Bioactive compounds, total antioxidant capacity and yield of kiwiberry fruit under different nitrogen regimes in field conditions.

Actinidia arguta known as the 'kiwiberry' or 'mini kiwi' is relatively new among the cultivated berry species. Recent studies indicate the kiwiberry fruit could be an important source of many health-promoting compounds. A knowledge-based fertilisation concept was evolved to define optimal strategies for feeding Actinidia with nitrogen (N) since a deficit and excess of N both have a negative impact on plants and the surrounding environment.Kiwiberry yield and fruit internal quality significantly depended on soil N level, cultivar and growing season. Higher soil N led to carotenoid content increase and phenolic content decrease while ascorbic acid and glutathione contents were not affected by soil N fertility. Under the highest N dose enzymatic antioxidants were activated. Trolox equivalent antioxidant capacity clearly decreased with an increasing N level.Competent and skilful fertilisation management should focus on balancing a high fruit yield and maintaining their high quality. Based on yield level, fruit antioxidant potential, the N guide values for A. arguta vary between 30 and 50 mg N per kg of soil. The recommended N dose may depend on overall soil quality traits, cultivar N demand, as well as weather conditions. This article is protected by copyright. All rights reserved.