Nitrogen (N) supply to the soil via fertilization can influence important processes of the root system growth, which can increase N uptake and, consequently, the shoot growth. In this context, the study aimed to evaluate how the application of N levels can affect the dynamics of spatial and temporal growth of the root system of grapevines (Vitis vinifera L.) in sandy soil and subtropical climate. ‘Alicante Bouschet’ grapevines, grafted on ‘Paulsen 1103’ rootstock, implanted in 2011. The N addition were: Low N: control (without the N addition; 0 kg N ha⁻¹ year⁻¹); Medium N (40 kg N ha⁻¹ year⁻¹); and High N (100 kg N ha⁻¹ year⁻¹). The study was carried out during 2016/17 and 2017/18 crop seasons. N concentration in the leaves and morphological parameters of fine roots were evaluated using the minirhizotron technique. The addition of Medium N and High N significantly increased the values ​​of the total surface area of ​​live fine roots and the total number of live and dead fine roots, at 0-20, 20-40 and 40-60 cm soil depth, in both crop seasons evaluated. The addition of Medium N and High N also directly influenced the production rates of live fine roots, with patterns of seasonal changes, especially increased in the flowering stage of the grapevines. This occurs due to the increase in the physiological demand of growing plant tissues, such as new roots, leaves and fruits.

Nitrogen (N) supply to the soil via fertilization can influence important processes of the root system growth, which can increase N uptake and, consequently, the shoot growth. In this context, the study aimed to evaluate how the application of N levels can affect the dynamics of spatial and temporal growth of the root system of grapevines (Vitis vinifera L.) in sandy soil and subtropical climate. ‘Alicante Bouschet’ grapevines, grafted on ‘Paulsen 1103’ rootstock, implanted in 2011. The N addition were: Low N: control (without the N addition; 0 kg N ha⁻¹ year⁻¹); Medium N (40 kg N ha⁻¹ year⁻¹); and High N (100 kg N ha⁻¹ year⁻¹）。该研究在 2016/17 和 2017/18 作物季节进行。使用 minirhizotron 技术评估叶片中的 N 浓度和细根的形态参数。中氮和高氮的添加显着增加了0-20、20-40和40-60 cm土壤的活细根总表面积和活细根总数和死细根总数的值深度，在两个作物季节评估。中氮和高氮的添加也直接影响活细根的产量，具有季节性变化的规律，特别是在葡萄开花期增加。这是由于生长中的植物组织（例如新的根、叶和果实）的生理需求增加所致。