甘薯氮素营养研究进展
Research Advances of Nitrogen Nutrition in Sweet Potato

氮是甘薯生长发育必需的营养元素之一，也是影响其生长发育、产量及品质形成的关键因素。就甘薯氮素吸收与分配特性，不同甘薯品种氮素利用特性差异，施氮对甘薯氮素吸收利用、物质生产、根系分化、产量和品质的影响以及甘薯植株氮素营养诊断等方面进行综述，以期为甘薯氮素营养研究提供参考和借鉴。综合分析认为，不同气候条件下甘薯的适宜施氮量及不同甘薯品种的氮素利用特性存在差异；施氮可显著影响甘薯对氮素的吸收利用，过量施氮不利于甘薯光合特性的改善，明显抑制块根的形成，降低块根产量和氮素利用效率；通过甘薯氮素营养诊断，初步确立叶片为甘薯氮素营养诊断的适宜部位，提出甘薯叶片正常氮素质量分数及氮素亏缺的适宜参考值。今后研究应从改进氮肥施用方式（如氮肥追施、不同深度施肥）、甘薯农田氮素循环及氮素损失途径、适量减氮（或不施氮）不减产、氮高效品种筛选及其机理、甘薯氮素诊断标准（如最佳测试时期及测试部位）体系、甘薯氮素实时监控技术体系及施肥模型等方面进行深入研究。
Nitrogen is an essential element for sweet potato,which plays an important role in its growth,yield and quality. In order to provide a reference for further nitrogen nutrition research in sweet potato,the nitrogen nutrition characteristic of sweet potato was summarized according to some relevant literature in this article,which included the nitrogen absorption characteristics of sweet potato,the nitrogen use characteristics of different sweet potato cultivars,effects of nitrogen fertilizer on nitrogen absorption,dry matter production,root differentiation,yield and quality. Comprehensive analysis reveals that the suitable nitrogen application rate and nitrogen use characteristics of different sweet potato varieties were different under different climate conditions. Nitrogen application significantly affects nitrogen absorption and utilization in sweet potato. Excessive nitrogen application was not conductive to improve photosynthetic characteristics of sweet potato,whereas significantly inhibits tuber root formation and expansion. It also reduces tuber yield and nitrogen use efficiency and causes root quality deterioration. For the study of nitrogen nutrition diagnosis of sweet potato,The researchers have determined that the leaf proved to be the optimum location for the nitrogen nutrition diagnosis in sweet potato,and also proposed the suitable reference values for normal nitrogen contents and nitrogen deficit in sweet potato leaves. The future research should targeted on application methods of nitrogen fertilizer (such as nitrogen topdressing,different nitrogen application depth),nitrogen cycling and nitrogen loss pathways in sweet potato planting fields,reasonable reducing nitrogen application (no nitrogen application) without yield reduction,screening for nitrogen efficient sweet potato varieties and the mechanism of high nitrogen efficiency,nitrogen diagnosis standard system for sweet potato (such as the optimal testing time and location),establishing nitrogen real time monitoring system and nitrogen fertilizer application model for sweet potato.