KYBYBOLITE RESEARCH CENTRE FIELD DAY 1963

Many changes have taken place in the hundred years smce 1861, when the late James Affleck built his homestead at Kybybolite. On the 26,000 acre holding over which some 12,000 sheep grazed there are now fifty holdings which run nearly 75,000 sheep. 

Land tenure and stock carrymg capacity are not the only things to have changed. Most striking has been the soil fertility transformation brought about by the use of superphosphate and subterranean clover.

Kybybolite Research Centre has, since 1905, played no small part in meeting the problems of a changing agriculture.

THIS BOOKLET has been prepared to present visitors to the Centre with an account of some current and past research work. It is hoped that the information set out in the following pages will be of benefit to primary producers generally.

Some facts and figures

Pasture Species

Pasture Species trial

In July 1955, Field 4A was sown to pasture. Eight grass species and mixtures were used:

Establishment varied, being highest for the ryegrasses and least for the timothy.

The field has been maintained for eight years, and the only species still established is Phalaris tuberosa.

Conclusions:

1. Annual grass species (H1 ryegrass, Wimmera ryegrass and Prairie grass) will not persist for more than a few years.
2. Perennial ryegrass will not withstand the dry summer periods under Kybybolite conditions.
3. Phalaris tuberosa is hardy and provides excellent competition for both annual grasses and broad-leaved weeds.

Phalaris Tuberosa - its role in the red gum country

Phalaris Tuberosa is a hardy perennial grass which is outstanding in the red gum country of the South East. First sown in 1930) it has persisted well and when well established is capable of carrying large numbers of stock.

Among its advantages can be listed:

• A long growing season.
• Useful winter production.
• Control of annual weeds, thus giving stability in pastures.
• Persistance under waterlogged conditions.
• Ability to recover from heavy, continuous grazing.

Establishment

Phalaris tuberosa is not vigorous as a seedling, but care and attention which guarantee a successful establishment will be well justified. Recommendations include:

• Autumn-early winter seeding.
• A fine weed-free seedbed.
• Compaction of seedbed by rolling where necessary.
• The use of adequate seeding rates.

Seeding Rates

On old subterranean clover land where soil fertility is high the competition from weeds can be serious, and heavier seeding rates may be justified.

Phalaris rate of seeding trial 1963

Aim: To determine:

1. Optimum seed rate for
   1. Rapid establishment
   2. A balanced pasture mixture
2. Effect of rolling before and after seeding

Design: Factorial randomised block design.

Treatments:

Seeding rates:

1. 1 lb. per acres with 90 lb super.
2. 2 lb. per acres with 90 lb super.
3. 4 lb. per acres with 90 lb super.
4. 8 lb. per acres with 90 lb super.
5. 16 lb. per acres with 90 lb super.

Seedbed consolidation -

1. Rolled before seeding.
2. Rolled after seeding
3. No rolling

Date to be collected:

1. Soil density measurements
2. Plant establishment counts
3. Production cuts and botanical composition.

Pasture renovation

After many years of subterranean clover growth, soil fertility has been lifted to a high level over mush of the red gum country. Invasion of pastures be undesirable annual species is a major problem.

Chief of these are the annual grass species Hordeum leporinum (Barley grass) and Bromus spp. (soft and sterile brome grasses).

A wide range of broad-leaved weeds includes Cryptostemma calendula (Capeweed or dandelion), Rumex spp. (Dock) and Echium plantagineum (Salvation Jane).

Renovation often consists of:

1. Growing one or more cereal crops e.g. oats
2. Use of summer growing fodder crops, such as chou moellier or rape
3. Reseeding to pasture, either annual or perennial

Weed control by cultivation and cropping may not always be effective. Ploughing to establish a perennial pasture has disadvantages:

• Ploughing and cultivating costs are high
• The land is unproductive for a long period

The use of chemicals to destroy weeds ("chemical ploughing") and oversowing with perennial grasses have been investigated recently.    

Diquat Trial

Aims: To determine:    

1. Most economical spray concentration
2. Effectiveness in aiding oversowing of grasses
3. Optimum sowing time in relation to time of spraying
4. Suitability of different grasses.

Design Factorial:-    

Replications:- 

Spray treatment 4
Time of oversowing 2

Data to be collected:-

1. Grass cuts, winter and end of season
2. Botanical composition (levy point quadrat)

Method:-

Time of oversowing

1962

Dry matter production in lbs/acre

Note:-

1. Effective control of capeweed using Diquat
2. Spraying markedly reduced total winter production

It is obvious that unless the capeweed is replaced by another species then spraying is of little or no benefit.

