Al. Smit et al., ROOTING CHARACTERISTICS AND NITROGEN-UTILIZATION OF BRUSSELS-SPROUTS AND LEEKS, Biological agriculture & horticulture, 11(1-4), 1995, pp. 247-256
Under field conditions a crop of Brussels sprouts (Brassica oleracea,
var. gemmifera) usually utilises the plant-available nitrogen better t
han leeks (Allium porrum L.). To investigate the role of the root syst
em in nitrogen utilisation, the two crops were grown in the Wageningen
Rhizolab, a new rhizotron facility. Large differences in rooting patt
ern were observed. Leeks had a relatively shallow rooting system with
maximum root growth at a depth of 15 to 20 cm and a low rooting intens
ity. The rooting pattern of Brussels sprouts could explore the soil pr
ofile to a depth of one metre in a very short period. Large difference
s in nitrogen uptake pattern also showed up between the crops. Brussel
s sprouts depleted the entire rooted profile of nitrogen in a relative
ly short period (June to mid-August) whereas in leeks the nitrogen upt
ake was greatest in the second part of the season. The implications of
these rooting and nitrogen uptake patterns for fertilisation manageme
nt strategies to minimise N losses in ecological farming are discussed
.