Cotton
profits increased by humble legume
Vetch, a little known legume, improves profitability of cotton
by increasing cotton yields by up to 18 per cent when grown in
rotation with cotton.
Results from 2003 trials show that when vetch is used the cotton
gross margin per hectare is increased by $390 within continuous
cotton rotation and by $270 in wheat cotton rotation.
About one third of the usual nitrogen fertiliser applied is needed
to maximise cotton lint yields in the cotton crop following vetch
and in some cases no nitrogen fertiliser is needed at all.
Vetch also increases soil organic matter, improves soil structure
making root penetration and cultivation easier, increases soil
water holding capacity and reduces the incidence of some fungal
diseases including black root rot.
Planted in February after a wheat crop or in May after cotton,
vetch is grown through winter, then slashed and ploughed into
the ground. The field can then be planted to cotton.
The
eight year CSIRO Plant Industry study demonstrated that although
vetch does not produce any direct income, it more than pays for
itself in the commercial benefits it provides while improving
soil fertility.
Like
most other rotational crops, vetch may increase fusarium wilt,
so fields should be carefully assessed before it is used.
This
research is supported by the Australian Cotton Cooperative Research
Centre and by cotton growers through the Cotton Research and Development
Corporation.
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