TY - JOUR
T1 - Adaptation of NO2− Extraction Methods to Different Agricultural Soils
T2 - Fine-Tuning Based on Existing Techniques
AU - Song, Yaqi
AU - Wu, Dianming
AU - Dörsch, Peter
AU - Yue, Lanting
AU - Deng, Lingling
AU - Liao, Chengsong
AU - Sha, Zhimin
AU - Dong, Wenxu
AU - Yu, Yuanchun
N1 - Publisher Copyright:
© 2024 by the authors.
PY - 2024/2
Y1 - 2024/2
N2 - Soil nitrite (NO2 −) is an important reactive intermediate in many nitrogen transformation processes, but it is unstable under acidic conditions and may be lost as gaseous N. The canonical extraction method of soil NO2 − using a potassium chloride (KCl) solution greatly underestimates its concentration. To reflect the concentration more accurately, we optimized the extraction method of soil NO2 − for three agricultural soils differing in soil texture and pH, an alkalic fluvo-aquic soil and acidic Mollisol and Ultisol soils, respectively. Both extractable soil ammonium (NH4 +) and nitrate (NO3 −) were systematically investigated to optimize the simultaneous extraction of soil inorganic nitrogen. The effects of different extractants (deionized water (DIW), un-buffered 2 mol L−1 KCl, and pH-buffered 2 mol L−1 KCl), shaking time (10 and 30 min), and storage duration of the extracts (stored at −20 °C for 1 day, and at 4 °C for 1, 3, and 6 days) on the determination of soil inorganic nitrogen were investigated. The results showed that the un-buffered KCl extractant significantly underestimated soil NO2 − concentration compared to DIW. The highest recovery of NO2 − was obtained by extracting with DIW at 10 min of shaking for all three soils. Compared with DIW, the concentration of NH4 + and NO3 − in soil extracted from the KCl solution increased significantly. Furthermore, the soil inorganic nitrogen content of extracts stored at 4 °C for one day was closer to the direct measurements of fresh samples than with the other storage methods. Overall, the recommended analysis method for soil NO2 − was extraction by DIW, shaking for 10 min, and filtering with a 0.45 µm filter, while soil NH4 + and NO3 − were extracted with a KCl solution and shaken for 30 min. The extract should be stored at 4 °C and analyzed within 24 h. Our study provides an efficient extraction method for soil NO2 − and supports studies on the biogeochemical nitrogen cycle, e.g., in the investigation of soil nitrous acid (HONO) and nitric oxide (NO) emissions.
AB - Soil nitrite (NO2 −) is an important reactive intermediate in many nitrogen transformation processes, but it is unstable under acidic conditions and may be lost as gaseous N. The canonical extraction method of soil NO2 − using a potassium chloride (KCl) solution greatly underestimates its concentration. To reflect the concentration more accurately, we optimized the extraction method of soil NO2 − for three agricultural soils differing in soil texture and pH, an alkalic fluvo-aquic soil and acidic Mollisol and Ultisol soils, respectively. Both extractable soil ammonium (NH4 +) and nitrate (NO3 −) were systematically investigated to optimize the simultaneous extraction of soil inorganic nitrogen. The effects of different extractants (deionized water (DIW), un-buffered 2 mol L−1 KCl, and pH-buffered 2 mol L−1 KCl), shaking time (10 and 30 min), and storage duration of the extracts (stored at −20 °C for 1 day, and at 4 °C for 1, 3, and 6 days) on the determination of soil inorganic nitrogen were investigated. The results showed that the un-buffered KCl extractant significantly underestimated soil NO2 − concentration compared to DIW. The highest recovery of NO2 − was obtained by extracting with DIW at 10 min of shaking for all three soils. Compared with DIW, the concentration of NH4 + and NO3 − in soil extracted from the KCl solution increased significantly. Furthermore, the soil inorganic nitrogen content of extracts stored at 4 °C for one day was closer to the direct measurements of fresh samples than with the other storage methods. Overall, the recommended analysis method for soil NO2 − was extraction by DIW, shaking for 10 min, and filtering with a 0.45 µm filter, while soil NH4 + and NO3 − were extracted with a KCl solution and shaken for 30 min. The extract should be stored at 4 °C and analyzed within 24 h. Our study provides an efficient extraction method for soil NO2 − and supports studies on the biogeochemical nitrogen cycle, e.g., in the investigation of soil nitrous acid (HONO) and nitric oxide (NO) emissions.
KW - deionized water
KW - potassium chloride
KW - shaking time
KW - soil nitrites
KW - storage time
UR - https://www.scopus.com/pages/publications/85187246423
U2 - 10.3390/agronomy14020331
DO - 10.3390/agronomy14020331
M3 - 文章
AN - SCOPUS:85187246423
SN - 2073-4395
VL - 14
JO - Agronomy
JF - Agronomy
IS - 2
M1 - 331
ER -