Fertilizer Concentration and Leaching Affect Nitrate-Nitrogen Leaching from Potted Poinsettia

Abstract

The influence of fertilizer concentration and leaching volume on the quantity of applied N and water that were leached from a container-grown poinsettia crop ( Euphorbia pulcherrima Willd.) was investigated. The NO 3 -N quantity leached after 71 days increased with higher NO 3 -N application rates (7, 14, or 28 mol NO 3 -N/m 3 ) and higher leaching volumes; it ranged from 0.03 g NO 3 -N [7 mol·m -3 , 0.00 container capacity leached (CCL)] to 7.65 g NO 3 -N (28 mol·m -3 , 1.0 CCL). The NO 3 -N concentration for saturated media extracts increased with lower leaching volumes and higher fertilizer concentrations. For example, when 7 mol NO 3 -N/m 3 was applied, NO 3 -N in the medium was 27.1 mol NO 3 -N/m 3 when 0 CCL was used, but it was 8.6 mol NO 3 -N/m 3 when 1.0 CCL was used. Shoot height and dry mass were not affected by the treatments. Leaching treatments also did not influenced leaf area, but leaf area was larger at 7 compared to 14 or 28 mol NO 3 -N/m 3 .