TY  - CHAP
U1  - Buchbeitrag
A1  - Frerichs, Christian
A1  - Daum, Diemo
T1  - Soil sampling depth for calculation of nitrogen base fertilization in field-grown spinach
T2  - Proceedings of the International Symposium on Plant Nutrition, Fertilization, Soil Management
N2  - Spinach is a nitrogen (N)-demanding crop characterized by a shallow root architecture. Especially in the first weeks after sowing, significant N uptake is limited to the uppermost few centimetres of the soil. However, base fertilization is usually based on the soil mineral N (Nmin) concentration in the upper 30 cm. Therefore, the objective of this study was to examine whether the soil sample depth for calculating the base N fertilization can be reduced to the 0-15 cm layer. In seven field trials, conducted during spring, summer and autumn seasons, either a low or high base fertilization dose was applied at sowing. Until top dressing, soil samples were frequently taken in the upper 0-15 and 15-30 cm layers to determine the average Nmin concentration in each layer. Top dressing was applied when the first true leaves had unfurled. With this fertilizer application, the total N supply was aligned between both treatments based on the Nmin concentration in the upper 30 cm of the soil. Aboveground fresh and dry masses were determined after reaching a fresh mass yield of 15-20 t ha‑1 and related to the mean Nmin concentration in the first 3 to 4 weeks of cultivation between sowing and top dressing. It was shown that the Nmin concentration in the upper 0-15 cm of the soil highly reflects the base fertilization rate. By contrast, the Nmin concentration in the 15-30 cm layer remained unaffected. However, the Nmin concentration of both top soil layers can affect fresh and dry mass yield at harvest. Therefore, the entire 0-30 cm soil layer should be considered when calculating the base N fertilization rate in field-grown spinach. Measurements revealed that spinach fresh and dry masses were increased until the N availability of between 54 and 59 kg ha‑1 (0-30 cm) was reached at the seedlings stage, respectively.
KW  - Spinacia oleracea L.
KW  - N min concentration
KW  - Base fertilization
KW  - Fresh mass yield
KW  - Dry mass yield
Y1  - 2023
SN  - 978-94-62613-74-4
SB  - 978-94-62613-74-4
U6  - https://doi.org/10.17660/ActaHortic.2023.1375.12
DO  - https://doi.org/10.17660/ActaHortic.2023.1375.12
N1  - XXXI International Horticultural Congress (IHC2022): International Symposium on Plant Nutrition, Fertilization, Soil Management, 14.08. - 20.02.2022, Angers (France)
SP  - 89
EP  - 96
PB  - International Society for Horticultural Science (ISHS)
ER  -