IN006: Using grazing cereals and
perennials in the high rainfall zone to
increase farm productivity while
improving soil and plant diversity.
2015 Technical Report
Manjimup Pasture Group
Background & Aims:
Establishing grazing cereals and perennial pastures in one grazing system in the high rainfall
zone is an innovative means of increasing productivity whilst protecting soils and increasing
groundcover and biodiversity. The ability to graze specialty grain crops and increase winter
feed availability for livestock enterprises while providing the opportunity to produce fodder
and grain crops at the end of spring is being realised and adopted in the medium and low
rainfall regions of WA. It is designed as a low input system (producing two crops for the
value of one) while increasing productivity and maintaining (or even improving) the
sustainability of the whole pasture system. However, little work has been done with this
technology (nor incorporating perennials with it) in the high rainfall zone of the south west.
The aims of the Manjimup Pasture Group trial are to:
1. Demonstrate and evaluate effective techniques for establishing grazing crops and
perennial pastures in the high rainfall zone. Specifically, this project will compare techniques
in the Manjimup area by measuring grain yields and biomass production.
2. Increase the green feed availability of pastures by one month at the beginning and end of
the normal (May to October) growing season. This will be demonstrated by comparing crop
vigour with GreenSeeker®crop sensing system between treatments and control plots in April
and November.
3. Demonstrate and evaluate the productivity and profitability of the grazing crop system
through enterprise gross margin analysis (returns less direct operating costs). Analysis of
cereals will be based on yields and grain price to determine returns, and pastures will use
biomass production converted to DSE (dry sheep equivalent) grazing days.
4. Improve knowledge and skills of at least 15 farmers and 15 students relating to the
economic and environmental benefits of establishment techniques of grazing crops and
perennial pastures.
Methods:
The trial site is located near Manjimup in the high rainfall zone of the south west of WA.
The trial site receives an average annual rainfall of 800mm and has fertile gravelly loams as the
major soil type. Pre-trial soil tests showed that there were no soil constraints that would be likely to
limit productivity.
The trial site is 2.2 ha in size with 6 treatments sown in 100m long strips. There are 2 replicates of
each treatment giving a total of 12 plots.
The trial is comparing six different methods of establishing perennial pastures:
1. Shallow sown perennials (Control) – no seed treatment - no cereal.
2. Skip row sowing: deep cereal / shallow perennial sown 6 inches apart
3. Same row sowing: deep cereal / shallow perennial (both sown at ideal depth with a tine
machine and press wheel. Seed boot tied to the back of the tine to drop perennial seed in
front of the press wheel – done simply by using a Duncan drill and cable ties)
4. Same row sowing: Shallow cereals and perennials (a common option when sowing
perennials with a cover crop is to sow all species at a shallow depth for perennials. This
normally disadvantages the cereal which will generally yield less than deep sown cereals.)
5. Shallow sown perennials + seed treatment (mycorrhiza and nutrient seed treatments) – no
cereal
6. Same row sowing - deep cereal / shallow perennial (minus Lucerne in perennial Mix),
because some people in the group don’t think we can get productivity of our Lucerne.
Treatment 5 was separated from the other treatments by a wide buffer strip to avoid any ‘edgeeffects’ of the biological seed treatment on neighbouring plots.
See trial layout below.
The grazing cereal we have sown in the trial is Einstein wheat applied at 90kg/ha, and the perennials are Phalaris (Advanced AT – 2kgs/ha), Chicory
(Commander - 1 kg/ha), and Lucerne (SARDI 7 Series II – 2kgs/ha). Over the past 6-7years these three species have probably been the best performing
perennials outside of Kikuyu in this area. The cost of establishment was about $150/ha (including cereal and perennial seed, fertiliser and application). See
interim gross margin analysis in the results section for further details.
The site had two cultivations and a knock down and was sown on the 25th of June 2014 with 40kg/ha of Agras as an upfront fertiliser. The first graze was
planned in August but the perennials in the “no wheat” treatments weren’t established sufficiently for this to occur. If we had have grazed we probably
would have had shorter cereals and the perennials starting to take over.
Soil tests were taken at depths of 0-10cm and 10-20cm from each of the 6 treatments prior to
sowing (May 2014) and again in January 2015. 10 sub-samples were taken from each plot and bulked
prior to analysis by CSBP Kwinana Soil & Plant Analysis Laboratories.
The site has been grazed once in March 2015, with 148 ewes (1 DSE) put in the trial paddock on the
3rd of March and taken out on the 24th March (21 days). The paddock in which the trial is located has
a total area of 8ha, and the trial itself is 2.2ha (unfenced), giving a total of 855 grazing days on the
trial area assuming that the paddock was grazed evenly.
A Greenseeker is a hand-held optical tool used to measure the ‘greenness’ of a pasture or crop,
which gives a relative indication of living biomass. Greenseeker transects have been conducted once
on each plot, in January 2015 (post-harvest). Transects were completed by walking at an even pace
along the length of each plot while holding the Greenseeker at a height of 1m above the ground.
