Compendium of Research Projects Completed
Between January 1996 and June 1997

Pasture Seeds

Australia, with its diversity of climate and growing conditions, is able to produce pasture seed ranging from temperate to subtropical species for domestic use and for export markets.

In 1995-96 the export value of pasture seeds exceeded $30 million. In the past two years lucerne has overtaken clover as the major leviable seed crop, with total production of leviable temperate legume seed exceeding 10,000 tonnes.

The main subtropical grasses grown for seed in north-eastern New South Wales, Queensland and the Northern Territory are Rhodes grass, Setaria, panicum, carpet grass and paspalum.

While none of the tropical and subtropical pasture species are currently levied, the industry has indicated its support for a levy on these seeds and this will be further pursued by industry and RIRDC in early 1997. A levy base will provide the scope for an expansion of the research program to include subtropical species.

Research Highlights for 1996-97
· Development of a management support system for seed growers providing management targets to achieving maximum economic seed yields. This has resulted in better insect and irrigation management techniques.
· Production of a manual on pasture establishment and management, which has been well accepted by the farming community.
· Identification of the extent and degree of herbicide resistance in major weeds of legume pasture seed crops.
· Development of an agronomic package to maximise profitability of sub-clover seed crops.

---

LUCERNE SEED CHECK: A MANAGEMENT SUPPORT SYSTEM APPROACH TO IMPROVING LUCERNE SEED PROFITABILITY

Objective

· To increase the rolling average of lucerne seed yield in the Lachlan Valley.

Background

A potential existed to expand existing markets for lucerne seed at a state, national and international level. By accelerating the adoption of seed production technology, growers would be able to increase seed yields through the efficient use of inputs, improving the long term prospects of the industry in the Lachlan Valley and making a valuable contribution to the New South Wales economy.

Research

Through consultation with seed growers a management support system was developed encompassing current technology providing management targets to achieving maximum economic seed yields. A paddock recording diary of key checkpoints was also developed.

During the term of the project growers were expected to utilise the accompanying resource information compiled as an aid in making their management decisions. They were also encouraged to monitor their crops regularly, recording details of field observations, inputs and outputs in the recording diary.

At key checkpoints, grower were expected to participate in group field inspections and workshops. With the aid of visiting specialists and members of the team, growers were assisted in meeting crop management targets in line with the established checkpoint approach. Seed growers were also encouraged to have an input into the progress of the project.

Participating growers were assembled at the end of each season to discuss the results and reasons for varying seed yield and crop profitability. Opinions would also be sought on the format of paddock recording diaries. When undertaking scheduled field observations seed growers were asked to record data and management strategies for analysis at the end of each year.

Implications

The project has resulted in better insect management by growers. A change in the insecticides used and their pattern of use has led to savings to growers whilst reducing the impact on beneficial insects and pollinating honey bees. Tentative economic thresholds and a method of monitoring seed crops has been established.

An outcome of the project is the acknowledgment by growers that plant densities of 15-20 plants per square metre is most desirable in the Lachlan Valley when establishing lucerne specifically for seed production.

More than 60% of growers now undertake both winter and spring weed control programs and are able to correctly identify weeds. Seedgrowers now also have a better understanding of crop pollination and pollinating honey bees.

A "Water Watch" service has been established and is supported by a resource information booklet compiled by the team. The adoption of the use of the "Water Watch" service, improved irrigation management techniques and the fostering of a commercially available Neutron probe irrigation scheduling service has been an important outcome of the project.

Growers understand that to harvest quality seed a lucerne seed crop needs to be free of weeds and sufficiently mature before commencing seed harvest. Failure to have a crop in the correct condition at harvest may lead to increased mechanical damage of seed which reflects on the quality of seed placed on the market. A major achievement of the project has been the acceptance by seedgrowers that most factors contributing to achieving high yields are controllable.

RIRDC Project No: DAN-75A

RESEARCHER: R B Walker
ORGANISATION: NSW Agriculture, 161 Kite Street, ORANGE NSW 2800 PHONE: 063 913 174 FAX: 063 913 605

---

PASTURE ESTABLISHMENT AND MANAGEMENT PUBLICATION

Objectives

· To survey farmers on their current pasture practises.
· To collate information on innovative methods of pasture establishment, renovation and management.
· To publish a 300-400 page manual on the topic.

