Potato belongs to the category of the staple food playing an important role in global food security and nutrition. Because potato plants have a shallow root system and stop nitrogen uptake early in the growing season (between 20 and 60 days after emergence), potato fields are more prone to leaching of nitrate to lower soil layers and the groundwater than deep rooting crops, thus posing a higher risk for polluting the environment with nitrate. On the other hand, lowering fertilizer dosages could result in yield loss and reduced tuber quality. To balance the risk of yield and quality loss against the risk of nitrate leaching, the fertilization dose should be adapted to the local production potential, which can vary considerably within a field. However, there is no consensus on how to adapt the fertilization to this variability. Therefore, the objective of this study was to assess various N fertilization scenarios and their effect on the concentration of residual nitrate, total potato yield and tuber quality. Five potato fields located in Flanders with historical spatial variation in crop productivity were selected as potential candidates for implementing site-specific nitrogen management practice. The fields were divided into management zones based on variation visible in soil maps, maps of electrical conductivity, maps of vegetation indices and soil samples. Nitrogen was applied in three different dosages, including the conventional dose, and two reduced fertilization levels. Based on time series of vegetation indices, cumulative vegetation indices and pair-wise correlations between the vegetation index values obtained from Sentinel-2 satellite imagery (FAPAR, NDVI, FCOVER, LAI) only two fields of five showed temporal stability of the spatial management zones, while in three other fields the zone performance shifted depending on the weather conditions during the growing season. In the fields with stable zones, the lowest N fertilization levels in the areas with lower productivity potential resulted in a reduction of the concentration of leachable nitrates while total yield and potato tuber quality (dry matter and nitrogen content) did not change. For this type of fields with temporally stable zones, it was concluded to recommend reducing the nitrogen dosage in the zones with a lower productivity potential and high mineralization levels to limit nitrate leaching. In the fields where better performing zones change their location in wet and dry years, significant differences between treatments in the total potato yield, dry matter and nitrogen content in the tuber were also often detected. However, application of a low nitrogen dose during the first fertilization in one of the zones in such fields is not recommended as it is not yet known how the zones will behave the coming season, leading to a risk for underfertilization of these zones. Therefore, conventional fertilization remains the recommended practice in case the production potential of the zones depends on the weather during the growing season and is not yet known at the moment of fertilization. However, fertilizer fractions applied later during the growing season may be adapted to the crop development and actual weather conditions.

中文翻译：

---

马铃薯精确氮管理方案：对产量、块茎质量和土壤中收获后硝酸盐残留的影响


马铃薯属于主食类别，在全球粮食安全和营养中发挥着重要作用。由于马铃薯植株的根系较浅，并且在生长季节早期（出苗后 20 至 60 天之间）会停止氮吸收，因此马铃薯田比深根作物更容易将硝酸盐浸出到较低的土壤层和地下水中，因此硝酸盐污染环境的风险更高。另一方面，降低肥料用量可能会导致产量损失和块茎质量下降。为了平衡产量和质量损失的风险与硝酸盐浸出的风险，施肥剂量应根据当地的生产潜力进行调整，这在田地内可能会有很大差异。然而，关于如何使受精适应这种变化还没有达成共识。因此，本研究的目的是评估各种氮肥施用情景及其对残留硝酸盐浓度、马铃薯总产量和块茎品质的影响。位于佛兰德斯的 5 块马铃薯田被选为实施特定地点氮管理实践的潜在候选者。根据土壤图、电导率图、植被指数图和土壤样本中可见的变化，将这些田地划分为管理区。氮以三种不同的剂量施用，包括常规剂量，以及两种降低的施肥水平。 根据植被指数的时间序列、累积植被指数和从 Sentinel-2 卫星图像（FAPAR、NDVI、FCOVER、LAI）获得的植被指数值之间的成对相关性，只有两个字段的 5 个字段显示了空间管理区的时间稳定性，而在其他三个字段中，区域性能根据生长季节的天气条件而变化。在稳定区的田地中，在生产力潜力较低的地区，最低的氮肥水平导致可浸出硝酸盐的浓度降低，而总产量和马铃薯块茎质量（干物质和氮含量）没有变化。对于这类具有时间稳定带的油田，得出的结论是建议减少生产力潜力较低和矿化水平高的区域的氮剂量，以限制硝酸盐浸出。在丰水年和旱年表现较好的区域改变其位置的田地中，也经常检测到处理之间马铃薯总产量、干物质和块茎中氮含量的显著差异。然而，不建议在此类田地的某个区域进行第一次施肥期间施用低剂量的氮，因为尚不清楚这些区域在即将到来的季节将如何表现，从而导致这些区域存在施肥不足的风险。因此，如果保护区的生产潜力取决于生长季节的天气，并且在施肥时尚不清楚，则常规施肥仍然是推荐的做法。然而，在生长季节较晚时分施用的肥料分数可能会适应作物的生长和实际天气条件。