Stationary Greenseeker measurements were also taken above each 25x25cm quadrant prior to
collecting biomass samples.
Biomass cuts have also been collected twice on each plot, in October 2014 and January 2015.
Different methods were used on each occasion. In October, cuts were taken from two 1mx1m areas
in each plot (northern & southern end) using a lawn mower set to a height of 3cm. Crop and pasture
biomass were not separated but dried and weighed together to determine Total Dry Matter (TDM).
In January biomass cuts were taken immediately post-harvest, meaning that there was green
perennial biomass in amongst dry, 20cm high cereal stubbles. A 25x25cm quadrant was thrown
randomly into the crop/pasture at the southern and northern ends of each plot. Cuts were not taken
from within the grazing cages (as per previous cuts) because no grazing had been conducted on the
site. Pasture growth outside of the cages represented full-season production, and was not impacted
by the October cuts which appeared to stunt the cereal growth being so late in the season. In
January only perennial biomass was collected for drying & weighing (not cereal stubbles). All
samples were collected in labelled paper bags and sent to the Manjimup Department of Agriculture
for wet and dry weights, and then converted to TDM per hectare.
Pasture density was determined on each plot in January 2015 (post-harvest). The number of
individual plants of each pasture species within the 25x25cm quadrats was used to determine plants
per square meter. Prior to this time, perennial density would have been difficult to measure given
the similarity between a phalaris and wheat seedling.
Gross margin was calculated for each treatment using a Planfarm Gross Margin Spreadsheet. Grazing
value was determined using a value of $150 per tonne of perennial pasture TDM measured in
January (end of production year). This method was used in preference to actual grazing days
because the site was grazed as a whole, not as individual treatments and so differences in biomass
production could not have been differentiated. Wheat revenue was set at $265 per tonne, which
was the actual on-farm price received. All other costs were based on actual expenditure, including
contract rates for weed and pest control, seeding and harvest.
Results & Discussion:
The results from the October biomass sampling showed that there was significantly higher TDM
within the treatments that had cereal compared to the perennial-only treatments. This was to be
expected given that cereals (being an annual) put on significant bulk early, while perennial pastures
are slow to establish with low biomass production in the first year. However there was no significant
difference between any of the four wheat treatments, nor between the two no-wheat treatments.
Graph 1: Perennial & cereal dry matter production in October 2014
Total Dry Matter Production (cereal + perennial pasture) in
October 2014
4000
Total Dry Matter (kg/ha)
3500
3000
2500
2000
1500
1000
500
0
Shallow sow:
treated
perennials (no
wheat)
Shallow sow:
untreated
perennials (no
wheat)
Skip row: deep Same row: deep
Same row:
Same row: deep
cereal, shallow cereal, shallow shallow cereal & cereal, shallow
perennial
perennial
perennial
perennial (no
lucerne)
The results from the January sampling revealed several trends. Firstly that perennial dry matter
production is tied to plant density. However this relationship is not convincing, as evidenced by the
nearly 6-fold difference in dry matter production between the ‘Untreated perennials’ and the ‘Skip
row’ treatments, with only a 25% difference in plant density. It appears as though the main impact
of the cereal crop in treatments 2 and 4 (Skip row; Shallow cereals & perennials) has been to stunt
the growth of the perennial seedlings (through competition), rather than inhibit perennial
establishment. This is a positive finding, as these two treatments were intended to reduce the
competitiveness of the cereal crop, and with a higher plant density there is a greater chance of the
perennials persisting into years 2 and 3. Treatments 1 and 6 (Treated perennials; Deep cereals &
shallow perennials – no Lucerne) are significant outliers in terms of both TDM and perennial plant
density, and at this stage it is unclear what has caused this result.
Graph 2: Perennial Dry Matter and Plant Density in January 2015
2500
80
70
2000
60
50
1500
40
1000
30
20
500
10
0
Plant count (perennials/m2)
Perennial Pasture Dry Matter (kg/ha)
Perennial Dry Matter & Plant density of MPG Pasture
Establishment Trial
Manjimup January 2015
0
Shallow sow: Shallow sow: Skip row:
treated
untreated deep cereal,
perennials
perennials
shallow
(no wheat) (no wheat)
perennial
Dry matter
Same row:
shallow
cereal &
perennial
Same row: Same row:
deep cereal, deep cereal,
shallow
shallow
perennial perennial (no
lucerne)
Plant Density
The second trend to be identified was that the Greenseeker index approximately matched the
perennial dry matter (Graph 2), with the only exception being a reversal of results from the two
perennial-only treatments. The accuracy of the GS may have been compromised by the high
biomass, upright form and reproductive stage (browning-off) of the perennials in those plots.
