurements of transpiration (E), stomatal conductance (gs), photosynthesis (Pn), and internal leaf CO2 concentration (Ci) were reported. The following fall/spring tillage and fertility treatments were applied: 1) fall-fallow/spring-moldboard, 2) fall-fallow/spring-moldboard + 90 kg·ha–1 N, 3) fall-moldboard + hairy vetch/spring-chisel, 4) fall-moldboard + hairy vetch/springchisel + 90 kg·ha–1 N, 5) fall-minimum till+hairy vetch/spring-chisel, and 6) fall-minimum till + hairy vetch/spring-chisel + 90 kg·ha–1 N. During the 2nd week of Apr. 1995, `Mountain Pride' tomato was transplanted in all plots. Maximum E (11.9 mmol·m–2·s–1), gs (1465.1 mmol·m–2·s–1), and Pn (22.23 μmolCO2/m2 per s) occurred at the fruiting and highest Ci (301.2 μL·L–1) at the flowering. Throughout the growing seaon, treatments 5 and 3 affected GE rates the most, while treatments 1 and 3 at flowering affected Ci the most. Results indicate that fall moldboard or minimum-till + hairy vetch/spring chisel had greatest influence on GE of tomato.