Nitrogen uptake of Brussels sprouts – a model validation.
To improve nitrogen (N) fertilizer recommendations for field vegetables, Feller and Fink (1996) developed a generic model to predict total N demand based on expected yield. The objective of this study was to validate this model by using independent data for Brussels sprouts (Brassica oleracea L. var. gemmifera), a crop with a high N demand and a long growing time when compared to other vegetable crops. A field experiment was carried out where three N fertilizer levels were tested in all combinations with three cultivars that were considered to differ in total yield and, thus, in N demand. In addition, three Brussels sprouts crops with different planting dates were monitored in a grower’s field.
The model overestimated N uptake for N-limiting conditions, but for optimally fertilized Brussels sprout crops measured and estimated N uptake showed a close correlation (r² = 0.96) when total yield was used as an input parameter for the model. Although the error of estimation (SE = 40 kg N ha-1) was considerable, studies with other vegetable crops using this model showed this error can be even higher if other tools such as look up tables were used for predicting N uptake.
Fink M; Feller, C. 2001 Nitrogen uptake of Brussels sprouts – a model validation. Journal of Horticultural Science & Biotechnology 76 (5), 615-619