The main reason for the development of the yield gap in crop production is the inefficient management of nitrogen (N). The nitrogen gap (NG) cannot be ameliorated without an indication and quantification of soil characteristics that limit N uptake by a crop plant. The insufficient supply of N to a plant during its cardinal stages of yield formation is a result of two major-variabilities. The first is spatial variability in the soil characteristics responsible for water supply to a plant, also serving as a nutrient carrier. The second is a vertical variability in soil factors, decisive for pools of available nutrients, and their in-season accessibility to the grown crop. The long-term strategy for NG cover should focus first on soil characteristics (humus stock, pH, nutrient content) responsible for water storage and its availability to the currently grown plant. Diagnostics of plant nutrient availability should deliver data on their contents both in the topsoil and subsoil. The combined use of both classical diagnostic tools and spectral imagery is a way to divide a single field into units, differing in productivity. Remote-sensing techniques offer a broad number of tools to define the in-season crop canopy requirement for fertilizer N in homogenous field units.

中文翻译：

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氮差距改善是农业可持续集约化的核心概念

作物生产中出现产量缺口的主要原因是氮素管理效率低下。如果没有指示和量化限制作物吸收氮的土壤特性，就无法改善氮缺口（NG）。在产量形成的基本阶段，植物对氮的供应不足是两个主要差异的结果。首先是土壤特征的空间变异性，负责向植物供水，也可作为营养载体。第二个因素是土壤因子的垂直变化，这决定了可利用的养分池，以及它们在季节对作物的可及性。NG覆盖的长期策略应首先关注土壤特性（腐殖质，pH，营养成分）负责水的储存及其对当前种植植物的可用性。对植物养分有效性的诊断应提供表层土壤和下层土壤中其含量的数据。经典诊断工具和光谱图像的结合使用是一种将单个场划分为多个单位的方法，生产率各不相同。遥感技术提供了广泛的工具来定义均质田间单元中肥料N的季节作物冠层需求。