LEFT:
The roots of
triticale are slight,
but the plant is
nonetheless a
significant builder
of humus levels.“Two years ago, Abrie planted
a cover crop mixture between
his tomato cycles. It produced so
much plant material that I started
looking for a way to get it into
Abrie’s vineyards, which resulted
in the development of the planter.”
The use of cover crops has
been ingrained in Jordaan’s
family for many years, with
his father using them.
“In those days, farmers still used
flood irrigation, and later moved
irrigation lines to ensure that the
cover crops had access to enough
water. They usually produced
one grass species, such as triticale
or rye, and never achieved the
thick volumes of plant material
we saw with the mixture under
irrigation,” says Jordaan.
This year, he will plant cover
crops on 17ha, representing
about 80% of his land.
“We’re leaving the areas that
are difficult to reach and those
under new vines that still need
to be trellised,” he explains.less summer grass,
less herbicide required
At Idma Boerdery near Vredendal,
the cover crops created such a
thick mulch that owner Kleinjan
Teubes thinks he will be able
to forgo at least one routine
herbicide application this year.
“The cover crops basically
inhibit the germination of
summer grasses. So, in effect,
they pay their way through
herbicide savings,” he says.
The four vineyard rows where
he planted cover crops last year
had a considerably lower weed
stand on the ridges than the
vineyards without cover crops,
so he decided to expand the area
under cover crops to about 80%
of their farm, representing 90ha.
They are now observing the
same trend with the weeds.
“Our soils are so poor that
most of last year’s cover crop still
hasn’t broken down. Sheila Storey,
the owner of Nemlab [a nematode
diagnostic laboratory] told me
not to worry about this, however,
but to continue the course, as
the soil improvement wouldRenierEngelbrechtandhisson,Wilco,whofarmonKleinbegin,planteda covercrop
mixtureona tomatolandforthefirsttimelastyear.Renierexplainsthattheyhaveonly
25haunderfactory-processedtomatoes,soneedtomakethemostof theavailableland.
“Factorytomatoproducersgenerallycannotplanttomatoesonthesame
landformorethantwoyears.Afterthis,productionstartstodeclineandthey
runintoall kindsof diseaseproblems.In thepast,I’vebeenabletolengthen
theproductioncycletoeightyearsbyusingcompostteas,manuresand
organicacids.We’reexperimentingwithplantingcovercropsafterharvest
andbeforenewtomatoesareestablishedon7haof ourland,”hesays.
Wherethefarmusuallyaimstoproduce100tof tomatoesperhectare,they
producedanaverageof 125t/ha,withsomelandsproducingas muchas 175t/hain 2019.
In contrast,manyof theotherfarmersin theareastruggledtofilltheirquotas.
“I cannotsaythiswaspurelybecauseof thecovercrops,as thelandsalsolay
fallowlastyearduetotheclosureof thetomatofactorybecauseof thedrought,”
saysWilco.“Wealsodidn’tleaveanycontrolsagainstwhichtheresultscouldbe
measured.Evenso,I can’thelpbutthinkthecovercropsmadea hugedifference.”
Theywerealsoabletoreducenitrogenapplicationby10%to20%duetothehigher
vegetativegrowthof thetomatoplantswheretheyusedcovercrops.Theinternodes
of theseplantsweredoublethelengthof theplantsnotgrownaftercovercrops.
ThemainreasonstheEngelbrechtsstartedusinga mixtureof
covercropsweretointroducemorediversitytotheirproduction
systemandfindanalternativetochickenmanure.
“Weusedtoapplychickenmanuretothelandstobuildthesoilnutrientlevels,
buttransportingthemanurefromCapeTowntoVredendalmadethispractice
exorbitant.It nowcostsaroundR4000/ha just for the manure,” says Wilco.
The Engelbrechts hope that the strategic use of cover crops will help reduce
their need for chicken manure, and are also considering getting a few cattle to
graze the cover crops to add more value to the system through ultra-high-density
grazing. They already use humic acids and compost teas to build soil health.Results of cover cropping on a tomato farm
44 farmer’sweekly 9 august 2019
soil health Cover Crops