Abstract

Site-specific nitrogen management has been proposed as a tool to increase crop yield while decreasing nutrient losses to the environment. Many reports can be found on sensing technologies to quantify the variability within a field and the definition of management zones based on the observed variability. However, fewer studies have been dedicated to the selection of the most suitable N fertilizer management scenario: should more or less nutrients be applied in the zones with a lower crop productivity potential? To address this knowledge gap, nine Flemish maize fields were selected as potential candidates for precision fertilization based on the soil maps and historical vegetation index patterns. Within each field, two management zones were identified based on historical vegetation index patterns and electrical conductivity maps, and different fertilization strategies were tested in each zone. The field trial results in terms of yield and soil residual nitrate showed that site-specific N management outperforms the conventional practice only in the fields with temporally stable management zones. In the fields having differences in the physical soil properties (e.g. presence of stones or clay particles), affecting water availability, lower fertilization in zones with a poor soil productivity potential could be recommended. In the fields where the performance of the management zones changes from year to year mainly due to annual variation in precipitation, a risk of incorrect implementation of the precision fertilization concept was identified. Historical NDVI time series serve a good basis to delineate the temporally stable management zones.

中文翻译：

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通过精准氮肥管理，有可能在不牺牲产量的情况下减少玉米田收获后的硝酸盐残留

摘要

已提出针对特定地点的氮管理作为提高作物产量同时减少养分流失到环境中的工具。可以找到许多关于传感技术的报告，用于量化田地内的变异性以及根据观察到的变异性定义管理区域。然而，致力于选择最合适的氮肥管理方案的研究较少：在作物生产力潜力较低的地区是否应该施用更多或更少的养分？为了解决这一知识差距，根据土壤图和历史植被指数模式，选择了九个佛兰德玉米田作为精准施肥的潜在候选者。在每个田地内，根据历史植被指数模式和电导率图确定了两个管理区，并在每个区测试了不同的施肥策略。田间试验结果显示，在产量和土壤残留硝酸盐方面，定点施氮管理仅在具有暂时稳定管理区的田地中优于常规做法。在土壤物理性质存在差异（例如存在石头或粘土颗粒）的田地中，会影响水的可用性，建议在土壤生产力潜力较差的地区减少施肥量。在管理区绩效逐年变化的田地中，主要由于降水量的年变化而变化，发现了精准施肥理念实施不正确的风险。历史 NDVI 时间序列为划定暂时稳定的管理区提供了良好的基础。