Take Home Messages
- Standing cereal crops produce large volumes of feed, changing in feed value as they mature and set grain.
- Growing lambs grazing standing crops need a protein supplement, supplied either by legume grain, hay, or undersown medic or other legume pasture.
- Standing crop residues can be managed over summer to provide more groundcover than other pasture paddocks.
Background
A ‘standing crop’ is a cereal crop that has been held as a fodder bank for grazing later in the year once it has become reproductive, from late stem elongation and into grain fill. It can be used for high quality feed to lamb and wean lambs onto, and to finish lambs between three and six months of age. The standing crop can be a cereal, or a combination of a cereal with a legume or grain supplement which delivers higher protein for growing lambs.
The practice is low cost and low risk. The standing crop is sown and grown as a crop would be for harvest, ie. locally adapted varieties are sown on time with adequate fertiliser and weed management to maximise dry matter production, as opposed to just ‘banging something in’ with little or no management. The crop is assessed in late winter or early spring for its best end-use opportunity. Responsive decisions are made to graze, cut for hay or harvest the crop, based on lamb and grain commodity prices, and seasonal conditions or events such as heat stress or frost that might cause a grain crop to fail.
Grazing of senesced pastures and stubble residues during dry months will eventually expose soil to the elements, increasing the risk of erosion from summer storm events. Because a full standing crop offers greater biomass, and grain in the head can meet the higher nutritional demands of lamb production (with a protein supplement), lambs will reach sale weight faster and can be removed from the property sooner. This relieves stocking rate pressure over summer months, preserving groundcover levels and reducing the risk of overgrazing and exposing soils.
Aim
To demonstrate the production of a range of cereal varieties and their grazing value, and the effect of sowing rate and fertiliser for growing standing crops.
To demonstrate the performance of new medic releases.
Paddock Details
Location: Nullawil
Crop year rainfall (Nov–Oct): 497mm (decile 10)
GSR (Apr–Oct): 384mm (decile 10)
Soil type: Sandy clay
Paddock history: Lentils
Trial Details
Crop type/s: Barley, oats, triticale, ryecorn, medic
Treatments: Refer to Table 1
Seeding equipment: Knife points, press wheels, 30cm row spacing
Sowing date: 25 May 2022
Harvest date: 9 December 2022
Trial Inputs
Fertiliser: Granulock® Supreme Z + Flutriafol (200mL/100 kg) @ 60kg/ha at sowing
Trial managed as per best practice for herbicides, insecticides and fungicides.
Method
Single plots of cereal varieties were sown as a demonstration. Assessments included peak biomass and grain yield. Feed tests were conducted on biomass samples, and grain protein measured in grain.
Results & Interpretation
Measured in March, plant available water was 91mm and soil N to 1m was 80kg N/ha.
The 2022 growing season at Nullawil began after 39mm rain in the second half of April, although little rain fell in the three weeks before sowing. Trials established evenly, but became moisture limited on the clay soil during winter, stressing leaf tips. For four months, rainfall was recorded on three out of every four days, but there were only eight rain events that exceeded 4mm. From 8 September, conditions turned around, becoming very wet. Crops recovered well with the spring rain and the growing season improved to a decile 10.
Biomass value
Peak biomass sampled on 17 October as cereal crops finished flowering/early grain fill, measured 7.0–11.7t/ha (Table 1). Single plots of oat varieties essentially grew 10t/ha biomass, barley 8t/ha, and triticale and ryecorn 9t/ha.
Forage varieties Overland and Marleigh oats, and long season Forester oats were still testing >12% for protein, as did forage barley Kraken and grain types Spartacus CL, Commodus and Maximus.
Many varieties of oats and barley were still testing >8MJ ME/kg DM after flowering — useful levels of energy for maintenance of dry ewes but not for production feeding.
However, acid detergent fibre (ADF) and neutral detergent fibre (NDF) levels were increasing, affecting how much a sheep could consume at this point. High quality hay targets are ADF <30–32 per cent and NDF <55 per cent. Again, fibre was useful for maintenance feeding but not production.
Grain value
By December, grain was mature and offering 2.5–5t/ha for forage oats and 4.3–5.5t/ha for grain type oats, and 3.4t/ha for forage barley and 5.0–6.4t/ha for grain type barleys.
Feed tests hadn’t been done on the grain at the time of writing, but BCG lab NIR grain protein measured 8.7–11.2 per cent in oats and 9.2–13.1 per cent in barley. Bilby and Kingbale oats, and most barley varieties measured >10 per cent protein.