1963

A. Area not oversown
Dry matter production in lbs/acre

Note:-

1. Spraying in previous year has reduced capeweed in following year.
2. Total production on sprayed area however is still well below unsprayed area.

B. Area oversown wth Phalaris tuberosa
Dry matter production in lbs/acre

Note:-

1. Oversowing has slightly increased total winter production (compare with previous table).
2. Oversowing has replaced capeweed with a perennial species which is more vigorous and a competitor against both capeweed and other annuals.

Oats - a valued cereal

Oats can play an important part in the South East:

As a crop in a pasture renovation programme oats give heavy yields from the high fertility built up under clover pasture.

To bridge the winter feed shortage early sown oats are valuable.

The grain is a valuable supplement to weaner sheep and to ewes in the last few weeks of pregnancy.

Many varieties have been tested at this Centre for both grazing and grain. Grain yields have been best from the varieties Avon, Fulmark and Early Kingston; while an unnamed crossbred from Roseworthy College designated OXB 12 (not yet released) has performed very well.

Grains yields from the six leading varieties from 1957-1962 (inclusive) averaged:

Vaieties which have yielded the greatest quantities of forage for winter grazing have been:
APLHA, KENT, FULGHUM, MULGA, AVON

Barley - an alternative grain crop

In 1961 and 1962 the production of barley for both grazing and grain has been compared with oats.

From the figures presented below it will be seen that the barley variety Noyep has given substantially more winter feed than oats. In 1961 Noyep gave a higher grain yield than Avon oats. In 1962 the yields were reversed.

Comparative production of Barley and Oats

Two seasons' results would suggest that greater use could be made of barley for both grazing and grain production.

Maintenance Phosphate Trial

Pastures at the Centre have been regularly topdressed with superphosphate for over 40 years. During that period some soils have had a total application in excess of 3,500 lb. ,

• To what extent has a build-up of soil phosphorous occurred?
• What is the minimum dressing needed to maintain soil fertility and pasture production?
• At what level of soil fertility can phosphate dre~sings be reduced to a maintenance level?

To answer these and other economic questions a long term trial was commenced in 1957.

Aim: To determine:-

(1) minimal dressings of superphosphate (2) frequency of dressings fOT maintenance of (a) soil phosphate level (b) pasture balance (c) pasture production on a pasture of sub-clover and annual grasses.

Design: Randomised blocks

Method:

Grazing 16 Merino wethers per treatment rotated weekly through 4 blocks, i.e. 4 sheep/acres. Superposphate used - 9.6% T.P.- 7.9% W.S.P. .7% C.S.P. 1.0% A.S.P. Total super dressing prior to trial - 3,490 lbs.

Data to be collected:

1. Pasture - Dry weith and chemical analysis - twice/year. Botanical composition (Levy point quadrat) - once/year.
2. Soil - Chemical analysis - once/6 year cycle
   a - pH. b - Total N. c - Organic C. d - Total P. e - Available P.
3. Sheep - Body weights and body scoring - monthly. Greasy wool weights annually. Tattoo patch clippings (clean scoured weight) monthly.

Results:

The first six year cycle concludes at the end of 1963. Results to the end of 1962 indicate:

1. In two winters (1959 and 1962) there were large differences in pasture production between treatments. Plots receiving 56 lb of superphosphate or more in those seasons outproduced plots receiving no super. These figures suggest that lack of readily availablee phosphate may reduce winter production.
2. Total wool per acre has varied between treatments, with the NIL plot producing about 4 lb. an acre (i.e. 1 lb. a head) less wool per annum than the most productive of the fertilised plots.
3. Production of wool, sheep live weights and dry matter production on the nil plots have only dropped below the fertilised plots in the fourth and fifth years of the trial.
4. Plots receiving 56 lb. an acre per annum have produced as well as those receiving 1 cwt. an acre per annum.

Time of mating - effect of fat lamb production

Three groups, each of 100 Border Leicester x Merino ewes, were mated over a six year period (1952-1957) at the following times:
Early mated-December 15-January 25.
Mid-season mated-January 25-March 7.
Late mated-March 7-April 17.
The percentages of lambs marked and of dry ewes were as follows:

The higher lambing percentages in the mid-season and late mated flocks were due to:

1. Higher fertility (number of ewes which lambed)
2. Greater prolificacy (higher twinning in ewes which lambed)

Time of mating Merinos

The Merino flock at K ybybolite has over the years 1960-1963)comprised a normal and a late-mated group.

RESULTS

1. Lambing percentages (% lambs born to ewes mated) have been as follows: