31 July 1998 Lucerne offers helping hand for drought-prone farmers – Lincoln scientist

A call for farmers to ‘rediscover’ lucerne as the best long-term forage crop on drought-prone properties comes from Lincoln University plant scientist Dr Derrick Moot.

Backing his call with experimental evidence, Dr Moot says that field trials he has conducted over the past two years clearly stamp lucerne as ‘king of the forages’ for dry matter yield compared with the more recently favoured red clover and chicory.

In a trial this year comparing the three species Dr Moot has achieved dry matter yields of 21 tonnes per hectare for lucerne against 16 and 17 tonnes respectively for red clover and chicory in a non-irrigated regime and 28 tonnes of lucerne against 21 and 20 tonnes for the other two under irrigation.

These very high yields were obtained on a deep Wakanui silt-loam soil at Lincoln University. On shallow soils with lower water-holding capacity, dry matter yields would be less, says Dr Moot, but the relative yield ratings of the three species would be the same for any site because of the greater water-use efficiency of the lucerne.

The superior yield of lucerne under dry land was obtained from the drought season rainfall of only 316mm between 1 September 1997 and 31 May 1998. This indicates that lucerne used each millimetre of rainfall more efficiently to produce dry matter than chicory or red clover.

Tying in his lucerne advocacy with the drought conditions experienced by farmers during the El Nino summer which has just passed, Dr Moot says the pattern over the past 12 months should be a lesson to all.

"Predictions are that Canterbury is likely to be drier in the future with less rainfall on fewer days," he says. "It's essential, therefore, that those farming land already prone to drought should start assessing their long-term feed options.

"While chicory might seem attractive as a 'quick fix' for dry seasons in terms of establishment speed, it certainly doesn't stack up against lucerne for dry matter production over the long term and, what's more, chicory doesn't fix nitrogen.

"With the availability of new cultivars which are resistant to many of the old lucerne pests, and with appropriate weed control and management practices, stands lasting seven years and more can be easily achieved. In contrast chicory stands might have a maximum persistence of only three to four years, particularly on heavier soils.

"Admittedly you have high establishment costs in terms of soil preparation (liming to ensure a pH of above 6.0) and weed control, but once the crop is under way, and with appropriate management, you can expect a longer and greater return for your effort than with red clover or chicory."

Explaining lucerne's fall from favour over the period since the 1980s, Dr Moot says issues of establishment cost, disease control, pests and a series of wet years when many Canterbury farmers 'forgot' they lived in what was really a drought prone area, all contributed to lucerne being shelved in favour of other sources of forage.

He says too that Wairau, the most widely used cultivar in New Zealand acquired a reputation as something of a ‘problem child’ in Canterbury during the late 1970s and early 1980s for its susceptibility to pests and diseases.

Today, through the work of plant breeders, resistance to many of the pests has been bred into the new generation of cultivars. Dr Moot used one of these in his trial, Grasslands' Kaituna.

It is appropriate that a call for revival should come from Lincoln University given that most of the early lucerne trial work was done there, with a whole generation of scientists, men such as Iversen, Stewart, Langer, Dunbier, Keoghan, and White making their name with the crop.

Many of the early trials were done on Lincoln's Ashley Dene Farm where today Manager Ken Townley has built an enviable production record with lucerne covering over 40 percent of the farm as his staple summer feed supply.

In promoting the advantages of lucerne for drought prone regions Dr Moot, who did his honours degree dissertation on the species back in 1986, says he is not coming up with anything new.

"My findings simply provide an opportunity to reconsider the situation.

"Furthermore, in addition to sheep, beef and deer farmers, perhaps some of the dairy farmers who in recent years have moved on to what for them must be climatically marginal Canterbury land need to look at lucerne.

"The system of incorporation needs to be investigated. Supplementary or break feeding lucerne could be the way to go in dairying operations.

"It has to be said that in Canterbury we haven't yet started to look at the place of lucerne in the dairy system. Traditionally dairying has been concentrated in the wetter areas in New Zealand where ryegrass/white clover thrives. However the limitations of this combination were evident this summer with farmers struggling to provide adequate irrigation water to maintain pasture production."

If any farmers are in doubt about the economic seriousness of the drought this past summer, they should heed the words of MAF policy analyst Chris Ward. It will cost farmers and orchardists $260 million this financial year, he says. And on-going losses and costs next year will add another $170 million to that – $50 million more than predicted.

North Canterbury Federated Farmers president Ross Little said the only realistic option for many drought-stricken farmers in his region had been to sell capital stock. "This has serious implications for the years ahead," he says.

Dr Moot says that as far as his call to reconsider the place of lucerne in Canterbury farming is concerned, it is significant that his figures come from a growing season in which Christchurch recorded its lowest eight-month spell of rainfall for 100 years. Just 21Omm of rainfall was recorded in the eight months from 1 September 1997.

"The first cut of the year for irrigated and dryland crops on the trial plots at Lincoln University, on 6 October, yielded 6.0 tonnes per hectare of 'Kaituna' lucerne; 5.1 t/ha of 'Pawera' red clover; and 2.4 t/ha of 'Puna' chicory. The need for a warm soil delays the spring production of chicory and the superiority of lucerne at this time is clearly evident," he says.

Ian Collins, Journalist, Lincoln University, Canterbury, New Zealand