This paper sets the scene for the 1987 Riverina Outlook Conference “Realising the Potential of Pastures” by examining farmer attitudes and practices to pasture establishment after cropping. The information presented is taken from a survey of sheep - wheat farmers conducted in north - east Victoria in 1980. The survey was undertaken to provide a background to the problems that farmers were then experiencing in re - establishing their subterranean clover pastures after a period of cropping. (No pasture research officers had been stationed at Rutherglen Research Station, as it was then, for some 8 years prior to my arrival in 1980).

Whilst the survey was principally designed to answer the question “Did the clover establishment problem on the cropping soils need a research or extension input?”, it did generate a valuable body of information on how farmers established their pastures. With subsequent and significant inputs into pasture research and pasture extension from Rutherglen, many of the problems and incorrect farmer practices highlighted by the survey have now been corrected. Nevertheless, it serves to remind farmers that they must make the best use of the available information and advice to ensure they do realise the full potential of their pastures.

Most of the sheep - wheat belt of north - east Victoria was covered by the survey, in an area bounded by four highways (Hume, Midland, Goulburn Valley and Murray Valley) and one railway line (Springhurst - Rutherglen). In all, 100 farmers who had established subterranean clover in 1980 were interviewed and the clover densities of their 100 undersown pastures counted.

Farmers were selected at random in the field by interviewers canvassing their selected locality. These canvassers simply called in unannounced at farms, asking if any subterranean clover had been undersown on the property; if so, the farmer was then invited to participate in the survey. Surveyed farms were marked on a largemastermap (1:1000,000) to try and achieve an even - as - possible distribution across the survey area.

The 20 questions asked of farmers dealt with all aspects of subterranean clover establishment under a cereal cover - crop, as the following discussion of the ‘results shows. Note that not all numbers add up to 100, because of either incomplete information or overlapping descriptions.

Paddock Details

Soil Type

Although answers to the question about the soil type of the paddock varied from general to detailed descriptions of soil texture, just over half of the 100 farmers surveyed considered they were farming a loam rather than a sandy or clay soil.

Area Undersown

The average area sown was 29 hectares (ha), although paddocks as small as 4 ha and as large as 160 ha were established.

Length of Cropping Period

Table 1 shows that 3 years of crop was still widely practised by most farmers who were re - establishing their pastures in 1980.

Table 1. Years of crop, including the 1980 cover crop

Years	No. Farmers
1	2
2	11
3	64
4	17
5 or more	4

Rotations

The most popular rotation of wheat - wheat - oats was practised by 29 farmers; the next most popular rotations were wheat - wheat - barley, wheat - wheat - wheat and wheat - wheat. The numbers of farmers using these three rotations were 9 each.

Despite the widespread adoption of lupins in north - east Victoria in the late 1970s (an estimated 30,000 ha; Reeves et al. 1980), only five farmers included lupins in their rotations. On the other hand, nine farmers described their rotation as ‘a fallow followed by two wheat crops’. In addition, given that most farmers (4/5) had only cropped for three years or less, suggests that the farmers establishing subterranean clover by undersowing in 1980 were:

(i) more livestock - orientated, and therefore

(ii) less committed to continuous cropping, or at least longer periods of cropping, and/or

(iii) represent the more conservative end of the farmer spectrum.

Cover Crop Details

Type of Cover Crop

About half of the farmers surveyed used oats as a cover crop for the undersown clover (Table 2). At least seven oat varieties were sown, with Avon (13 farmers), West (12 farmers) and Coolabah (9 farmers) the most popular varieties. Egret was the most widely undersown wheat variety (15 farmers); barley varieties included Resibee, Lara, Parwan, Research and Clipper.

The most likely reason for the preference for oats as a cover crop is that the paddock’s fertility would not profitably carry a third wheat crop. Nevertheless, the most interesting fact about the main oat and wheat varieties used for undersowing is that they are generally too ‘flaggy’ and tiller too thickly to be suitable for successful undersown clover establishment.

No question was included in the survey about whether or not farmers intended to graze the oat cover crops during the winter, thereby overcoming some of the above criticisms.

