Author:
ALLISON M. F.,ARMSTRONG M. J.,JAGGARD K. W.,TODD A. D.
Abstract
Between 1989 and 1993, 17 experiments tested the
effect of cover crop species, sowing date and
destruction date on cover crop dry matter (DM) yield, N
uptake and on soil mineral nitrogen (SMN)
content. All the experiments were carried out in Suffolk,
Norfolk, Lincolnshire and Yorkshire on
sandy-loam textured soils after crops of cereals or
oilseed rape had been harvested. The largest DM
yields were obtained with early sowings and averaged
1·6 t/ha. Cover crop N uptake was less
dependent upon sowing date and averaged 35 kg N/ha.
The average reduction in SMN was from 46
to 32 kg N/ha. Differences between cover crop species
were small when compared with season/site variations.Cereal cover crop DM yields were closely related to the
thermal time accumulated from the first
significant rainfall after sowing, whilst the yields of
non-cereal cover crops were more affected by the
moisture content of the soil at sowing. The amount of
SMN in the soil at sowing had little or no effect
on cover crop yield. The yields of cereal cover crops were
much more predictable than those of non-cereal cover
crops. Water usage by cover crops was estimated to be
20 mm/t DM and large cover
crops delayed the onset of leaching and reduced the
amount of water leached. However, even in dry
autumns and winters, soils are likely to reach field
capacity before the following beet crop is sown.
Due to their large C[ratio ]N ratio (20[ratio ]1) little
N would be mineralized after cover crop destruction. Cover
crops comprising volunteer cereals and weeds often
performed as well as the other cover crops and
in most cases will be the most cost-effective cover crops.
Publisher
Cambridge University Press (CUP)
Subject
Genetics,Agronomy and Crop Science,Animal Science and Zoology
Cited by
21 articles.
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