SA Graan Junie 2016

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CONSERVATION AGRICULTURE
41
June 2016
ON FARM LEVEL Conservation agriculture
Nurse crop
Summer annuals: Teff.
Winter annuals: Oats and annual ryegrass.
Table 1 shows an overview of the major pasture ley species that
serve as forage for animals (cattle, pigs, sheep, chickens and fish).
Conclusion
Pasture ley and cover crops offer many benefits to producers that
increase farm profitability and environmental sustainability. Each
pasture ley and cover crop has a niche or special purpose. Leg-
ume pasture ley and cover crops are typically used to improve soil
nitrogen levels. Grass pasture ley and cover crops are used to in-
crease soil organic matter, recycle excess nutrients and reduce
soil compaction.
Brassica crops are grown to loosen the soil, recycle nutrients and
suppress weeds. Some other cover crops are grown to suppress
insects, disease, weeds or attract beneficial insects. Therefore,
cover crops should be considered an integral part of any farming
system aiming to efficiently utilise nutrients, improve soil health
and increase farm profitability.
For more information, contact Dr Wayne Truter at wayne.truter@
up.ac.za, Prof Chris Dannhauser at
Dr Hendrik Smith at or Mr Gerrie Tryts-
man at
Literature
Hoorman, JJ, Islam, R and Sundermeier, A, 2009. Sustainable crop rotations with
cover crops. Fact Sheet SAG-9-09, Agriculture and Natural Resources: Ohio State
University, Extension.
Smith, HJ and Trytsman, G, 2011. The integration of livestock with conservation
agriculture. Veeplaas.
Truter, WF, Dannhauser, CS, Smith, H and Trytsman, G. 2014. Integrated crop and
pasture-based livestock production system. SA Graan/Grain.
Willey, RW. 1985.Evaluation and presentation of intercropping advantages. Experi-
mental Agriculture 2, 119 - 133.
CA CROPPING
SYSTEM TYPE
GROWING
PERIOD ADVANTAGES DISADVANTAGES
SUITABLE SPECIES
COMMONLY USED
DRY MATTER (DM) AND
MEAT PRODUCTION
(G/D)
Non-legume
forage crops
< 1 year Easy establishment.
Rapid production of
feed.
Enable rapid shift
between crop and
livestock production.
No nitrogen fixed.
Little effect on SOM.
Little disease break or
weed control benefits.
Temperate annuals:
Oats
Rye
Tuberous crops:
Radish
Fodder rape
Warm season annuals:
Forage sorghum
Babala
3 - 6 ton DM/ha
ADG: 800 - 900 g/d
4 - 6 ton DM/ha
ADG: 650 - 800 g/d
8 - 10 ton DM/ha
ADG: 500 - 600 g/d
Annual legumes < 1 year Boost soil nitrogen
available for subse-
quent crops.
Some disease and
weed management
benefits.
Enable rapid shifts
between crop and
livestock production.
Provide limited ground
cover.
Little effect on SOM.
Can be weeds in subse-
quent crops.
Summer:
Cowpea
Lablab
Velvet bean
Jack bean
Winter:
Vetch
Serradella
3 - 5 ton DM/ha
ADG: 550 - 650 g/d
Poisonous: Caution
2 - 3 ton DM/ha
ADG: 900 - 1 100 g/d
Perennial leg-
ume
1 - 4 years Boost soil nitrogen
available for subse-
quent crops.
Good for disease
and weed manage-
ment benefits.
Limited improvement in
SOM.
Lower cropping intensity.
Provide limited ground
cover.
Lucerne
Poor man’s lucerne
Butterfly pea
6 - 8 ton DM/ha
ADG: 650 - 750 g/d
Not very productive in
trials
ADG: 850 - 900 g/d
Tropical grasses 1 - 4 years
> 4 years
Reduce weed popu-
lations.
Provide good ground
cover.
Increase in soil or-
ganic matter (SOM)
greater than for pure
legume or annual
forages.
Lower cropping intensity Grasses (summer):
Smuts finger
Rhodes grass
Wool grass
Buffalo grass
Bahia grass
Weeping love grass
8 - 10 ton DM/ha
ADG: 480 - 600 g/d
Tropical grasses/
legume mixtures
> 4 years Better utilisation of
resources.
Nutritionally bal-
anced forage.
Saving on
N fertilisers.
Less N fixed and available
as in pure legumes.
Difficulties controlling
persistent pastures in
subsequent crops.
Legumes:
Lucerne
Poor man’s lucerne
10 - 12 ton DM/ha
ADG: 600 - 750 g/d
TABLE 1: FUNCTIONS OF DIFFERENT PASTURE LEYS IN INTEGRATED CROP-LIVESTOCK SYSTEMS (DRYLAND).
Adapted from Smith and Trytsman, 2011