Tracing nitrogen utilization and distribution during development of grape seedlings by applying different forms of 15N labeled fertilizer with fruit tree hole storage brick

Abstract

The use of soil amendment has been boosted in the last years due to its possible influence on fertility, including its potential ability to lower mineral nitrogen (N) losses. However, yet little is known about the effects of different N forms combined with soil amendment on grape growth and NUE. In this study we have prepared fruit tree hole storage brick (FTHSB) suitable for perennial fruit trees, then recommended a new fertilization strategy combining different forms of N fertilizer with FTHSB. We investigated the transformation of N in soil, the N absorption in grape (Vitis vinifera L.), and the root growth in the grape at different treatment (Ammonium nitrogen (CKA), nitrate nitrogen (CKN), amide nitrogen (CKU) applied separately without FTHSB and ammonium nitrogen (TA), nitrate nitrogen (TN), amide nitrogen (TU) applied separately with FTHSB). The results showed that FTHSB significantly increased the dry matter mass of all organs of grape seedlings, fine root indexes in 15–30 cm soil layer, NR,GS enzyme activity, and soil urease activity in 15–30 cm soil layer. FTHSB increased the nitrogen fixation capacity of the soil by increasing the soil nitrogen content in the 15–30 cm soil layer.The highest soil nitrogen content was observed in the 15–30 cm soil layer under TU treatment. FTHSB significantly improved the nitrogen utilization efficiency of grapes. ¹⁵N isotope tracking technique showed that without FTHSB application, CKN treatment had the highest nitrogen utilization, which was 6.28 % and 6.01 % higher than CKA and CKU, respectively. However, after applying FTHSB, TU had the best effect, which was 15.61 % and 10.33 % higher than CKA and CKU. These results show that application FTHSB with CO(NH₂)₂-N can be used as a new fertilization strategy to sustainably improve the growth and NUE of grapes.