Growth, Evapotranspiration, and Nitrogen Leaching from Young Lysimeter-Grown Orange Trees

Abstract

Lysimeters constructed from polyethylene tanks were filled with Oldsmar fine sand soil. A single “Midsweet” orange on Carrizo citrange rootstock tree was planted in each lysimeter on May 5, 1991. Fertilization treatments included traditional fertilization using applications of dry-soluble fertilizer at 6-week intervals (TF), weekly fertigation applications (WF), and single annual applications of two different controlled-release materials (CR). Irrigation (by microsprinklers) and drainage volumes (collected weekly) were measured with totalizing flow meters. Trees fertilized with CR products achieved equivalent growth to trees on the TF and WF treatments, even though the CR treatment trees received only 44% of N as the other treatments. The fertigated trees averaged about 14% greater evapotranspiration (ET) during the period of study as compared to the nonfertigated trees. As the trees grew, the average ET increased from 2.8 and