This paper is a discussion of the establishment of lucerne-based pastures on the properties “Carumbi” and “Carooma”. The farms are run in conjunction with Messrs Peter and Lin Allen as a family partnership based on a mix of cropping and wool producing enterprises in the Grogan district near Temora.

Property Details

Location - The property is located approximately 42 km north-east of Temora on the Bland Creek.

Size - The total land area involved is 880 hectares (2200 acres) of which 400 hectares is normally devoted to cropping. This area ranges from 570 to

330 hectares depending on circumstances. The area of pasture currently includes 360 hectares of lucerne- and clover-based pastures with the remaining area being clover/ryegrass pastures of a lower standard. Currently 120 ha of cereal crops wheat and barley is undersown to lucerne, clover and medic pasture mixes.

Stocking rate - Approximately 3700 medium wool merino sheep, including 1300 breeding ewes,comprise the wool producing enterprise. Stocking rates in terms of dry sheep equivalents (DSE) approximate 8.75 DSE/ha with plans to raise this slightly with further pasture improvement.

Fodder conservation - Includes stored grain of approximately 200 tonnes together with 900 tonnes of pasture and crop silage.

Rainfall - The Temora district is categorised as having a 475 mm (19”) annual average rainfall. However, the Grogan district receives less in total and with less reliability than the nearby centre of Temora.

Soils - With the exception of a small gravel rise the soils are principally red brown earths running through to heavy blue grey clays. The dominant features of these soils are their poor physical structure as a result of their sodic nature, high clay content, and low native organic matter levels. A programme of soil improvement includes gypsum application together with the retention of crop residues for soil structure improvement, and a regular pasture fertiliser topdressing programme. Soil surface crusting commonly results from the poor soil structure, significantly reducing crop emergence. The most positive feature of the soil in relation to lucerne establishment is its basically neutral surface reaction and alkaline subsoil pH.

Table 1. Soil characteristics

Native State		Improved
Phosphorus (P)	range 3-8 ppm (Bray No.1)	25-30 ppm (AFL)
Exchangeable sodium percentage	6-10% range
Organic matter percentage	less than 2%
pH	surface 5.7 to 6.5 (CaCl2) subsurface 8.0 (H20)

The basically flat topography, poor soil structure, indistinct drainage lines and gilgai formations gives rise to areas of periodic waterlogging which is of great significance in selecting pasture species and varieties.

Pastures

Sowing rates - A pasture mix of a total of 5 kg/ha consisting of 2 kg lucerne, 2 kg subcover, and 1 kg annual medics has been used. More recently the quantity of clover has been increased to 4 kg/ha increasing the total mix to 7 kg/ha.

Companion crops include wheat and malting barley sown at rates of 40-50 kg/ha fertilised with 80 kg/ha of AFL Starter 12.

Establishment rates - The lucerne stands established in the last three years have stand densities ranging between 30-50 plants/in² from 2 kg of sown seed. Cover crop densities vary greatly depending on conditions following sowing but usually in the order of 50-75 cereal plants/in².

Table 2. Pasture mixes used

Species	Rate	Variety
Lucerne	2 kg/ha	1 kg highly winter-active	Siriver Sequel
		winter-active	Trifecta
		1 kg semi-dormant	Falkiner Nova Trifecta
Subclover	Range 2-4 kg/ha	Trikkala, Junee, Daliak
Medics	1 kg/ha	Sephi, Parragio, Jemalong
Total Mix =	5-7 kg/ha

Value of improved pasture - Lucerne forms the basis of the improved pastures. Clovers, medics and volunteer grasses may provide the bulk of the feed supply, however lucerne provides the quality. Apart from its obvious high protein feed value, lucerne is also usually available at critical times in the feed supply year, providing a high protein feed source for weaners and young stock in summer and early autumn. Lucerne is also the quickest feed source to respond following rains. We find this to be of vital assistance in dry autumns when stock on supplementary grain or silage respond to even the smallest intakes of lucerne.

