Farmer’s Weekly – 09 August 2019

The rotations also helped to
make systems more resilient
and drought-resistant.
According to Dr Johann Strauss,
a sustainable cropping system
scientist at the Western Cape
Department of Agriculture,
wheat yields averaged
approximately 500kg/ ha on
the farm during the 2003
drought, but averaged around
2,1t/ ha during the 2015
drought and 2,4t/ha during
the 2017 drought, described
by many as one of the worst
experienced in the Swartland.
Strauss explains that the
use of crop rotation helps to
boost yield by improving soil
health and structure, breaking
disease cycles and giving
farmers an opportunity to better
manage weed problems.
But, he warns, it is no silver
bullet, and must be used as
part of a conservation farming
system. In other words, it
should be used in conjunction

withreducedtillage,stubble

retentionand/orcovercrops.

thelivestockfactor

Includinganimalsinthe

systemalsohasa numberof

advantages,accordingtoStrauss.

Animalsaddsignificantvalue

torotationsthatincludelegume

pastures,suchaslucerneand

medics,byenablingthecrops

topaytheirwayonthefarm

whilediversifyingfarmrisks.

“Covercropsareobviously

notthesameasa feedmixyou

buyfromtheshop,butcan

helptosignificantlyreduce

feedcosts,”saysStrauss.

Althoughsomefarmersarenot

infavourofanimalsgrazing

theirlandsastheyfearthis

mayleadtocompaction,trials

atLanggewensshowthatit is

bettertohaveanimalsgraze

pasturesthantomakehay

fromthesepastures.Thisis

becausegrazingleavesmore

plantmaterialbehind.

“Youneedtoleaveatleast30%

to50%oftheplantmaterial

togetthebestresultsoutof

yourconservationfarming

efforts,”notesStrauss.

Animalsmayalsohelpto

reduceweedproblemsand

recyclecovercropnutrients

whengrazingpastures.

Cattlearegenerallyeasierto

runthansheep,astheycangraze

covercropsata laterstage.

iNtercroPPiNG

The international push for

more eco-friendly farming

systems that restore natural

ecosystem services has resulted

in a growing awareness of the

importance of biodiversity

above and below the ground,

and its importance for farm

sustainability, says Strauss.

This, in turn, has led to the

promotion of concepts such

as intercropping, where two

crops such as peas and canola

are planted in alternating

ABOVE:

Lucerne may

be planted to

increase the length

of a rotation.

INSET LEF T:

Dr Johann Strauss

is a sustainable

cropping system

scientist at the

Western Cape

Department of

Agriculture.

INSET RIGHT:

Legumes such as

lupines fix nitrogen,

so that less of the

element needs

to be applied to

follow-up crops.

photos: Glenneis Kriel

9 AUGUST 2019 farmer’sweekly 47