Sweet potato (Ipomoea batatas L.) is a new tuber crop grown in Greece. It constitutes an innovative dietary component for both humans and animals, due to its nutritional properties. The cultivation of sweet potato focuses on the growth of both tubers and plants. Nitrogen is considered an essential element for almost all crops. This study set out to compare the effect of nitrogen inhibitors on yield components of sweet potato. In the literature, it is stated that in sweet potato cultivation nitrogen mainly affects the plants’ growth such as the tuber's yield and some quality characteristics such as dry matter and protein content. To furthermore explore this particular area, field experiments took place in West Greece, during the years 2018 and 2019. Several urea combination treatments were used in the experimental process. The treatments were urea (46-0-0), urea with urease inhibitor (UI), urea with nitrification inhibitor (NI), urea with double inhibitors (UI + NI) and control (without fertilizer) in a randomised complete block design. Leaf area index (LAI) was significantly affected by the fertilizer marking the highest value of 5.35 under urea + UI + NI treatment. Marketable yield was profoundly affected by the fertilizer in the experimental years and ranged from 18,180 to 23,230 Kg · ha⁻¹ whereas non-marketable yield was not affected by the fertilizer. A considerable impact of fertilizers was noticed on yield where the highest value was 30,923 Kg · ha⁻¹ under urea + NI + UI treatment. The percentage of nitrogen on tubers and upper parts was significantly affected by the fertilizers. Nitrogen markers, such as nitrogen use efficiency (NUE), nitrogen harvest index and nitrogen agronomic efficiency (NAE), were used to evaluate nitrogen release. A significant positive correlation was noticed between marketable yield and NUE (0.774). Also, the significant increase in yield showed a positive correlation with NAE (0.727). For yield components of sweet potato, the highest values were observed in urea with double inhibitors treatment in both experimental years.

中文翻译：

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甘薯作物（Ipomoea batatas L.）中尿素酶和硝化抑制剂对产量和氮素利用的评估

甘薯（番薯）L.）是在希腊种植的一种新型块茎作物。由于其营养特性，它构成了人类和动物的创新饮食成分。甘薯的种植侧重于块茎和植物的生长。氮被认为是几乎所有农作物的必需元素。这项研究着手比较氮抑制剂对甘薯产量构成的影响。在文献中指出，在甘薯栽培中，氮主要影响植物的生长，例如块茎的产量和一些品质特征，例如干物质和蛋白质含量。为了进一步探索这一特定领域，在2018年和2019年期间在西希腊进行了现场试验。在实验过程中使用了几种尿素联合处理方法。处理方法是尿素（46-0-0），随机完整区组设计中的尿素与脲酶抑制剂（UI），尿素与硝化抑制剂（NI），尿素与双重抑制剂（UI + NI）和对照（不含肥料）。叶面积指数（LAI）受肥料标记的影响最大，在尿素+ UI + NI处理下，肥料标记最高值为5.35。在实验年中，可销售的产量受到肥料的深远影响，介于18,180至23,230 Kg·ha^-1，而不可销售的产量不受肥料的影响。在尿素+ NI + UI处理下，肥料对产量的影响显着，最高值为30,923 Kg·ha ^-1。肥料对块茎和上部的氮含量影响很大。使用氮标记（例如氮利用效率（NUE），氮收获指数和氮农学效率（NAE））评估氮释放。注意到可销售收益率与NUE（0.774）之间存在显着的正相关。此外，单产的显着提高与NAE（0.727）呈正相关。对于甘薯的产量成分，在两个实验年中，尿素经双重抑制剂处理均达到最高值。