G. Richard et al., DIRECT DRILLING OF SUGAR-BEET (BETA-VULGARIS L) INTO A COVER CROP - EFFECTS ON SOIL PHYSICAL CONDITIONS AND CROP ESTABLISHMENT, Soil & tillage research, 34(3), 1995, pp. 169-185
Direct drilling of sugar beet (Beta vulgaris L.) into an autumn sown c
over crop may reduce field work in spring and environmental damage, su
ch as soil erosion and nitrate leaching, but the balance of its negati
ve and positive effects on crop establishment is unknown, This study c
ompared the effects of drilling sugar beet directly into a cover crop
of wheat (Triticum aestivum L.) or rye (Secale cereal L.), or after co
nventional tillage in spring, on soil physical conditions and crop est
ablishment. The experiments were conducted over 4 years in the north o
f France on three soil types: chalky soil (rendzina), loam soil (calci
c cambisol) and silt loam soil (gleyic luvisol). Direct drilling cause
d less soil compaction than conventional drilling; the wheel tracks fo
r seed bed preparation were made in drier conditions for direct drilli
ng because of the change in tillage time (autumn for direct drilling v
s. spring for conventional drilling), Seed bed structure, temperature
and water content, and seed placement were very similar for the two dr
illing techniques (except in the silt loam soil) because of soil tilla
ge done by the sugar beet seed drill and removal of cover crop residue
s over the sugar beet rows. Final emergence percentage was lower with
direct drilling because of predator damage (by skylarks (Alauda arvens
is) and/or field mice (Apodemus sylvaticus)). Seedling growth after em
ergence was slower with direct drilling. The negative effects of direc
t drilling on sugar beet establishment may be counteracted by increasi
ng the seed density, or by its positive effects on soil structure and
consequently the possibility to sow sugar beet earlier. Because of its
environmental advantages, direct drilling of sugar beet into a cover
crop is an interesting technique for large farms with heavy work loads
in spring in areas where the soil has a high aggregate stability.