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Agronomic and economic potential of grain legumes in Tasmania

G J Dean1 and N J Mendham2

Tasmanian Institute of Agricultural Research
1
Mt Pleasant Laboratories, Launceston, Tasmania
2
University of Tasmania, Hobart, Tasmania

ABSTRACT

Field trials were conducted in 1998/99 and 1999/00 to evaluate the performance of a range of grain legume crops. Average yields varied significantly, from 0.1 t/ha for frost-damaged chickpeas through to over 5 t/ha from faba beans. In Tasmania relatively high costs of production mean it is critical to focus on import replacement and/or high value crops. There is also a need to capitalise on environmental and cultural advantages. In particular a mild finish to the growing season and capacity to irrigate assist in producing large seed sizes which are associated with price premiums for bitter albus lupins, green lentils, chickpeas, maple peas and marrowfat peas. These and other grain legume options are discussed in relation to crop suitability for 3 broad climatic cropping zones in Tasmania.

KEY WORDS

Grain legumes, pulses, evaluation, Tasmania.

INTRODUCTION

As in many areas of Australia dryland farmers in Tasmania are struggling to develop economically viable and environmentally sustainable crop rotations. Cereals are an established core of the rotation along with alkaloid poppies that have recently expanded in area. The canola industry in Tasmania is in its infancy and will be restricted in many areas by adjacent brassica seed crops. Grain legumes/pulses, in addition to providing disease and weed breaks, can also be important in providing nitrogen for the following crop.

This paper discusses the performance and potential of grain legume crops trialed over two seasons in Tasmania.

METHOD

Trials were conducted over the 1998/99 and 1999/00 seasons at 9 sites throughout the main cropping areas of Tasmania. Trial sites were categorised into three broad zones based on the major environmental and cultural limitations:

Zone 1. Central and Southern Midlands. This area is characterised by a relatively harsh and cold environment (July mean maximum of 10C) with frosts often occurring as late as mid November. Annual rainfall is about 500mm with hot and dry conditions in late spring and summer generally limiting the success of later plantings.

Zone 2. Northern Midlands. Most of the cropping in the Northern Midlands occurs on duplex soils that commonly suffer from winter waterlogging. Late frosts can be damaging although they are generally less severe than those in Zone 1. With an annual rainfall of around 600mm, spring-sown crops are an option although dry spring periods often restrict yield. Production of crops on raised beds has been widely adopted as a means of avoiding waterlogging.

Zone 3. Higher rainfall/irrigated vegetable growing areas. This zone centres on the North West Coast with well-drained and highly fertile basalt-derived soils. The generally mild coastal conditions and high rainfall (800-1000 mm) also result in increased disease pressure, particularly in early sown crops. The major limitation to grain legume production in this area is competition from other high returning crop options. Farmers will only consider pulse crops with good returns.

Seven grain legume species were evaluated: narrow leaf lupin (Lupinus angustifolius), albus lupin (L. albus), yellow lupin (L. luteus), faba bean (Vicia faba), field pea (Pisum sativum), lentil (Lens culinaris) and chickpea (Cicer arietinum). Previous work by Charleston (1) suggested that lentils and chickpeas were the only viable options for Zone 3.

Generally a minimum of five cultivars of each crop were grown at each site although evaluations of up to 24 varieties of potentially more suitable species were trialed at some sites. There were 3 replicates of plots that were 8 rows wide and 10-15m long. Sowing dates varied depending on species and zone limitations (Table 1). Some species were sown in both autumn and winter/spring to determine optimum sowing time.

Table 1. Crop type and trial sowing dates in each cropping zone.

Crop

Zone 1

Zone 2

Zone 3

Lupins

end April-mid May

early-mid May

-

Faba beans

end April-mid May

early-mid May

-

Lentils

mid-late May

early-mid May
end Aug-end Sept


mid Aug-mid Sept

Chickpeas

mid May

mid May
end Aug-end Sept


mid Aug-mid Sept

Field peas

mid May
early Aug

mid May
end Aug-end Sept

-
-

Target plant densities varied with crop type. A range of pre-emergent and post-emergent herbicides was used and insecticides and fungicides were applied as necessary. Harvest dates ranged from the end of December for faba beans in Zones 1 and 2 to late February for spring-sown chickpeas in Zone 3.

RESULTS

Crop yield data for each of the climatic zones are presented in Table 2. Further details on cultivar and site yields are available from the authors. There was a large variation in yield across the zones with severe late frosts at the end of October and mid-November and a colder and drier climate affecting yields in Zone 1. Of the species evaluated, faba beans showed the best adaptation with the highest yields in zones 1 and 2. Narrow leaf and albus lupin yields were variable with relatively low yields in Zone 1. Lentils showed yield stability across environments with highest yields obtained in Zone 3.

