With the correct management, lucerne can be a valuable high-quality spring and summer forage crop. To maximise crop yields and longevity, lucerne needs to be rested in autumn to allow root reserves to be replenished and in winter, weeds need to be controlled.
Lincoln University’s Professor Derrick Moot says farmers should set up their lucerne stands in June and July if they want to graze them in September.
He says winter is the time to be controlling weeds and recommends spraying grazed or mown stands with a mix of paraquat and residual herbicide at the recommended rates in June or early July.
Luisetti Seeds recommends ADAMA NZ’s paraquat FLASH® Herbicide and ATRANEX® WG Herbicide as the residual herbicide.
While FLASH has a knock-down effect and works on contact, ATRANEX WG has residual activity, which means it will stay in the soil and kill weed plants as they emerge in spring. ATRANEX WG is taken up through both the leaves and roots giving reliable long-term weed control.
If weed infestations are particularly bad, a repeat spray may be required in spring.
Without correct weed control, lucerne yields can be compromised by 20-40% and stand longevity reduced. With the correct management, lucerne stands should produce high quality feed for 10 years.
Derrick says after spraying, lucerne stands should not be grazed at all in winter, as grazing will hinder spring production.
While there may appear to be a green pick, these are the growing points on the plants and removing these will stop the plant from producing green leaf in the early spring period.
He says the plants have nodes that respond to air temperature. In temperatures above 5 degrees Celsius, the plant will produce a green leaf, which is held in compact form over winter.
In spring these leaves elongate and this is what provides the high-quality spring feed that makes lucerne such a valuable forage crop.
For more information about weed management in lucerne talk to your Luisetti Seeds agronomist.