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Introduction
Durum wheat, a crucial staple crop, is confronted with escalating fertilizer usage, particularly nitrogen, to meet the surging demands of a growing population. However, the mismanagement of nitrogen to fulfill crop requirements can inflict harm on ecosystems, spark conflicts, and disrupt supply chains. In response to this challenge, precision fertilization technologies, specifically variable-rate fertilization based on satellite imagery, are being explored to optimize nitrogen (N) fertilizer efficiency in no-till durum wheat cultivation.
Materials and methods
Conducted over four consecutive growing seasons, from October 2018 to July 2022, the experiment took place in Asciano, Siena, Italy, on soil maintained under no-till conditions. Sowing was executed using a "disc-type furrow opener Vella VSD3200A No-till seeder". Four N fertilization approaches were assessed: a uniform N rate conventionally calculated, and three variable rates based on Sentinel-2 L2A spectral bands. These variable-rate approaches encompass one utilizing the Nitrogen Nutrition Index (NNI) (Fabbri et al., 2020), a proportional NDVI-based estimate (NDVIH), and a compensative NDVI-based estimate (NDVIL). The treatments were applied according to a strip-plot design in three block. The surface area of the experimental units ranged from 0.27 to 0.4 hectares over the four growing seasons. Analyzed parameters related to grain yield and kernel quality, protein partitioning, and dough rheology (Guerrini et al., 2020). For the four N fertilization strategies, economic analysis was conducted following the methodology outlined in Fabbri et al. (2023). Further, the carbon footprint was assessed in accordance with the ISO 14044:2006 guidelines.
Results and discussion
The study findings indicate that the NDVIL strategy, while enhancing protein and gluten levels, does incur at cost of yield compared to the uniform N rate. Indeed, the application of High-N fertilizer resulted in noteworthy increases in protein, specifically glutenin (Guerrini et al., 2020; Mancini et al., 2024). Conversely, the NDVIL strategy proves advantageous, increasing both grain yield and protein composition compared to the uniform N rate. In contrast, the NNI strategy, based on satellite imagery, demonstrates promising results by significantly reducing nitrogen usage without compromising grain yield or quality. Moreover, the NNI approach optimizes protein partitioning and dough technical properties, essential factors for various end-use applications. Regarding nitrogen fertilizer use efficiency (NfUE), the NNI strategy consistently outperforms other approaches. Notably, among the tested strategies, only the NNI significantly reduces the carbon footprint of cultivation, exhibiting a decrease of approximately 20 gCO2eq per kg of grain produced (-7.6%) compared to the uniform N rate. Furthermore, the economic analysis underscores the advantages of the NNI approach, showcasing lower social costs and higher rates of return compared to alternative nitrogen treatments. This underscores the economic and environmental sustainability of precision fertilization techniques, particularly the NNI strategy, in durum wheat cultivation.
Conclusion
This research not only advances our understanding of how various N treatments impact durum wheat production but also provides valuable insights across multiple dimensions of this intricate relationship. These dimensions encompass not only yield and protein composition but also extend to dough properties and economic considerations. The findings collectively provide valuable insights for the practical implementation of satellite-based N fertilization strategies, emphasizing the potential long-term benefits and sustainability of the NNI approach in promoting precision agriculture for durum wheat cultivation.
References
Fabbri, C., Basso, B., Napoli, M., Dalla Marta, A., Orlandini, S., Martinez-Feria, R.A., 2023. Developing a tactical nitrogen fertilizer management strategy for sustainable wheat production. European Journal of Agronomy 144, 126746. https://doi.org/10.1016/J.EJA.2023.126746
Fabbri, C., Mancini, M., dalla Marta, A., Orlandini, S., Napoli, M., 2020. Integrating satellite data with a Nitrogen Nutrition Curve for precision top-dress fertilization of durum wheat. European Journal of Agronomy 120, 126148. https://doi.org/10.1016/J.EJA.2020.126148
Guerrini, L., Napoli, M., Mancini, M., Masella, P., Cappelli, A., Parenti, A., Orlandini, S., 2020. Wheat Grain Composition, Dough Rheology and Bread Quality as Affected by Nitrogen and Sulfur Fertilization and Seeding Density. Agronomy 2020, Vol. 10, Page 233 10, 233. https://doi.org/10.3390/AGRONOMY10020233
Mancini, M., Guerrini, L., Fabbri, C., Orlandini, S., Napoli, M., 2024. Understanding the impact of within-field Olsen P variation on common wheat production in Olsen P deficient soils. J Agric Food Res 15, 101007. https://doi.org/10.1016/J.JAFR.2024.101007
| Keywords | Variable-rate fertilization; Life Cycle Assessment; N fertilizer use efficiency; Social cost; Dough technical properties |
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