Italian ryegrass - More seed equals more feed

With sowing rates of Italian ryegrasses between the 15-30 kg/ha range, only now has work been done to measure whether this is economical for the farmer.

Many sources of information suggest that lower seed rates should be applied as it is cheaper for the farmer. However, research evaluating various sowing rates, now suggests Italian ryegrass sown at higher rates yields more drymatter and quicker- regardless of if it is sown in early or late autumn. These findings support a similar response to that of annual ryegrass, which trials have proven should be sown at 35-40 kg/ha to maximise profit in a pure stand scenario. See the next page for photographs of the 10, 30 and 60 kg/ha seeding rates at the first grazing.

Sowing rate Total yield  Changes in yield from lower rate Changes in costs Supplementary feed saved* Cumulative changes in profit*
kg/ha t/ha kg/ha $/ha $200 $200
 15 10.18  0 - - -
 20 10.45 270 $32 $54 $22
25 10.69 240 $32 $48 $38
30 10.91 220 $32 $44 $50
35 11.09 180 $32 $36 $54
40 11.24 150 $32 $30 $52
45 11.35 110 $32 $22 $42
50 11.44 90 $32 $18 $28
55 11.49 50 $32 $10 $6

*Based on supplementary feed value of $200/t

Example 1:
Producer increasing sowing rate from 15kg/ha to 35kg/ha.

Increase in yield: 270+240+220+180kg/ha = 910 kg/ha more. 
Cost in extra seed: extra 20kg x $6.40/kg = $128/ha more.
Value of extra feed: 910kg x $200/t bought in feed = $182
Return on Investment (ROI):
$182 - $128/ha = $54/ha improvement

Example 2:
Producer increasing sowing rate from 25kg/ha to 35kg/ha.

Increase in yield: 220 + 180kg/ha = 400 kg/ha more.
Cost in extra seed: extra 10kg x $6.40/kg = $64/ha more.
Value of extra feed: 400kg x $200/t bought in feed = $80
ROI: $80 - $64/ha = $16/ha improvement

Whilst yield can be increased beyond the economic optimums by sowing more seed, pursuing this yield is not effective as the effective price per seed is more than purchased supplementary feed, as shown by a decreasing profit in Table 1.

Based on this information we recommend producers sowing sole stands of Italian ryegrass move to a 35 kg/ha sowing rate.

We can see in Table 1 that this conservative recommendation would capture almost all additional profit for both producers, without pushing the system too close to the optimum and assuming too much risk.

For further information on how to get this to work on your farm for your particular cost of supplementary feed, contact your Stephen Pasture Seeds Pasture Specialist or your local agronomist.

Trials were sown in 2013 and 2014 and tested two diploid Italian ryegrasses’ Knight and Concord II, and, a tetraploid Italian ryegrass Feast II.

Results demonstrate sowing rates from 15 kg/ha to 55 kg/ha, total yield produced, the cost of increasing seed per ha and the cumulative change in profit from increasing sowing rate (Table 1 over page). The extra feed produced is based on the cost of having to buy in supplementary feed.

Increasing the sowing rate to 35 kg/ha provides the most return on investment (ROI) while maximising yield, particularly during autumn and winter.

By applying a cost to the extra feed produced we can understand which sowing rate is more economical. This work assumes that any extra feed grown reduces your supplementary feed requirements. It also assumes that if the seed costs less than the feed it grows- it makes good business sense.

Assumptions: Bought in supplementary feed value $200/t. Seed cost is $6.40/kg. Fertiliser and contractor costs remain the same for all sowing rates.

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