Last summer irrigated fodder crops, primarily millet, were used to boost summer production but with the ultimate aim to clean up paddocks to sow a perennial ryegrass. This proved very successful with some fantastic perennial ryegrass swards.
Irrigating fodder crops in some cases can be quite profitable, however being able to utilise the feed as it arrives and hence maintaining feed quality is the key to get a return on the higher input cost the fodder crops require. The split calving pattern (leaning on the autumn calving side) on the focus farm means the demand for feed in the middle of summer is not high and the fodder crop will be difficult to control. With this in mind the plan is to irrigate existing perennial and Italian ryegrass paddocks until the autumn calvers begin to be dried off, and then start up at the end of summer. This will provide a low input cost system with flexibility and ability to adapt.
Normally to maximise pasture growth and water-use efficiency it would be best to continue irrigation though the summer once started, however this is only the case if the feed grown can be utilised and grazed to maintain quality. In this instance cow numbers in mid to late summer will be low and the irrigated pasture will provide a good base to the diet, but peak milker numbers will be in late May and June. There is little point sowing a summer crop that will be grazed for only a few weeks through January, especially with relatively low cost home grown silage on hand. The six or so weeks of no irrigation will be used to clean up some paddocks and undertake some drainage work ready for the autumn start irrigation. It is expected the selected areas will be sprayed out in January and then grazed with dry cows to reduce trash issues for sowing. If possible the paddocks will be pre watered and sprayed once again to eliminate summer weeds. Sowing is likely to be early March to provide feed for the peak demand late in April. The aim is to have all paddocks in the milking rotation by then, at the best quality possible.
A paddock (10 ha) which is rarely grazed with milking cows has been sown down to dryland lucerne, with excellent preparation, seed bed, germination and sub-soil moisture. It will be interesting to see the long term results (the last bit of rain has been handy). Sown in the first week of October it is expected it will be ready to graze by Christmas. With some good luck and planning, the area will now provide late spring and autumn growth with the flexibility to be grazed if required, or cut as quality hay or silage if available feed is surplus to requirements.