Multifactor effects on the N2O emissions and yield of potato fields based on the DNDC model

Abstract

Maintaining or increasing grain yields while also reducing the emissions of field agricultural greenhouse gases is an important objective. To explore the multifactor effects of nitrogen fertilizer on nitrous oxide (N₂O) emissions and the yield of potato fields and to verify the applicability of the denitrification-decomposition (DNDC) model when used to project the N₂O emission load and yield, this research chooses a potato field in Shenyang northeast China from 2017 to 2019 as the experiment site. The experiment includes four nitrogen levels observing the emission of N₂O by static chamber/gas chromatograph techniques. The results of this study are as follows: (1) DNDC has a good performance regarding the projection of N₂O emissions and yields. The model efficiency index EFs were 0.45 ~ 0.88 for N₂O emissions and 0.91, 0.85, and 0.85 for yields from 2017 to 2019. (2) The annual precipitation, soil organic carbon, and soil bulk density had the most significant influence on the accumulated N₂O emissions during the growth period of potatoes. The annual precipitation, annual average temperature, and CO₂ mass concentration had the most significant influences on yield. (3) Under the premise of a normal water supply, sowing potatoes within 5 days after the 5-day sliding average temperature in this area exceeds 10℃ can ensure the temperature required for the normal growth of potatoes and achieve the purpose of maintaining and increasing yield. (4) The application of 94.5 kg·hm^-2 nitrogen and 15 mm irrigation represented the best results for reducing N₂O emissions while also maintaining the yield in potato fields.

Keywords: DNDC model; Emission reducing; N2O; Potato; Sensitivity test; Yield.