|MERCHAN-PANIAGUA, SARA - UNIVERSITY OF MISSOURI
|MOTAVALLI, PETER - UNIVERSITY OF MISSOURI
|ANDERSON, STEPHEN - UNIVERSITY OF MISSOURI
|NELSON, KELLY - UNIVERSITY OF MISSOURI
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/9/2005
Publication Date: 9/27/2005
Citation: Merchan-Paniagua, S., Motavalli, P., Anderson, S., Nelson, K., Sadler, E.J. 2005. Slow-release N fertilizer to control nitrogen losses due to spatial and climatic differences in soil moisture conditions and drainage [abstract] [CDROM]. ASA-CSSA-SSSA Annual Meeting Abstracts.
Technical Abstract: Agricultural soils are a major source of nitrous oxide (N2O) which contributes to global warming and ozone depletion. The objective of this research was to establish the relationship between soil N2O flux, temperature, soil NO3O--N, and soil water content and to compare the performance and cost-effectiveness of polymer-coated urea and conventional N fertilizers in relation to soil gaseous N losses. A two-year field trial planted to corn was started in 2004 at the University of Missouri Ross Jones Farm in Northeast Missouri on a claypan soil. Treatments consisted of 46 m long plots with: i) no drainage or subirrigation, ii) drainage with tile drains spaced 6 m apart and no subirrigation, iii) drainage with tile drains spaced 6 m apart and subirrigation, and iv) no drainage and overhead irrigation. The plots were split into N fertilizer treatments of broadcast pre-plant-applied urea or polymer-coated urea at rates of 0, 140, and 280 kg N ha-1. For each treatment combination there were 4 replications. The results show that in the relatively high rainfall year of 2004, corn grain yield increased in the polymer-coated urea- treated plots with no drainage or irrigation. Nitrate-N was generally higher in the urea-treated plots at the beginning of the season but was lower later in the season. In comparison, soil N2O loss was affected by changes in soil temperature and water content due to rainfall and the different drainage and irrigation treatments. The measured soil N2O flux was highly variable, but polymer-coated urea reduced N2O flux in plots with no drainage and overhead irrigation. The results of this research suggest that polymer-coated urea may reduce soil N loss compared to conventional urea under relatively wet conditions, but additional evaluation must be conducted to determine whether this N fertilizer source is cost-effective for agronomic crops.