Table 2. Species of cover crop

Cover Crop Oats	No. Farmers 52
Wheat	30
Barley	19

Currently, some of the available cereal species and varieties (for example, Echidna oats and triticale varieties in general) are much better suited to undersowing than some of the now outclassed varieties used in 1980.

Sowing Rates of the Cover Crop

It is generally recommended that the sowing rate of the cover crop be reduced to 40 kg/ha to give the undersown clover every chance of successful establishment Few farmers followed this advice, with most (3/4) continuing to sow their cereals at rates closer to the recommended cereal rates (Table 3).

Table 3. Sowing rate of cereal cover crop

Sowing rate (kg/ha)	No. Farmers
	Total	Oats	Wheat	Barley
<40	2	2	0	0
40 - 60	22	12	1	9
60 - 80	58	27	22	9
>80	14	8	6	0

Pasture Sowing Details

Sowing Date

In 1980, the autumn break commenced at Rutherglen with 11 mm of rainfall falling between April 17 and 21, followed by a further 24 mm on April 24. When soil moiture permits, pasture sowings should ideally occur before the main cereal sowings, preferably in mid - April, in north - east Victoria. The recommended sowing date for wheat in the Rutherglen district in 1980 was May 1. The data presented in Table 4 suggests that the sowing dates of the undersown clover were still largely determined by the priority given to the wheat sowing and its recommended sowing date.

Table 4. Sowing date of undersown clover

Sowing date	No. Farmers	Total Oats	Wheat	Barley
early April	2	2	0	0
mid April*	5	5	0	0
late April	9	8	1	0
early May	25	20	2	3
mid May	33	8	13	12
late May	16	7	8	1
early June	8	1	5	2
midJune	3	1	1	1

*autumn break rains commenced in latter part of this period

Clover Sowing Rate

Traditionally, subterranean clover was undersown at ‘2 lb/ac’ or 2.3 kg/ha.

The sowing rates used by the majority of surveyed farmers was not

significantly greater than this rate (Table 5), with an overall average of

3.4 kg/ha.

Table 5. Clover sowing rate (kg/ha)

Sowing rate	No. Farmers
(kg/ha)
<2	4
2 - 4	73
4 - 6	17
>6	5

In more recent years, higher rates of clover seed are being recommended for establishment (6 - 10 kg/ha) to ensure a more productive pasture earlier in the pasture phase. Often these rates are coupled with the recommendation to direct seed into the old stubble in the following autumn.This is because the competition under a cereal crop when high rates of clover seed are used markedly reduce potential clover seed yields, and so negate any advantages gained from sowing higher rates.

Clover Establishment Method

The traditional method of dropping the seed onto the soil surface from a small - seeds box and covering with harrows was most widely used by the surveyed farmers (Table 6).

Table 6. Method of sowing clover

Sowing method	No. Farmers
Dropped from small - seeds box	79
Broadcast and harrowed
Mixed with fertiliser and drilled	15
Mixed with cereal seed and drilled	7

Mixing the clover seed with either the fertiliser or the •grain often resulted in the clover seed being sown too deeply. Less than 20 mm is recommended, and 10 mm depth is preferred. Most (13/22) were sown at 30 mm or deeper.

Clover Cultivars Sown

Although Woogenellup dominated the pasture establishment scene in 1980 (Table 7), Trikkala has now become the most widely sold cultivar in the cropping areas of north-east Victoria.

Table 7. Subterranean clover cultivars sown in 1980

Cultivar	No. Farmers	% Certified
Woogenellup	64	73
Mt. Barker	15	79
Bacchus Marsh	13	50
Trikkala	5	100
Daliak	3	100
Seaton Park	3	100
Howard	2	77
Esperance	2	100

About half of all subterranean clover seed sold in the last two or three years was Trikkala; although Woogenellup has been relegated to second place, it is still sold in significant quantities in some localities. Little Mt Barker is now sold into the cropping areas, although significant amounts of its replacement, Karridale, are going into the higher rainfall, permanent pasture regions. Bacchus Marsh is, however, still preferred by many farmers who have the flexibility to irrigate their annual pastures.

