Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation Study
Urea granule dissolution in soil and soil urease activity are essential parameters for the accurate prediction of nitrogen dynamics after urea application, but both are scarcely studied. The response of urease activity to temperature is unclear under the addition of urease or nitrification inhibitor...
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MDPI AG
2022-11-01
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| Series: | Agriculture |
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| Online Access: | https://www.mdpi.com/2077-0472/12/12/2037 |
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| author | Kang Ni Andreas Siegfried Pacholski |
| author_facet | Kang Ni Andreas Siegfried Pacholski |
| author_sort | Kang Ni |
| collection | DOAJ |
| description | Urea granule dissolution in soil and soil urease activity are essential parameters for the accurate prediction of nitrogen dynamics after urea application, but both are scarcely studied. The response of urease activity to temperature is unclear under the addition of urease or nitrification inhibitors. In this study, we conducted laboratory incubation trials using glass jars with 100 g soil to quantify urea granule dissolution. Urease activity after urease and nitrification inhibitor addition were investigated in plastic bottles (5 g soil) under different temperatures. Inhibitor N-(2-nitrophenyl) phosphoric triamide (2-NPT), and a mixture of dicyandiamide and 1 H-1,2,4-triazol (DCD/HZ) were tested as urease and nitrification inhibitors separately and in combination. The dynamics of urease activity was fitted with Michaelis–Menten kinetics combined with the Van’t Hoff equation. At low soil moisture contents close to air-dry conditions (4–8% <i>w</i>/<i>w</i> water content), soil moisture was the dominant factor, but at higher soil moisture contents (28% and 48% <i>w</i>/<i>w</i>), temperature controlled the dissolution process. Dissolution could take several days or even longer at very dry soil conditions, while it was completed between a few hours and 24 h at high soil moisture levels. Urea with urease inhibitor formulation dissolved significantly slower at a moisture level of 28% (<i>w</i>/<i>w</i>). In the studied soil, urease activity varied between 2.9 and 54.4 mg NH<sub>4</sub><sup>+</sup>-N kg<sup>−1</sup> h<sup>−1</sup>. Across all urea concentrations, the addition of urease inhibitor 2-NPT significantly reduced urease activity. The relationship between urease activity and urea addition rate could be accurately described with Michaelis–Menten kinetics, and urease inhibitor addition reduced the temperature sensitivity of urease activity by 7%, while the nitrification inhibitor increased it by 4%. Parameter estimates and process characterization for urea granule dissolution and urea hydrolysis in this study are meaningful for and helpful in agricultural practice and the model simulation of soil nitrogen dynamics. |
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| issn | 2077-0472 |
| language | English |
| last_indexed | 2024-03-09T17:26:42Z |
| publishDate | 2022-11-01 |
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| series | Agriculture |
| spelling | doaj.art-21efc7e8a2164c7e9910d8ae5b99047b2023-11-24T12:40:15ZengMDPI AGAgriculture2077-04722022-11-011212203710.3390/agriculture12122037Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation StudyKang Ni0Andreas Siegfried Pacholski1Tea Research Institute, Chinese Academy of Agriculture Sciences, South Meiling Road 9, Hangzhou 310008, ChinaDepartment of Agronomy and Crop Science, Kiel University, Hermann Rodewald Str. 9, 24118 Kiel, GermanyUrea granule dissolution in soil and soil urease activity are essential parameters for the accurate prediction of nitrogen dynamics after urea application, but both are scarcely studied. The response of urease activity to temperature is unclear under the addition of urease or nitrification inhibitors. In this study, we conducted laboratory incubation trials using glass jars with 100 g soil to quantify urea granule dissolution. Urease activity after urease and nitrification inhibitor addition were investigated in plastic bottles (5 g soil) under different temperatures. Inhibitor N-(2-nitrophenyl) phosphoric triamide (2-NPT), and a mixture of dicyandiamide and 1 H-1,2,4-triazol (DCD/HZ) were tested as urease and nitrification inhibitors separately and in combination. The dynamics of urease activity was fitted with Michaelis–Menten kinetics combined with the Van’t Hoff equation. At low soil moisture contents close to air-dry conditions (4–8% <i>w</i>/<i>w</i> water content), soil moisture was the dominant factor, but at higher soil moisture contents (28% and 48% <i>w</i>/<i>w</i>), temperature controlled the dissolution process. Dissolution could take several days or even longer at very dry soil conditions, while it was completed between a few hours and 24 h at high soil moisture levels. Urea with urease inhibitor formulation dissolved significantly slower at a moisture level of 28% (<i>w</i>/<i>w</i>). In the studied soil, urease activity varied between 2.9 and 54.4 mg NH<sub>4</sub><sup>+</sup>-N kg<sup>−1</sup> h<sup>−1</sup>. Across all urea concentrations, the addition of urease inhibitor 2-NPT significantly reduced urease activity. The relationship between urease activity and urea addition rate could be accurately described with Michaelis–Menten kinetics, and urease inhibitor addition reduced the temperature sensitivity of urease activity by 7%, while the nitrification inhibitor increased it by 4%. Parameter estimates and process characterization for urea granule dissolution and urea hydrolysis in this study are meaningful for and helpful in agricultural practice and the model simulation of soil nitrogen dynamics.https://www.mdpi.com/2077-0472/12/12/2037urease activitytemperature sensitivitysoil moisturenitrification inhibitorurease inhibitor |
| spellingShingle | Kang Ni Andreas Siegfried Pacholski Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation Study Agriculture urease activity temperature sensitivity soil moisture nitrification inhibitor urease inhibitor |
| title | Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation Study |
| title_full | Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation Study |
| title_fullStr | Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation Study |
| title_full_unstemmed | Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation Study |
| title_short | Soil Moisture and Temperature Effects on Granule Dissolution and Urease Activity of Urea with and without Inhibitors—An Incubation Study |
| title_sort | soil moisture and temperature effects on granule dissolution and urease activity of urea with and without inhibitors an incubation study |
| topic | urease activity temperature sensitivity soil moisture nitrification inhibitor urease inhibitor |
| url | https://www.mdpi.com/2077-0472/12/12/2037 |
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