Pasture cropping: Is it an option on your place?
By Regional Agricultural Landcare Facilitator Rohan Leach, April 2020
With glyphosate, fertiliser and other chemicals hard to source this year, some farmers may be considering pasture cropping in order to improve farm business turnover. However, before farmers launch into pasture cropping for the first time they should take note of some key considerations.
Pasture cropping can provide good quality feed in tired, thinning pastures. (Photo credit, Callan Thompson)
Pasture cropping in its current form has been undertaken since the 1990’s in Australia, however “sod-seeding” has been around since the 1960’s. The traditional aim of pasture cropping is to sow temperate cereals (wheat, barley, triticale and oats) into summer active native pastures (e.g. Red, Mitchell and Warrego grasses) to either bulk pastures up with winter forage or to opportunity harvest for grain at the end of the growing season. It is well suited to the central west as the region does not have a strong dominance of seasonal rainfall and means that pasture croppers can take advantage of rainfall at any time of the year.
In good years, mixed farmers undertaking pasture cropping are able to capitalise on rainfall to grow summer feed, autumn and temperate cereal forage and then lock up in late winter for a grain harvest or hay making. In years with less rainfall, winter cereals can simply be grazed out with production from forage only. Animals are then able to graze on summer pasture dependent on rainfall and pasture growth.
There are a number of successful pasture croppers based in the Central West with no “one-size-fits-all” technique used across every farm. For example, Colin Seis is well known across Australia for his innovative pasture cropping techniques. He highlights the profitability of the system rather than high production levels. By using low rates of fertiliser and chemical, he has dropped his costs substantially with only a small reduction in his output. He is able to lower his use of knockdown chemical inputs by utilising high impact grazing to reduce biomass (Seis, 2012).
The practise is best suited to soils with low water holding capacity or the lighter soil types (Badgery, 2009). This is because removal of the summer fallow does not largely affect crop production and in turn maintains groundcover on these fragile soils. These soils rarely sustain cropping phases for long periods due to inherent low fertility or low water storage capacity. Instead, farmers are able to maintain or introduce perennial pastures to help maintain soil structure and ensure the long term health of the soil while also having the opportunity to make money from the pasture crop.
It is where the pasture cropping system moves outside of these parameters of soil type and seasonal rainfall patterns that the largest limitations become apparent. Moisture and nutrients drive crop yields so growers thinking about pasture cropping should consider the impact this will have on their yields. In work performed at Wellington, NSW, the wheat yield of pasture cropping was consistently lower than that of no till cropping, with yields reduced by as much as half (Badgery, 2009). This is due to competition of resources, namely nitrogen and moisture.
However, while crop yield will be lowered, the profitability of the entire system may be much higher (Seis, 2012). Farmers should also look at the value of grazing over summer and the forage from the winter cereal to their enterprises. With high livestock prices at the moment, this can be of more value than the potential grain yield.
While some pasture croppers choose to limit fertiliser inputs, be conscious of the nutrient removal of your enterprise. For every dry matter (DM) tonne of grain or hay harvested per hectare, around 2-3 kg of Phosphorous (P) is also removed (Incitec Pivot Fertilisers, 2018), not to mention other nutrients like Nitrogen (N) and Sulfur (S). West of the Newell Highway, a sheep enterprise will typically be removing between 0.5-1kg P/ha per year while further east this figure can be as high as 1.5kg P/ha/year (Leech, 2009). This figure is dependent on rainfall and stocking rate.
Another aspect to consider is the sowing implement. Disk-seeders that offer minimal soil disturbance are advised however very narrow points or “lucerne renovators” can also be used on direct drill, tined implements. This reduced soil disturbance results in less damage to the perennial pasture species and improved growth rates.
Without high density grazing at your disposal, knockdown herbicides (paraquat/diquat or low rates of glyphosate) will need to be used where high densities of winter annual weeds are germinating. Damage to the summer perennials can be minimised by using these knockdowns during the cold winter months when these plants have shut down and growth rates are slow. Winter annuals will compete heavily with the sown crop and reduce grazing quality and virtually eliminate any chance of a grain harvest. Post-emergent grass sprays may need to be utilised as well.
