Improving potato productivity and mitigating nitrogen losses using enhanced-efficiency fertilizers: A global meta-analysis

Abstract

Potato is the largest non-cereal food crop in the world, and its sustainable production is critical for global food security. Enhanced-efficiency fertilizers (EEFs), when used in potato cropping systems, improve nitrogen use efficiency (NUE) and reduce nutrient losses, although the effectiveness of EEFs varies considerably with different management and environmental conditions. In this context, a meta-analysis of 56 studies (including 65 experimental sites) reported from across the world was conducted to evaluate the effects of EEFs (polymer-coated urea [PCU], nitrification inhibitor [NI], urease inhibitor [UI], and urease and nitrification inhibitors combined [NIUI]) on the yield, N uptake, NUE, and N losses (via nitrate [NO3−] leaching, ammonia [NH3] volatilization, and nitrous oxide [N2O] emissions) in potato fields. The yield responses to EEF application under different management and environmental conditions, including the N application rate, planting density, climatic conditions, and soil properties, were comprehensively analyzed. It was observed that, compared to the traditional fertilizer, EEFs reduced the N2O emissions by 0.3 kg N ha–1 (32.2%), NO3− leaching by 15.6 kg N ha–1 (35.1%), and N application rates by 32.8 kg N ha–1 (16.8%), without any yield loss. The UIs were the most effective in increasing the potato yield, N uptake, and NUE (by 7.6%, 12.1%, and 34.6%, respectively), while the NIs were most effective in reducing the N2O emissions (by 49.4%). In addition, PCU was most effective in reducing NO3− leaching and NH3 emissions, with an average reduction of 18.5% and 74.3%, respectively. Tradeoffs were observed between N2O reduction and potato yield improvement with the use of NI and UI. However, the potato yield did not improve significantly with the use of NI fertilizers. The agronomic benefits of EEFs were mainly dependent on potato yield, soil pH, N application rate, soil organic carbon content, soil total N, and soil texture. Therefore, it was inferred that the selection of an appropriate EEF application strategy based on the environmental conditions and implementing it with the corresponding N application rate was important.