Graph 2: Perennial Dry Matter and Greenseeker readings
3000
0.3
2500
0.25
2000
0.2
1500
0.15
1000
0.1
500
0.05
0
0
Shallow sow: Shallow sow: Skip row:
treated
untreated deep cereal,
perennials perennials
shallow
(no wheat) (no wheat)
perennial
Dry Matter
Same row:
shallow
cereal &
perennial
Same row: Same row:
deep cereal, deep cereal,
shallow
shallow
perennial perennial (no
lucerne)
Greenseeker
Greenseeker Index
Perennial Pasture Dry Matter (kg/ha)
Perennial Dry Matter & Greenseeker Readings of MPG
Pasture Establishment Trial
Manjimup January 2015
The third and most significant trend shows that the higher the wheat grain yield, the lower the
perennial dry matter production. In other words, there has been a significant effect of establishing
wheat (at high sowing rates) on perennial productivity in the first year. The results that have the
highest statistical significance are the perennial biomass production of the two non-wheat
treatments vs all twin-sown treatments, and treatment 6 (Same row: deep cereal, shallow perennial
(no lucerne)), which had significantly higher wheat yield but lower perennial dry matter and plant
density than the other twin-sown treatments.
Graph 3: Perennial Dry Matter and Wheat Yield
3000
4.5
4
2500
3.5
2000
3
2.5
1500
2
1000
1.5
1
500
Wheat Yield (tonnes/ha)
Perennial Pasture Dry Matter (kg/ha)
Perennial Dry Matter & Wheat Yield of MPG Pasture
Establishment Trial
Manjimup January 2015
0.5
0
0
Shallow sow: Shallow sow: Skip row:
treated
untreated deep cereal,
perennials perennials
shallow
(no wheat) (no wheat)
perennial
Dry matter
Same row:
shallow
cereal &
perennial
Same row: Same row:
deep cereal, deep cereal,
shallow
shallow
perennial perennial (no
lucerne)
Grain Yield
Gross margins (GM) were calculated for the first year across all treatments. As mentioned
previously, grazing value was determined by allocating a value of $150 per tonne of perennial
pasture TDM. In this comparison no grazing value was attributed to either the immature crop or the
cereal stubbles. This analysis showed that GM was highly dependent on crop yield, as this was the
main income source. Although the variable costs of establishing the perennial-only treatments ($257
/ ha) were less than that of the twin-sown treatments ($360-380 / ha), this difference was more than
accounted for by the income generated from grain sales ($818-$1049 / ha). Grazing value was
relatively small compared to grain value, even where TDM exceeded 2 tonnes per hectare. The
highest gross margin was derived from treatment 6 (Deep cereals & shallow perennials, no Lucerne)
at $695 / ha, and the lowest gross margin was derived from treatment 1 (untreated perennials) at $44 / ha. With this in mind, the grazing value of perennial pastures will continue to increase in years
2 and 3 with minimal additional costs, while there will be no additional income from the cereals
unless they are re-sown. It will be interesting to revisit this GM analysis in one and two years’ time
once the full value of the pastures have been realised.
First Year Gross Margins of Perennial Pasture Establishment
Techniques in Manjimup, W.A.
$1,200
$1,000
$800
$695
$600
$509
$476
$400
$571
$200
$99
$0
-$44
-$200
-$400
-$600
Shallow sow:
untreated
perennials (no
wheat)
Shallow sow:
treated
perennials (no
wheat)
Skip row: deep
cereal, shallow
perennial
Total Income
Same row:
Same row: deep Same row: deep
shallow cereal & cereal, shallow cereal, shallow
perennial
perennial
perennial (no
lucerne)
Total Variable Costs
Gross Margin
Conclusion:
The results of this trial to date show that:





There is a trade-off between cereal crop productivity and perennial pasture productivity.
Twin-sowing establishment techniques that limit the competitiveness of the cereals (i.e.
skip-row sowing and shallow sowing of cereals) have effectively the same perennial plant
density as the perennial-only treatments, but significantly lower biomass production.
Sowing perennials by themselves (i.e. no cover crop) is the best way to ensure
establishment success and biomass production in the first year.
Twin-sowing generates a significant increase in gross margin through grain sales in year one.
The presence of Lucerne appears to have increased perennial biomass and plant density in
year one, as evidenced by significant differences between the ‘no Lucerne’ treatments (#6)
and all other plots. However the mechanism by which this happened is not yet clear and
needs to be investigated further.
After reviewing the results from year one, MPG members have identified several questions that they
hope will be answered throughout the remainder of this trial:


If you are sacrificing plant density and biomass production of perennials in the first year to
gain income from the cash crop, what is the longer-term cost/benefit?
Are you better off to sow the cereal crop in year one, gain the benefits of increased income
and weed control, and then sow the perennial pastures in year two?


Will the twin-sown perennials persist in years 2 and 3 or is the plant density too low?
How does a change in timing of the seasonal break affect the optimum sowing strategy?
This project is supported by South West Catchments Council through funding from the Australian
Government's National Landcare Program and members of the Manjimup Pasture Group.