Table 2. Grain yields for each crop type in the 3 major cropping zones of Tasmania (means of 1998/99 and 1999/00).

 

Grain Yield

Crop

Zone 1

Zone 2

Zone 3

 

Mean yield (t/ha)

Standard deviation (t/ha)

Mean yield (t/ha)

Standard deviation (t/ha)

Mean yield (t/ha)

Standard deviation (t/ha)

Faba beans

2.1

0.9

5.4

0.9

-

-

Narrow leaf lupins

0.7

0.2

3.4

0.9

-

-

Albus lupins

0.9

0.4

3.5

0.6

-

-

Yellow lupins

0.6

0.4

2.5

0.4

-

-

Field peas

1.5

0.2

2.1

0.4

-

-

Lentils

1.1

0.3

1.7

0.8

2.7

0.8

Chickpeas

0.1

0.1

1.1

0.2

1.2

0.4

The growing seasons in 1998/99 and 1999/00 were characterised by below average winter rainfall with late opening rains in 1998/99. There was good rainfall in September 1998 (Decile 8) but the remainder of this season was below average. Rainfall over spring in 1999 was below average at all sites (Decile 3-4) and spring-sown trials in particular were affected. In the 1999/00 season summer rains were early enough to be of benefit to chickpeas and the later maturing lentils but February rains in 1999 delayed harvest of these crops in Zone 3.

Zone 1. Central and Southern Midlands

Low winter temperatures produced poor vegetative growth in chickpeas, narrow leaf and yellow lupins resulting in poor competitive ability against weeds and harvesting difficulties. In an attempt to reduce frost damage, field peas were sown later in the season in 1999/00 but the relatively dry spring resulted in a poor finish so that yields were only a marginal improvement over frost-affected autumn sown plots.

Given the excellent vegetative growth of the field peas over the winter of 1998/99 the option of growing crops purely for fodder was explored in 1999/00. Detailed results are presented elsewhere in these proceedings (2) but dry matter yields have averaged around 10 t/ha.

Surprisingly, autumn sown lentils showed only minimal frost damage. Low plant height at harvest and lack of competitive ability remain as the major problems. Faba beans and later flowering varieties of albus lupins displayed the least frost damage and also exhibited acceptable growth over winter. The newly released faba bean cultivar Fiesta VF recorded an average yield of 2.6 t/ha.

Zone 2. Northern Midlands

Faba beans performed well and the mean yield of Fiesta VF was 5.9 t/ha. In the dry spring of 1999/00, late maturing European lines were significantly lower yielding than Australian cultivars. The broad bean cultivar Aquadulce yielded on average only 5% less than Fiesta VF. There was a surprisingly low incidence of disease with only two fungicide sprays applied to plots in both seasons.

Narrow leaf lupin yields were variable across years with average yields of 4.8t/ha in 1998/99 and 2.7 t/ha in 1999/00. The cultivar Wonga was the highest yielding entry in both years (3.9 t/ha average) and in general the later maturing lines performed better. Yields of yellow lupins were consistently lower than that of narrow leaf lupins at all sites tested.

Compared with narrow leaf lupins, yields of albus lupins tended to show more stability across sites and years but greater variation between varieties. Early maturing cultivars such as Kiev Mutant and Ultra showed some frost damage in primary pods and were over 30% lower yielding than the highest yielding sweet albus lupin cultivar, Hamburg (3.7 t/ha). New late-flowering determinate French cultivars were average or below in yield. High alkaloid albus lupins, as grown in Mediterranean countries for human consumption, were on average 0.5 t/ha higher yielding than sweet types.

In the spring-sown trials, Australian red lentil cultivars generally matured earliest and were consistently out-yielded by green lentils. Later maturing green lentil entries from Canada and Europe performed well in both years and it was evident in 1999/00 they were able to capitalise on rains in late December and early January. These rains probably assisted in obtaining large seed size with green lentils achieving seed weights of nearly 80 mg. Chickpea seed weights were also very high (up to 600 mg for the cultivar Bumper) but grain yields were generally low. Field peas, compared with lentils and chickpeas, showed a greater reliance on spring rains for good yields.

Zone 3. North West Coast

Lentil yields were high in 1998/99 and with an August sowing the season was sufficiently long to produce good yields in both red and green lentils. Yields in 1999/00 were disappointing due to the dry spring and only moderate weed control. Kabuli chickpea yields were not high although seed size was good (up to 490 mg). Rains in early February 1999 delayed harvest and sclerotinia and secondary fungal growth discoloured much of the grain.