Another benefit of the pasture cropping system is the increased soil carbon levels as a result of maintaining more biomass in the cropping system. Pasture cropped systems have similar soil organic matter levels to that of perennial pasture only systems, which are higher than cropping only soil systems (Badgery et al, 2014). This added soil carbon, which is built up over years of practising pasture cropping, results in increased nutrient and moisture holding capacity (Hoyle, 2013). As a rule, each one percentage increase in soil organic carbon increases water holding capacity of soils by around 2% (Hoyle, 2013). In the CW region, around 2% organic carbon levels in dryland situations are considered optimal.
See the examples below which highlight the situations that pasture cropping may be suited:
Example situation 1)
A 40 ha paddock near Condobolin on light soils with some granite ridges has been a native pasture for 10 years and uncultivated. There has been excellent growth over summer but there is few if any winter annuals germinating, even after 100 mm of rain in March. Sheep are currently grazing the paddock but will be rotated to a different paddock shortly.
Assessment: This paddock would make an ideal candidate for pasture cropping. Sowing a grazing cereal will allow grazing over winter with the option to lock up for grain. The paddock is also small enough that it can be effectively grazed. Nutrient levels may be low, particularly N and P, so a soil test would be advised. Considering the summer growth of the paddock, there may be low levels of stored soil moisture. Investigation with a soil push probe to determine available water for a winter cereal crop is also advised.
Example situation 2)
A 250 ha, long-term cropping paddock on heavy soil at Warren has only had one fallow spray after summer rainfall. There are some perennial summer grasses, mostly windmill grass and Feather Top Rhodes grass, with high densities of annual ryegrass and barley grass germinating at the moment. The farmer has very few livestock left after the drought.
Assessment: This paddock would make a poor pasture cropping candidate. Poor quality summer perennials mixed with high growth of winter annuals negate the benefits of pasture cropping with a dual purpose grazing crop. If finding it hard to source knockdown chemicals, the farmer may consider a strategic cultivation to remove summer perennials as well as kill germinating winter annuals. Alternatively, leaving paddock fallow with a knockdown spray when winter grasses flower in spring is another option.
Example situation 3)
A 15ha lucerne paddock along the river near Dunedoo has been affected by the drought and has failed to respond after recent rain. While the lucerne stand is good in patches, other areas have died off and the farmer is worried about large bare patches becoming weedy.
Assessment: An excellent candidate for “sod seeding” or pasture cropping. Lucerne should be grazed heavily before sowing with an application of paraquat/diquat to kill annual weeds before sowing. High N levels from the lucerne pasture, assuming adequate rhizobium nodulation, will result in high biomass production from a winter cereal meaning good grazing potential. If the season looks likely to cut out from lack of moisture, the high biomass production of the cereal coupled with the quality lucerne will make very good quality mixed hay. Winter cereal will also provide competition against weed encroachment. Establishment of the cereal in the areas thick with lucerne due to competition may be a problem and again, use soil push probes to determine available soil moisture.
It is important farmers are aware of the best situations to employ pasture cropping, as their situations may be different. Pasture cropping is an incredibly complex system with many factors to consider when making the decision to implement. I would advise doing your own research and talking to your trusted advisors before making any decisions. To learn more about pasture cropping and how it can fit into your enterprise mix please contact a member of our Ag Team.
References:
Badgery, W. (2009) ‘Primefact 875, Pasture Cropping’, NSW Department of Primary Industries
Badgery, B., Simmons, A., Murphy, B., Rawson, A., Lonergan, V. (2014) “The influence of land use and management on soil carbon levels for crop-pasture systems in Central New South Wales, Australia”, Agriculture, Ecosystems & Environment, Vol 196, pgs. 147-157
Dunn, J. (2012), Permaculture Research Institute, ‘Pasture Cropping: an Integrated Approach to Grain and Pasture Production’, accessed 1 April 2020, https://www.permaculturenews.org/2012/06/30/pasture-cropping-an-integrated-approach-to-grain-and-pasture-production/
Hoyle, F. (2013) ‘Managing Soil Organic Matter: A Practical Guide’, Grains Research and Development Corporation
Incitec Pivot Fertilisers (2018), ‘Nutrient removal after hay or grain harvesting’, accessed 1 April 2020, https://www.incitecpivotfertilisers.com.au/news-and-insights/agronomic-insights/winter-crop/nutrient-removal-after-hay-or-grain-harvesting
Leech, F. (2009) ‘Primefact 921, Cycling of phosphorous in grazing systems’, NSW Department of Primary Industries
Seis, C. (2012) ‘Winona’ – Farm Case Study: “Pasture Cropping, Profitable Regenerative Agriculture”, Innovations for Regenerative Landscape Management Project, Soils for Life