Enhanced-Efficiency Fertilizers Impact on Nitrogen Use Efficiency and Nitrous Oxide Emissions from an Open-Field Vegetable System in North China

Abstract

Open vegetable fields in China are a major anthropogenic source of nitrous oxide (N2O) emissions due to excessive nitrogen (N) fertilization. A 4 yr lettuce experiment was conducted to determine the impacts of controlled-release fertilizers (CRFs) and nitrification inhibitors (NIs) on lettuce yield, N2O emissions and net economic benefits. Five treatments included (i) no N fertilizer (CK), (ii) conventional urea at 255 kg N ha–1 based on farmers’ practice (FP), (iii) conventional urea at 204 kg N ha–1 (OPT), (iv) CRF at 204 kg N ha–1 (CU) and (v) CRF (204 kg N ha–1) added with NI (CUNI). No significant differences were found in the lettuce yields among different N fertilization treatments. Compared with FP, the cumulative N2O emissions were significantly decreased by 8.1%, 38.0% and 42.6% under OPT, CU and CUNI, respectively. Meanwhile, the net benefits of OPT, CU and CUNI were improved by USD 281, USD 871 and USD 1024 ha–1 compared to CN, respectively. This study recommends the combined application of CRF and NI at a reduced N rate as the optimal N fertilizer management for the sustainable production of vegetables in China with the lowest environmental risks and the greatest economic benefits.

Effects of Long-Term Controlled-Release Urea on Soil Greenhouse Gas Emissions in an Open-Field Lettuce System

“…In comparison with conventional urea, DCRU significantly decreased the GWP. The decrease in GWP under CRU and DCRU was mainly due to the reduced N 2 O emissions, which was in accordance with previous studies [ 16 , 18 , 27 ]. Therefore, the reasonable application of DCRU may be an important measure for slowing down GHG emissions from vegetable systems in the future.…”

“…CRU can better match fertilizer nutrient release with crop uptake without additional topdressing [ 10 , 12 , 13 ]. Previous meta-analyses indicated that CRU could be applied once as basal fertilizer with no effect on grain yields while reducing reactive N losses by 49% worldwide [ 14 ], thus decreasing the use of N fertilizer and promoting time- and labor-saving crop production [ 15 , 16 ]. The advantageous effects of CRU on grain yield and NUE depend largely on the synchronization of the N release rate with the N requirements of crops [ 10 ].…”

Effect of Urea-Calcium Sulfate Cocrystal Nitrogen Fertilizer on Sorghum Productivity and Soil N2O Emissions

“…Significant research efforts have thus been dedicated to stabilizing urea in the environment via the design of various chemically stabilized urea condensation polymers, such as ureaforms, that confine urea into a polymeric structure, urease enzyme inhibitors that delay urea hydrolysis, nitrification inhibitors that reduce the activity of nitrifying bacteria, and polymer-or sulfur-coated fertilizers that utilize a partially permeable coating material for controlled N release [19][20][21]. While using enhanced-efficiency fertilizers allows for better synchronization of N supply with crop N uptake [22], high associated costs and complex production processes remain significant obstacles in their wide use [23].…”