Recent changes to the description of wool for sale, including the additional measurements of fibre strength and position of break data, may have impact on sheep nutrition and feeding management.

Lucerne, an important feed source in the late summer-autumn feed stress periods, may act to reduce fibre weakness in the mid-regions of our wool staples. Mid-region fibre weaknesses is an important wool quality fault tending to depress prices received.

Pasture Establishment

The following are our observations from past pasture establishment techniques.

Role of weeds in relation to clover pastures - Poor clover stands in pastures established prior to the availability of in-crop grass herbicides,we have attributed to competition from Wimmera ryegrass (Lolium spp.). The ryegrass, whilst offering only minor competition in the undersown crop, produced a large seed reserve such that, in the first autumn of the pasture, ryegrass seed reserves exceeded clover seed reserves. The vigorous early growth of ryegrass dominated emerging clovers and shaded clover plants in the spring. Research indicates shading to be detrimental to clover seed production, acting to further reduce clover seed reserves in relation to the grasses.

Trifluralin herbicides, incorporated pre-emergent, are now considered an integral part of pasture establishment procedures for the control of ryegrass (Lolium rigidum), canary grass (Phalaris spp) and wireweed (Polygonum aviculare). This, together with a general rundown in ryegrass densities is leading to improved clover and medic pasture densities.

Dry sowing - It was observed from past experience that where circumstances had dictated the sowing of the cover crop and pasture species ‘dry’, that is with no soil moisture, the pastures so established were some of the more successful. One reason for this we believe was that maximum soil moisture was maintained nearer the surface in the zone of the pasture seeds. This is in comparison to a situation where sowing occurred following rain and the associated soil disturbance dried the soil surface layers.

Pre-sowing weed control is of increased importance in such circumstances. However, dry sowing appears to have something to offer in terms of pasture establishment.

Duration of soil moisture near the sown pasture seed - Observations from dry sowing experiences prompted questioning as to how long pasture species, especially lucerne, required soil moisture to last in the zone of the seed, in order that the seeds successfully germinate, emerge and begin to establish. Under circumstances where soil moisture, although ideal for cereal seeds, did not persist near the surface after sowing, reduced pasture establishment densities could be attributed to seedling death from moisture stress. The soil moisture initiating germination and/or emergence in a portion of seeds, however, failed to persist long enough to allow seedlings to develop. Only hard seed or seeds at different soil depths remained to establish later following rains.

The question arises as to what period of ‘soil moisture in the zone of sown pasture seed is required in order to expect satisfactory seedling establishment? Experienced lucerne irrigators indicated a likely minimum period of ten days’ duration was required in order for good establishment. Some research input into further defining this requirement would be of value to far. .rs’ decisions at sowing, especially when considering early or mid-April sowings.

Furrow Sowing

In consideration of the previous factors, deep placement of the seed nearer to soil moisture reserves, whilst still retaining shallow sowing, has advantages. This is achieved by placing seed in the base of furrows, as shown in Figure 1.

Figure 1: Use of furrow sowing to place pasture seed close to the soil surface.

Modification Of Pasture Sowing Machinery

The original modification to our pasture sowing mechanism consisted of a ridge levelling bar, incorporating the seed tubes, to form a crude bandseeder attached to the rear of our standard combine. This avoided deep placement of alternate rows of the pasture seeds in the furrows created by the rear row of cultivating tynes. Whilst this modification was successful, soil diplacement occurring near the combine, especially at higher ground speeds, together with the action of covering harrows, acted to incorrectly place a proportion of the pasture seeds.

The success of a trailed, press wheel bandseeder designed and built by Max Allen of Dulah, near Ganmain, convinced us of the advantages of having pasture sowingdevices mounted on an independent chasis, and remote from the main combine. The freshly cultivated and levelled soil behind the covering harrows of a combine provided a more ideal seedbed in which to place pasture seed.