Clover Seed Inoculation

In 1980, only one in eight farmers inoculated their clover seed and only two of those 13 farmers also lime - coated their seed (Table 8). With the discovery that many cropping soils in north - east Victoria contained few or no Rhizobium, the need for farmers to inoculate their clover seed was again strongly emphasised and promoted by the Department and by Rutherglen in particular. My expectation now would be that a majority of farmers inoculate their clover seed.

Table 8. Inoculation of clover seed, 1980

Inoculation practice	No.Farmers
Uninoculated seed sown	87
Inoculated seed sown	11
Inoculated and lime-coated seed	2

Seed Quality and Source

Tables 7, 9 and 10 illustrate that most farmers (7/10) sowed certified clover seed.

Table 9. Clover seed quality, 1980

Seed	No. Farmers	Quantity Sown
		(kg)
Certified	72	7,300
Uncertified	28	2,500

Where farmers obtained their seed from commercial sources such as specialised seed growers or seed merchants, it was all certified. However, where farmers grew their own seed, or obtained it from a neighbour, or ‘a local farmer’, their commitment to using certified seed declined markedly (Table 10).

Table 10. Sources of clover seed

Sources (No.)	No. Farmers	Seed (kg)	% Certified
Specialised growers (5) Seed and	18	2,300	100
produce merchants (19)	28	2,300	100
Harvesting contractors (2)	29	2,900	72
Local farmers (13)	15	1,100	33
Own seed	10	1,100	12
Other	1	100	100

Perhaps the reason for this decline is that these farmers knew the quality of their seed or their seed source and did not need an official certification certificate to confirm it. Or, alternatively, they do not care as much about the quality of the seed as they do about its price. However, increasingly, farmers cannot afforda pasture establishment failure resulting from the false economy of cheap seed.

Companion Grasses

Most farmers established just subterranean clover under their last cereal crop (Table 11). Including a grass in the sowing mix under the cover crop increases the competition for light, water and nutrients. For example, the vigour of annual ryegrass may compete successfully with the clover, whilst on the other hand the less vigorous cocksfoot, phalaris and lucerne seedlings would struggle to successfully establish against the clover and the crop.

Table 11. Companion pasture species undersown with the clover

Species	No. Farmers
None	84
Ryegrass	9
Cocksfoot	5
Phalaris	1
Lucerne

Perhaps, however, the major reason why many farmers did not include a grass in their pasture seed mix was that they had spent considerable time and money on herbicides keeping previous crops clean of weeds like ryegrass. Hence, they were reluctant to deliberately reintroduce ryegrass under the last crop.

Fertiliser Details

The types and rates of fertilisers used on the undersown crops essentially reflect the priority given to meeting the nutrient needs of the cereal crop, and not necessarily the nutrient needs of the undersown clover (Table 12).

Table 12. Fertilisers used on the cereal cover crop

Fertiliser	No. Farmers	Average Rate
		(kg/ha)	(Range)
Single superphosphate (9.1% P)	81	109	(62-250)
Molybdenum (0.015%) superphosphate	1	100
Double superphosphate (17.5% P)	12	63	(45-134)
Other phosphatic fertilisers (15-19% P)	5	69	(26-112)
Ammonium-superphosphate	1	134
Urea	1	90

As most of the undersown clover was dropped on the soil surface through a small - seeds box (Table 6), there is little point in trying to meet the nutrient needs of the clover when the seed is not placed close to the fertiliser. If super - lime or molybdenum is needed for clover establishment, the clover seed must be drilled in so that it is placed close to the fertiliser band.

Table 13 illustrates that few cropping soils have adequate levels of soil phosphorus for clover growth at the end of their cropping phase. Thus, very little of the fertiliser sown with the crop(s) carries over into the pasture phase for the newly - establishing clover pasture. Careful consideration of the phosphorus requirements of the new pastures is therefore necessary.

Table 13. Soil phosphorus status of 31 cropping soils re-entering a pasture phase, January 1981

Soil P status	% Paddocks
Low (<8 ppm Olsen P)	45
Marginal (8-12 ppm Olsen P)	48
Adequate (>12 ppm Olsen P)	6

Weed/Insect Management

Very few farmers used herbicides on their undersown crops (6/100), and then only to control annual ryegrass (Table 14). Either their previous crops were very clean from good hygiene and weed management or they were reluctant to use herbicides with the clover underneath.

