Irrigated potato (Solanum tuberosum L.) production requires significant inputs of
fertilizer N for optimal tuber yield and quality. However, high N rates carry the risk of
high N loss, particularly in coarse-textured, well-drained soils where potatoes are
commonly grown. Polymer coated controlled-release ureas (PCU) have shown promise in
- leaching, a groundwater quality concern, and may potentially also reduce
emissions of N2O, a greenhouse gas with nearly 300 times the warming potential of
carbon dioxide. However, comparisons of multiple PCUs are uncommon. Studies were
conducted over three years to compare N loss (as NO3
- and N2O), yield response, and N
use efficiency (NUE) from an unfertilized control, split applied conventional N fertilizer
(CSA), and two PCU products (PCU-1 and PCU-2) applied at 270 kg N ha-1 yr-1. Tuber
yields, NUE, and leaching did not differ among fertilized treatments. Directly measured
N2O emissions were significantly lower with PCU-1 than CSA. Fertilizer induced
emissions were relatively low, ranging from 0.10 to 0.49% of applied N. Indirect N2O
emissions, estimated using the IPCC default emission factor of 0.75% of NO3
were significantly lower than direct emissions. However, due to uncertainty, indirect
emissions could be anywhere from 0.6 to 84.9% of direct. These results show that PCU can potentially reduce N2O emissions. However, results are product specific and work
remains to be done in narrowing the indirect emission factor uncertainty range.
University of Minnesota M.S. thesis. April 2011. Major: Plant Biology. Advisor: Rodney T. Venterea. 1 computer file (PDF); viii, 154 pages.
Hyatt, Charles R..
Direct and indirect nitrous oxide emissions from controlled release and conventional fertilizers applied to potatoes in coarse textures soil..
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