DISCUSSION

Tasmanian broad-acre cropping is characterised by small farm, paddock and machinery sizes that result in low economies of scale and relatively high input costs compared with other grain producing states. In addition, products to be shipped to mainland Australia incur high sea freight costs. Consequently to remain competitive, produce must be consumed in the state or satisfy a high value niche market.

Due to the low population base in Tasmania the local market for high value pulses is small and so larger volume markets such as stockfeed rations form the basis for import replacement. Currently around 8000 t of narrow leaf lupins are imported and there is potential to replace this with locally produced grain legumes. Yields of some of the newer varieties of faba beans, field peas, sweet albus and narrow leaf lupins should be sufficient to attract new growers in the Midlands area. Research is also being conducted by the University of Tasmania into dehulling narrow leaf lupins for use in aquaculture rations (Chris Carter pers. comm.). In the Central and Southern Midlands production of fodder peas to be used by the local feedlot as a substitute for lucerne is being trialed commercially.

By far the greatest potential for grain legume crops in Tasmania is to supply niche markets for pulses both interstate and overseas. Fortunately, Tasmania possesses some valuable attributes that provide a competitive advantage. A mild finish to the season and the capacity to irrigate in many areas allows the developing seed to reach a large size, a characteristic commonly associated with price premiums in niche markets. In addition, the climate is more similar to that of many Northern hemisphere countries and introduced material is often more adapted to Tasmanian conditions compared with the main grain producing areas of other states. Farmer experience with growing vegetable and extractive crops is also a valuable asset in producing a high quality product.

Large-seeded bitter albus lupins have attracted excellent prices and although currently small this market is being further developed for overseas export. Grain size is important as there is a rapid decrease in value for produce not meeting size specifications and disposal of high alkaloid grain will be difficult. High returns provide scope for this crop to be grown in all cropping zones including Zone 3 and a cultivar trial is being conducted in 2000/2001 on the North West Coast.

Grain size is also critical for kabuli chickpeas and although yields have been disappointing the large seed sizes produced in Zones 2 and 3 should command significant premiums. Current freedom from ascochyta blight provides a competitive edge. Inopportune rains at harvest may however be a problem for grain quality, particularly in Zone 3, as experienced in 1998/99.

Large seeded green lentils are generally late maturing and there are no cultivars suitably adapted to the main grain growing areas of Australia. Consequently with a longer growing season Tasmania is well positioned to produce large green lentils. In particular, a soon-to-be-released Tasmanian accession has early vigour, good height at harvest and is adapted to spring sowing conditions in Tasmania (Zones 2 and 3). Seed size has been good and future production will remove the need to import significant quantities of this lentil type from Canada. There is also a small market in Australia for the late maturing french green (de Puy) lentils. Following field trials a commercial crop was successfully grown in Zone 3 in 1999/00.

Seed size is also important for maple peas which are currently grown in Zones 1 and 2, largely for sale interstate in pigeon rations. A small quantity of the cultivar Whero is also being used in the sprouting market with plans to shortly trial a blue pea. Marrowfat peas are being evaluated this year on a paddock basis. With large seed size (500 mg), prices received should be significantly higher than other field peas and there is potential to grow marrowfat peas under irrigation or in areas with a good finish, particularly Zone 3. Exclusion of pea weevil from the state is also of large benefit to pea producers.

A premium is generally paid for broad beans and the cultivar Aquadulce has shown consistently good yields. The faba bean cultivar Fiesta VF performed well in trials and commercial crops will be grown in 2001 in Zone 2. Trial results to date suggest greater tolerance of faba beans to late frosts with potential for production in Zone 1.

CONCLUSION

Work conducted in this project has shown there are a suite of grain legume alternatives that are potentially viable for the 3 major cropping zones in Tasmania. The nature of niche markets is such that they are susceptible to large fluctuations in supply and demand and a range of options will allow growers to alternate between crops depending on prices available. It is important to recognise the limitations and capitalise on Tasmania's natural attributes. A number of the pulse crops evaluated provide a competitive edge through being of high value and adapted to higher rainfall cool climate environments. Continuing work will provide information across a range of seasons as well as further developing crop options with the greatest potential.

ACKNOWLEDGMENTS

This research is supported by the Grains Research and Development Corporation. Thanks to Rob Howard and Simon Munford for technical support and to cooperating farmers.

REFERENCES

1. Charleston, K. 1997. Grain Legume Evaluation Report 1996/1997, Department of Primary Industry and Fisheries, Tasmania

2. Dean, G.J. 2001. Proceedings 10th Australian Agronomy Conference, Hobart

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