Evaluating Fertilizer Application Strategy for Improving Crop Yields and Reducing Mineral Nitrogen Leaching in High Rainfall Areas of Taiwan

Abstract

A 2-yr pot experiment conducted on an upland sandy clay loam soil in National Taiwan University, Taipei evaluated crop yields and mineral nitrogen (N_min) leaching as affected by fertilizer application strategy, viz., inorganic (100% N from urea), organic (100% N from compost), combined (compost plus urea) and a zero control (Ctrl) treatments. Cabbage (Brassica oleracea L.) and corn (Zea mays L.) were grown in annual rotation under simulated high rainfall conditions. The N_min leaching was monitored adding 83 and 62 mm of water fortnightly to cabbage and corn respectively for a total of 28 times. One-way ANOVA was used to determine the statistical significance of treatment effect and Tukey test for means comparisons (p = 0.05). Treatment differences were subtle for dry matter yields (DMY) but the treatments were strikingly different for 2-yr cumulative N_min leaching (6.66% in organic, 30.6% in inorganic and 8.10% in combined treatments). This difference was largely related to the ability of soil to an increased retention of added N under organic and combined fertilization treatments. Unlike reported elsewhere, N recoveries were relatively high in compost applied soils, with or without urea fertilizer application. It is concluded that framers’ practices of fertilization that has inherent problem of excessive N leaching in high rainfall areas of Taiwan could be improved by proper compost and urea combinations within agronomically recommended rate of N application.

DOI: http://dx.doi.org/10.3126/njst.v12i0.6472

Nepal Journal of Science and Technology 12 (2011) 7-16