Sowing rate effect
Wintaroo was sown at two sowing rates to see if there was an effect on biomass or grain production and quality. In terms of biomass, the oats were able to compensate for lower plant densities (as seen in the oaten hay trials at the same site) and had similar quality (Table 1).
Grain yield and grain protein were higher for the lower sowing rate of 60kg/ha but caution must be taken as plots were not replicated.
Fertiliser effect
The last run of plots sown repeated the same varieties as the previous run, but with no fertiliser. There appears to be a strong fertiliser response to biomass production and protein, and to grain yield and grain protein (Table 2).
Potential to undersow with medic
As standing crops mature through head emergence and through early grain fill, protein dips and is not enough to support lactating ewes or growing lambs. To meet the protein shortfall, a highly digestible legume can be undersown with the cereal crop. Medic, clover, vetch, lucerne or serradella are suitable for satisfying that role, depending on soil type.
Single plots of pure medic varieties were sown to see how the new medic varieties Seraph, Emperor and Penfield performed against older varieties Parragio and Parabinga.
By 17 October, biomass cuts measured large amounts of feed, highest for new release varieties Emperor and Penfield with plots yielding towards 6t/ha, and early Seraph and older variety Parabinga towards 5t/ha (Table 3).
Feed tests for medic still showed high quality at this time of year, while other cereals were beginning grain fill. Crude protein was very high around 20 per cent, ME about 10MJ ME/kg DM and fibre levels were of good quality for forage (Table 3).
The establishing medic also responded to fertiliser at sowing, producing 0.5t/ha more biomass and similar quality than the unfertilised plot, by 17 October (Table 4).
Groundcover
Groundcover from the different cereal crops and pastures in all plots was 100 per cent in October, covering plots with varying amounts of biomass and composition of plant material. Breakdown rates of crop and pasture residues are enhanced by nitrogen content, and contact with the soil, so cereal residues generally take longer to break down than legume residues. Depending on when and how standing crops are grazed, the volumes of biomass show great potential for providing greater groundcover over summer months, when other pastures have senesced or have been chemically fallowed.
Commercial practice and on-farm profitability
The demonstration supports previous work showing several oat and barley varieties, both forage and grain types, can provide useful feed for supporting livestock at different times of the year Best varieties are those you already have on hand, or choose one that is fit for purpose.
Feed tests will measure exactly what your crop is providing at the time, but in general:
- Young cereal crops at GS30 have about 1.5t/ha biomass, and high protein (20–30 per cent), energy (12–14 MJ/kg), lower NDF (35–45 per cent) and high digestibility (>80 per cent)
- By flowering GS65, crop biomass can range from 4–12t/ha, but quality falls to maintenance levels (hay quality) with lower protein (8–9.5 per cent) and energy (8–9.5 MJ/kg), higher NDF (55–70 per cent) and lower digestibility (50–60 per cent).
- Once grain has set, feed value rises again. The best feed value is the grain component, and to a lesser extent leaves and fine chaff. Grain has very good protein (11–15 per cent) and energy (12–14 MJ/kg), low NDF (10–30 per cent) and high digestibility (70–95 per cent). Of course, fibre will be consumed in chaff and leaves as sheep eat the crop, so fibre needs will be met.
During the spring period when crops flower and enter grain fill, quality falls and limits how much livestock can consume. During this time supplementing with another source of protein and energy may be needed to meet any nutritional shortfalls. The crop will have enough nutrition to support dry ewes, but it can’t support the needs of growing lambs.
If livestock have already been on a large paddock for some time, they might have grazed parts of the paddock harder than others. Crops growing back on these patches will have fresher, more nutritious feed, and the supplement may not be needed yet, but it depends on the size of the areas and number of stock on the paddock.
Once grain has matured, lambs will grow successfully again, particularly on a diet supplemented with undersown legume pasture, a legume grain feeder or access to an adjacent paddock with legume stubble to top up their high protein and energy needs.
Steps for managing sheep on standing crops and onto grain, and how you might manage a standing crop paddock in a rotation, are outlined in the ‘Value of standing crops for lamb production and soil protection article’ in the 2019 BCG Season Research Results.
Consider setting up a standing cereal crop that allows flexible options for its use across the growing season, supports livestock production with the right management, and provides groundcover into the summer months, protecting soils and supporting soil health.
References
Frischke A., and Jolly S., 2020, 2019 BCG Season Research Results, ‘Value of standing crops for lamb production and soil protection’ pp. 162–168.
Acknowledgements
This project is funded by the Australian Government’s National Landcare Program and delivered by BCG and MacKillop Farm Management Group (MFMG).
Special thanks to Millie Moore of S&W Seed Company and Craig Altmann of AGF Seeds for providing seed for the trial.
