Agriculture, based on chemical inputs of fertilisers, herbicides, insecticides and fungicides is promoted as “best practice agriculture” in many countries around the world. Not only is “best practice agriculture”, responsible for the world wide destruction of grasslands it is also responsible for many of the problems in human, animal and soil health. There may be other ways that we can feed the growing human population without destroying our farms and planet.
Concerns about the above problems and declining profitability, poor soil structure, dry land salinity, soil acidification and increasing numbers of herbicide resistance weeds have prompted over 2000 farmers throughout eastern, southern and Western Australia to adopt ‘Pasture Cropping’. ‘Pasture Cropping is also being adopted in many countries such as the USA, South Africa, Scandinavia and South America.
The year-round groundcover created by using ‘pasture cropping techniques, results in reduced wind and water erosion, improved soil structure, reduced weed numbers, increased nutrient availability and increased levels of soil organic carbon. The soil health benefits from plant root exudates and a large increase in organic matter derived from a mix of shallow rooted crops and deep-rooted perennial pastures are numerous and include large improvements of soil microbiology.
In an era when dry land salinity, soil acidification and loss of soil carbon are having increasing impacts on the productivity and profitability of farming enterprises, ‘Pasture Cropping’ is providing an option for addressing these issues.
Colin Seis and Daryl Cluff pioneered “pasture cropping” in 1993 and since that time, Colin has fine –tuned and improved the technique on Winona. Due to this it is now possible to grow many different types of winter and summer sown crops, without destroying the perennial pasture base. The practice has now spread to all states of Australia and in a growing number of countries worldwide.
What is pasture cropping?
‘Pasture Cropping’ is an innovative land management technique that enables annual crops to be grown opportunistically into dormant perennial pastures or pastures whose competitive capacity have temporarily been supressed by grazing ,and /or selective herbicides to enable the successful growth of annual crops.
In contrast to conventional cropping that is sown into bare soil or stubble, ‘Pasture Cropping’ creates and exploits temporary competitive niches in the root ecology of the perennial pastures to enable the optimal growth of the short term annual grain crop. ‘Pasture Cropping’ avoids the need to kill the competitive pastures prior to sowing the crop thereby maintaining living plant cover of the soil so as to enhance its biological health, water retention and their protection from wind and water erosion relative to conventional crop practices.
Colin Seis has seen the need for ‘fast tracking’ improvement in degraded soil and grassland as well as producing crops for human consumption and /or stock feed. Since 2010 he has been developing ‘multi species pasture cropping’ with the aim of producing better quality forage and improving soil health even more than single species pasture cropping does.
‘Multi species pasture cropping’ uses all of the methods used in ‘pasture cropping’ but with the addition of 10 or more compatible annual crops that are sown at the same time. The mix of species improves soil microbial health, soil structure, nutrient cycling, as well as producing excellent stock feed. It has the added advantage of being able to harvest a grain crop after the multi species crop is removed by grazing.
The rationale behind ‘Pasture Cropping’:
Farmers for centuries have either grown and grazed pastures or grown crops on bare soils or tilled seedbeds. To try to get the best of both, many farming systems have also integrated alternate cropping and ley regenerative pastures stages in their farm management plans. However this has required the periodic killing of the pastures by cultivation or bio-cides to allow crops to grow. Few have been able to integrate both in one perennial ecology and farming system.
This is because perennial pasture and crop systems operate via different ecological and competitive processes that are assumed to be incompatible with each other.
Whereas perennial grasses compete through maximizing their root soil interfaces to survive periods of stress, annual crop plants compete as pioneers, rapidly and opportunistically exploiting suitable soil niches to produce adequate seed for their survival when stresses return. While both strategies can be highly effective it may be difficult for one plant to compete through both.
However these distinct competitive strategies may enable farming systems to be designed where the two types of plants can co-exist synergistically in time and space to benefit soil health and plant production.
For the past 20 years Colin Seis from, Winona, Gulgong in central NSW, Australia has been at the forefront of refining and evaluating such ‘Pasture Cropping’ strategies. Outstanding results and benefits have been confirmed in these lead trials, including:
- High crop yields of up to 4 tonnes per hectare when oats were sown into grassland.
- Sustained high pasture and animal production from the periodically cropped land.
- Marked improvements in the structure of and carbon levels in the ‘Pasture Cropped’ soils with Carbon bio-sequestration rates of up to 9 tC/ha/annually, plus significant improvements in the water holding capacity, nutrient dynamics and natural capital value of the landscape.
- Marked improvements in the biodiversity and resilience of the pasture cropped lands enabling them to sustain relatively higher pasture and crop yields even under stress.
- Significantly reduced input costs and risks on farm in producing these outcomes thereby markedly improving the economic and social viability of these farming systems.