Mungbeans join sugarcane in tropical rotations

Queensland mungbean crops expand into coastal areas

Legumes & Pulses
Mungbeans are being grown in rotation with sugarcane in some regions of Queensland, including the Burdekin. PHOTO Cindy Benjamin

Mungbeans are being grown in rotation with sugarcane in some regions of Queensland, including the Burdekin. PHOTO Cindy Benjamin

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Legume cash crop rides wave of success as growers seek to diversify farming systems.

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Mungbeans are working their way into rotation with sugarcane in the Burdekin, Queensland, as a profitable cash crop that also delivers soil health improvements and often a yield benefit in following sugarcane crops.

Fast growers

While the current annual mungbean area in the Burdekin is small at about 3000 hectares, Australian Mungbean Association (AMA) president Mark Schmidt says grower and adviser interest in the crop is on the rise.

Over the past few years, growers have seen the immediate benefit of putting in mungbeans and soybeans, and mungbeans are the faster-growing and more profitable crop, Mr Schmidt says.

Along with the AMAs extension work, GRDC-invested projects with partners such as CSIRO and the Queensland Department of Agriculture and Fisheries are helping growers make informed decisions about when and how to grow mungbeans in the dry tropics as well as coastal and established inland areas.

Over the past few years, growers have seen the immediate benefit of putting in mungbeans and soybeans, and mungbeans are the faster-growing and more profitable crop - Australian Mungbean Association president Mark Schmidt

Dual window

The Burdekins main mungbean crop is planted in August and harvested in November-December, and its secondary crop is planted in early February for harvest in April-May.

If old sugarcane is removed in winter, back-to-back break crops - including mungbeans - can be grown prior to the planting of new sugarcane in the following autumn.

Sugarcane will remain the main crop for the region, but as growers look to diversify to improve soil health and make more money out of the rotation, mungbeans can be a profitable option, Mr Schmidt says.

He says mungbeans require close attention during their short growing season to maximise yield potential, which has a regional average of about two tonnes per hectare.

Critical management times for mungbeans are at flowering and podding, when insect damage can affect yield, and at maturity.

This is when picking the right time for defoliation can be difficult because mungbean crops in the dry tropics will continue to flower, even when early pods are fully mature.

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CSIRO researcher Dr Stephen Yeates has a long association with mungbeans in tropical agriculture, and is currently working on a GRDC-invested Grower Solutions Project to help growers in coastal and hinterland areas - including the Burdekin - to develop optimal management practices and identify varieties best suited to the region.

Yield is generated in the last 30 days, so the timing of management decisions is critical. - CSIRO researcher Dr Stephen Yeates

To make the most of this crop, we have been investigating the basic agronomic parameters, such as sowing dates, row width and irrigation timing, that generate the most reliable and high-quality results from the current and upcoming varieties, Dr Yeates says.

Yield is generated in the last 30 days, so the timing of management decisions is critical.

Water-efficient

Mungbeans are highly water efficient, with irrigated crops requiring about 3 megalitres per hectare, compared with 14ML/ha for sugarcane, and produce less trash than alternative break crops such as rice and maize.

Warm temperatures and low humidity allows the pods to ripen in just 10 days, so the timing of the last irrigation is very important, Dr Yeates says.

CSIRO researcher Dr Stephen Yeates examines a mungbean crop in the Burdekin. PHOTO Cindy Benjamin

CSIRO researcher Dr Stephen Yeates examines a mungbean crop in the Burdekin. PHOTO Cindy Benjamin

A drying soil stimulates the plant to start its desiccation process, and a late irrigation or rainfall event can create harvest difficulties through high plant-moisture content.

Mungbeans in Queenslands sugarcane areas are often irrigated and usually require a pre-sowing watering and at least another at flowering.

Mungbeans flower within 45 days, and are mature in 80 days from planting, so their fast growth habit means they can sometimes be grown as dryland crops.

While varieties currently available are well-suited to the Burdekin, Dr Yeates believes the regions climate will support varieties that produce many more flowers than set by current varieties.

Well-drained soils in the Burdekin can yield up to 2.5t/ha of mungbeans and Dr Yeates sees potential to increase this through fine-tuning the agronomy and removing the genetic constraint to the number of flowers per plant.

The second flush of flowers comes about 21 days after the first, potentially adding 30 to 40 per cent in yield, or rescuing a crop if the first flush is weathered," he says.

However, waiting for the second flush extends the growing period and it would usually be better to have more flowers on the first flush and to harvest at the earliest opportunity.

National angle

Dr Yeates is working in partnership with the National Mungbean Improvement Program to screen new varieties for their suitability to the dry tropics.

At the Burdekin, we have demonstrated sowing at the optimal times of mid-August to early September and late January to February is best to avoid rain at maturity, while maximising yield," he says.

Maintaining good prices and high quality will also be essential to sustaining mungbean in the region as other crops, such as soybean and rice, become better options for growers when mungbean returns are lower.

In response to the increased interest, the AMA ran a two-day Mungbean Best Practice Management Agronomy and Accreditation course for growers and advisers for the first time in the Burdekin in December 2017.

The course gives new growers and agronomists more confidence in their decisions. - Australian Mungbean Association president Mark Schmidt

We had more than 30 agronomists come along to the course and if you consider that each of these agronomists works with four or five existing or potential growers, thats a big reach, Mr Schmidt says.

We run these courses in all mungbean-growing areas every few years so that growers and advisers have a good idea about how to grow the best-possible mungbean crop.

The course gives new growers and agronomists more confidence in their decisions.

It is also a great refresher for the more experienced players.

Further interest

Mr Schmidt says mungbeans are attracting attention from sugarcane growers in other coastal Queensland regions, including Mackay and Proserpine.

This is for their potential to help manage grass weeds, provide a nitrogen boost and rebalance soil fungal communities.

While one facility processes mungbeans in the Burdekin, for containerised export through Townsville, Queensland, Mr Schmidt says much of the regions production is trucked to Biloela, or the Darling Downs, for packing into containers for export out of Brisbane.

Australias largest-ever mungbean crop of 180,000t was grown in 2015-16.

More information: Mark Schmidt, 0477 304 241, mds19@bigpond.com

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