t
he economic value, agricultural and soil conservation
benefits of pasture-based livestock production in crop
production systems are often underestimated and not well
quantified. The enormous pressure on crop production
areas to consistently produce good quality crops in a
sustainable manner is forever increasing.
Currently, most traditional agricultural practices (on both a small and
large scale) lead to severe land degradation and are climate change
negative, such as intensive tillage, which often results in greater
losses of soil organic matter, poor soil structure and available soil
moisture, and increased runoff and soil erosion.
This situation forces land users to consider more sustainable
land use options, such as conservation agriculture (CA). CA is an
approach to managing farms (or agro-ecosystems) for improved and
sustained productivity, increased profits and food security while
preserving and enhancing the resource base and the environment.
CA is characterised by three linked principles, which are supposed to
be implemented simultaneously, namely:
Continuous minimum mechanical soil disturbance.
Permanent organic soil cover.
Diversification of crop species grown in sequences and/or
associations.
In recent decades, the integration of livestock with CA systems
was perhaps among the most significant innovations in these
mixed production systems to ensure economic and ecological
sustainability and resilience while providing ecosystem services,
such as increased biological diversity, nutrient cycling and improved
soil health.
Livestock on improved pastures derived from CA-based crop-
pasture rotations not only produce more meat per unit of pasture,
they produce more per unit of greenhouse gas emission. Based on
these positive research results and experiences from producers and
other practitioners in the world (including the sub-Saharan Africa
region) during the last three decades, a new kind of sustainable,
intensified agriculture, based on CA, is emerging.
This series of articles to follow in the coming months will highlight
some of the pasture crop species that can play an imperative
role in CA-based crop-pasture rotations. Besides improving the
physical, chemical, hydrological and biological properties of the
soil, diversified cropping, including annual or perennial cover crops
(one of the main CA principles) can successfully be used as animal
feed. Actually, the majority of rotational and cover crop species
have already been used as animal feed, probably even before they
were known to improve soil properties. Furthermore, the presence
of livestock brings an additional source of life to the soil through
nutrients, microbes and soil aeration as a result of livestock hoof
action.
One of the key factors to consider before selecting a specific pasture
species is the suitability of the land (soil, topography and climate) for
the cultivation of the specific species.
What land qualities are required for successful cultivation of the
species? The next question to consider, is if the species need to
provide good quality hay, silage or green feed and what time of the
year would this be required?
Other than fodder production and preservation, it can also be
asked whether and when the pasture crop needs to be grazed,
and if so, which livestock type will utilise the pasture crop? This is
extremely important as stocking rates and grazing systems need to
be designed accordingly to protect the pasture crop from over- or
under-utilisation. This approach should however not be at the cost of
economical livestock production if this is regarded as the key driver
for utilising pasture.
The following aspects are similarly of key importance when
identifying the key pasture crop species for a particular use in CA.
Agro-ecological distribution
The suitability of different agro-ecological regions for cultivating
different species is of major importance. The species of interest
has to be evaluated to establish its suitability to specific climatic,
topographic and soil (land/edaphic) qualities.
Once the suitability is assessed, it can then be decided whether
additional ameliorative practices, such as fertilisation, liming or
irrigation are required to enhance the production of the selected
species. The suitability of species to the aforementioned land
Maart 2014
92
WAYNE TRUTER,
University of Pretoria,
CHRIS DANNHAUSER,
Grass SA,
HENDRIK SMITH,
Grain SA and
GERRIE TRYTSMAN,
ARC-Animal Production Institute
Integrated crop and pasture-based
livestock production systems
ON FARM LEVEL
Conservation agriculture
– Part 1
AGRICULTURE
Conservat ion
Series
