Agriculture Reference
In-Depth Information
Figure 4.19
AvigorouscovercropofwintercerealintheWesternCapeProvince
region,SouthAfrica.
kikuyu, as shown in figure B2.7.1, chapter 2, provides maximum competition
and vigor control.
Permanent grass cover crops decrease the amount of nitrogen available
to the vines and lessen the need for herbicides to control weeds. Except on
high-potential sites, as in the King Valley region, Victoria, Australia, for
example, permanent cover crops are not recommended for dry-grown vine-
yards, or those receiving minimal irrigation, because soil water needs to be
conserved during summer. For this reason, winter cover crops, which in spring
are mown or cultivated into the soil, are favored in many vineyards. Keeping
the mid-rows well mown or free of vegetation in spring and early summer
reduces
ET
, often improves crop yields, and reduces the risk of late frost dam-
age to the vines.
“Cover Crops and Mulches” in chapter 5 provides further details on cover
crop species and the effect of cover crops on soil biology.
Mulches, Soil Water, and Temperature
Whenacovercropismowninspring,themowingscanbethrownsidewaysto
form a mulch under the vines. Other organic forms of mulch include compost,
barkchips,andcerealstraw(igure4.20).About25m
3
ofmulch(approximately
