In a two-year field trial at the sites Ruthe (Germany, loess soil, Orthic Luvisol) and Schermer (The Netherlands, marine clay soil, Eutric Fluvisol) the cauliflower F1-hybrids Marine, Lindurian and Linford were compared in their efficiency of N use from limiting and optimum supplies of N. Limiting N was Nmin at planting. Optimum N was 250 kg ha—1 as the sum of inorganic N content of the soil (Nmin) at planting and fertilizer-N. Marine was the most efficient variety, producing the highest shoot dry-matter and quality (% class 1 curds) at both limiting and optimum N supplies. The N supply did not affect the horizontal and vertical distribution of root length density per soil volume (RLD, cm cm—3) irrespective of variety. The RLD decreased exponentially with increasing soil depth. Varietal differences in RLD were not found at Ruthe, whereas at Schermer Marine had the highest RLD in all soil layers investigated (0 to 60 cm). No correlations were found between RLD and residual Nmin at harvest, except at limiting N supply in Schermer where a strong negative correlation was found between RLD in the 45 to 60 cm layer and Nmin at harvest. Thus, varietal differences in N efficiency are speculated to be rather due to different internal N-use efficiency than to differences in N-uptake efficiency.
|Journal||Journal of Plant Nutrition and Soil Science|
|Publication status||Published - 2000|