Evaluating the Effects of Reduced N Application, a Nitrification Inhibitor, and Straw Incorporation on Fertilizer-N Fates in the Maize Growing Season: A Field <sup>15</sup>N Tracer Study
Reducing fertilizer-N rate, applying a nitrification inhibitor (NI), and incorporating straw are widely recommended to improve N use efficiency of crops and decrease N losses. A field <sup>15</sup>N tracer study was conducted to compare their effectiveness on fertilizer-N fates during th...
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| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-07-01
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| Series: | Nitrogen |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2504-3129/5/3/39 |
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| Summary: | Reducing fertilizer-N rate, applying a nitrification inhibitor (NI), and incorporating straw are widely recommended to improve N use efficiency of crops and decrease N losses. A field <sup>15</sup>N tracer study was conducted to compare their effectiveness on fertilizer-N fates during the maize growing season in Northeast China. The following six treatments were used: (1) no N fertilization (control); (2) 200 kg urea-N ha<sup>−1</sup> (100%N); (3) 200 kg urea-N ha<sup>−1</sup> and straw (100%N + S); (4) 160 kg urea-N ha<sup>−1</sup> (80%N); (5) 160 kg urea-N ha<sup>−1</sup> and NI (Nitrapyrin in this study) (80%N + NI); and (6) 160 kg urea-N ha<sup>−1</sup>, NI, and straw (80%N + NI + S). The results showed that the five N fertilization treatments yielded 16–25% more grain and 39–60% more crop N uptake than the control, but the differences among the five treatments were not statistically significant. Compared with the 100%N, 20% fertilizer-N reduction (80%N) decreased the <sup>15</sup>N concentration in topsoil and plant pools but increased the proportion of plant <sup>15</sup>N recovery at harvesting (NUE<sub>15N</sub>, 60% vs. 50%). Compared with the 80%N, NI co-application (80%N + NI) delayed soil nitrification and increased soil <sup>15</sup>N retention at harvesting (52% vs. 36%), thereby decreasing NUE<sub>15N</sub> significantly. Straw incorporation decreased fertilizer-N retention in soil compared with NI co-application because it promoted NUE<sub>15N</sub> significantly. In conclusion, the results demonstrate that NI and straw additions are efficient strategies for stabilizing fertilizer-N in soils and potentially minimizing N loss; however, their effects on NUE<sub>15N</sub> vary and the related mechanism must be further clarified in long-term trials. |
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| ISSN: | 2504-3129 |