Description of bandseeder

The bandseeder constructed basically consists of a small seeds box mounted on car wheels and trailed behind our combine. The undercarriage consists of independently sprung tynes (made of angle iron) which create the soil furrows, and to which is welded a pipe to hold the seed tubes. The pressure on the springs is adjusted by means of a lever and chain mechanism and the angle of the seed tubes can be adjusted slightly to vary seed placement. No covering or furrow filling device is involved, the forward speed of the seeder providing sufficient soil movement to cover seeds in the base of the furrows with approximately 15 mm of soil, depending on spring pressure and other settings.

Results of bandseeder

Use of the bandseeder in the last two years of undersowing pastures has resulted in lucerne stands of 30-50 plants/in² being established from 2 kg/ha of sown seed. Optimal sowing and establishing conditions play an important role. However, the shallow placement of seeds by the bandseeder is considered of greatest significance to this success. Assuming 440,000 seeds/kg of lucerne, a 50 plants/in² density represents a 56% establishment success.

It has been observed that the pasture seeds emerge at or before the cereal seeds on most occasions, and in this regard gain a favourable start.

The bandseeder is pulled behind the combine in such a way as to plant the pasture seeds in the same rows as the cereal seeds. The close proximity this affords to the sown fertiliser is considered to enhance early plant growth.

Other Pasture Establishment Techniques Tried

Direct drilling of pasture has been used on occasions in an attempt to upgrade substandard pasture. Weed control was found to be of critical importance. The clovers and medic species may be more adaptable to this method than is lucerne.

Sowing pasture into a prepared seedbed without a cover crop has been successfully used. However, in the particular year it was tried, it was considered that the additional early grazing obtained did not compensate for the loss of even the poorest cover crop yield. The resulting lucerne density could still have been achieved using a very low cover crop sowing rate (say 20 wheat plants/in²). Skip row sowing is being experimented with this year. Every alternate cover crop seed row is blocked off so as to provide a row of pasture seeds without cover crop, yet retaining the fertiliser. This gives a cover crop row spacing of 380 mm and a pasture spacing of 190 mm approximately. It is thought that the reduced early competition from cereal plants may result in improved establishment and survival of pasture plants in the pasture only rows.

Pasture Management

The aim of our pasture management has been to obtain maximum livestock performance in terms of wool production per hectare and maintain a productive pasture for 4 to 5 years. Highly winter-active lucerne varieties are combined withmore dormant varieties, the former providing good early production and the latter included for persistence. The established pastures revert to clover and medic dominance as the lucerne stand density declines.

Lucerne pastures are stocked as heavily as mob size and paddock size dictates. We aim to graze paddocks as quickly as possible, ideally 10-14 days. The lucerne is not grazed on a strict rotational system. Future additional subdivision may permit this, providing improved lucerne stand persistence.

The initial stocking of newly established pastures is restricted to light quick grazings and is determined largely by seasonal conditions.

I believe a useful guide to lucerne grazing management is to observe the crowns of grazed lucerne plants for emerging new regrowth shoots - ideally, this indicates that stock should be removed. It is always hoped that conditions will allow lucerne to flower at some time through the year, this being claimed to be of importance in replenishing lucerne root reserves.

Pastures have been fertilised with 120 kg/ha of superphosphate annually.

Current soil tests conducted by Australian Fertilizers Limited (AFL) showing soil phosphorus levels of 25 to 30 ppm indicate a change to bi-annual topdressing or annual topdressing at reduced rates as a maintenance ration to be most economic.

Weed control in pastures is achieved by grazing combined with spray-grazing and spraytopping with herbicides. It is hoped to maintain pastures as weed- free as possible, especially with regard to black oats (Avena spp.), in order to obtain the cheapest re-entry to cropping cycles.

Conclusion

In conclusion, improved pasture establishment has resulted in increased stocking rates and financial returns. The improvement in established pastures was achieved through examination of past pasture performances and the construction of a trailed bandseeder.