Table 14. Herbicide usage on the cover crop

Herbicide usage	No. Farmers
Nil	71
Pre - sowing, incorporated	22
Pre - sowing, knockdown	2
Post - emergent, for grass control	6

A similar picture emerges with insecticides (Table 15); either there were no major outbreaks of pasture pests, particularly red - legged earthmite (RLEM) in the autumn/winter of 1980, or farmers were again reluctant to use insecticides.

Table 15. Insecticides used on the cover crop

Insecticide usage	No. Farmers
No insecticide	90
Lindane - super
Boom spraying for RLEM	9

Establishment Success of the Undersown Clover

The density of undersown clover plants was averaged from counts at 10 spots in each of the surveyed paddocks (Table 16).

Table 16. Density of undersown clover plants, July 1980

Plant density (No./m 2)	No. Sowings
<30	43
30 - 60	41
60 - 90	9
>90	5

When the larger - seeded clover cultivars Trikkala and Woogenellup

(110 - 120 seeds/g) are sown at 6 kg/ha, 60 - 70 seeds/in2 result. Assuming that 50% of these seeds germinate and successfully establish as young plants (which is probably a realistic expectation at this stage in

undersown crops), there should be about 30 - 35 plants/in2. The data in Table 16 indicates that about half of the crops examined exceeded what I would consider is a minimum density.

However, other calculations suggest that the values in Table 16 might be inflated. Table 17 shows the number of established plants as a percentage of the number of seeds sown. (The number of seeds sown can be calculated from the clover sowing rate and the seed weights for each cultivar).

Table 17. Clover plants established, as a percentage of seeds sown.

% Establishment	No. Sowings
<50	15
51 - 75	25
76 - 100	22
101 - 125	12
>125	24

In this table, a 100% establishment means that all seeds sown germinated and survived to July as young plants. Allowing a 25% margin for variations in sowing rates and seed weights, 24 of the sowings are still greater than the upper limit of 100%. As the canvassers conducting the survey were not expert in distinguishing clover species and cultivars, native clovers such as suckling and cluster clover may have been included in the counts. As well, any subterranean clover surviving from the previous pasture phase would have also inflated the counts.

Given this possibility, the number of sowings showing less than a 76% successful establishment may be significantly greater than the 40 shown in Table 17. In reality, probably about half of the 98 sowings surveyed were less than satisfactory.

The seed yields measured in 32 of the surveyed paddocks at the end of year support this conclusion (Table 18).

Table 18. Seed yields and seed increase of undersown clover, January 1981 (32 sowings)

Yield (kg/ha)	%	Seed Increase
<5	56	<1 fold	44
5 - 10	16	1 - 10 fold	47
>10	28	>10 fold	9

Mean seed yield: 11.1 kg/ha

Mean sowing rate: 3.9 kg/ha

Mean seed increase: 2.85 fold

Seed yields were generally poor, with 70% setting less than 10 kg/ha (Table 18). Also, about half of the undersown stubbles contained less seed than was actually undersown. In situations where the recommendations for undersowing are followed, and no soil problems exist, a 5 - to 10 - fold increase in seed set over seed sown could be expected.

However, not too much ‘gloom and doom’ should be attached to the data in Table 18, as 20 of those 32 paddocks were deemed as ‘problem establishments’. Also, this survey identified that, in addition to the incorrect or inappropriate establishment methods used by farmers, as discussed above, other problems with clover establishment existed. Subsequent research has revealed that inoculated clover seed, super - lime and molybdenum fertiliser and broadcast lime have essentially overcome these effects on clover establishment.

References

Reeves, T.G. and Hirth, J.R. (1982). Survey of undersown and established subterranean clover pastures in the North - East of Victoria, 1980. Department of Agriculture, Victoria. Research Project Series No. 122. January 1982.

Reeves, T.G., Ellington, A. and Boundy, K.A. (1980). 1980 Rutherglen Research Institute Cropping Field Day Notes, p.7.