Background

Pastures are an integral part of Australian farming, and considerable research in directed at solving various pasture problems. New establishment and management strategies are being adopted by farmers, but much of the information resulting from pasture research does not effectively reach the farmer.

Surveys have shown that younger farmers particularly, do not have the knowledge on pasture issues that their fathers had. This has lead to a general failure to maintain soil fertility levels under pastures, and to inadequate control of pests and diseases; a failure to replace pastures which have degenerated; and, a failure to adopt sustainable grazing practices.

The publication resulting material (case studies on successful practices etc) was produced as a pasture manual.

Research

Following surveys of farmer practices in relation to pasture establishment and management, topics were identified on which contributions could be made by pasture experts in the various fields being considered. The resulting material, (case studies on successful practices etc) was produced as a pasture manual.

Outcome

This project has resulted in a high quality book of some 435 pages which has been well accepted by the farming community.

Implications

This book provides, in easily accessible format, all the information which is needed for farmers to establish and maintain pastures in all the temperate regions of Australia. Its use should result in more profitable animal production, and the improvement of crop yields (particularly of grain crops). The information provided should allow the better establishment and management of a wide range of pasture types, and should arrest the decline in general knowledge of pastures which is currently so clearly lacking in younger farmers.

RIRDC Project No: KDI-7A

RESEARCHER: Mark Casey
ORGANISATION: Kondinin Group 177, Great Eastern Highway, BELMONT WA 6104
PHONE: 09 478 3343 FAX: 09 478 3353

---

HERBICIDE FAILURE AND THE NEED FOR INTEGRATED WEED MANAGEMENT IN LEGUME PASTURE SEED CROPS

Objectives

· To establish the extent and degree of herbicide resistance in major weeds of legume pasture seed crops.
· To establish the extent of enhanced biodegradation of carbetamide.
· To identify alternative herbicides where enhanced degradation of carbetamide occurs.

Background

The requirement for largely weed-free pasture seed crops means that seed growers are long-term users of herbicides. Frequently, the same area of land is in production for many years and the same, or similar, herbicides are used year after year. This practice invariably leads to the development of herbicide resistance in the weeds concerned. Herbicide resistance in grasses has become widespread in Australia over the last decade, particularly in seed producing regions such as the south east of South Australia.

The herbicide carbetamide, although relatively expensive, has been widely used by pasture legume seed growers in the Naracoorte-Bordertown region to control ryegrass and silver grass known to be resistant to other herbicides. In recent years, however, growers have reported that carbetamide's performance against these two grasses has been inconsistent. This study was undertaken to determine why carbetamide has not provided the level of grass control that growers have come to expect.

Research

Field and laboratory tests were undertaken to determine whether the lack of effectiveness of carbetamide against ryegrass and silver grass was due to herbicide resistance, or to other factors such as enhanced biodegradation of the herbicide. The efficacy of carbetamide against a range of other weeds was also examined. On sites which had received repeated treatment with carbetamide, enhanced biodegradation was shown to occur. Other potential herbicides for use in this situation were also evaluated.

Outcomes

The inconsistent performance of carbetamide against grass weeds in pasture legume seed crops was shown not to be due to the development of herbicide resistance, but to enhanced biodegradation of carbetamide in the soil after application. Several alternative herbicides including propyzamide, diuron, isoproturon and simazine were shown to be effective against grass weeds and can be used instead of carbetamide.

Implications

As carbetamide resistance does not yet occur in annual ryegrass and silver grass, it may continue to be used in rotation with other herbicides but its application will need to be considerably less frequent than is the current situation if enhanced biodegradation is to be avoided. In the interests of slowing the development of herbicide resistance in annual ryegrass particularly, there should be an alternation of herbicide groupings in an integrated weed management system.

This research provides valuable advice to underpin the ongoing successful production of pasture legume seed crops which are threatened by grass weeds such as annual ryegrass and silver grass.

RIRDC Project No: UA-27A

RESEARCHER: Stephen Powles
ORGANISATION: The University of Adelaide, Waite Campus,
ADELAIDE SA 5005
PHONE: 088 303 7237 FAX: 088 379 4095

---

DEVELOPING AN AGRONOMIC PACKAGE TO MAXIMISE PROFITABILITY OF SUB CLOVER SEED CROPS

Objectives

· To identify key agronomic and management factors limiting seed yield in subterranean (sub)clover seed crops.
· To devise and implement a management package to assist growers in maximising yield and profitability.
· To identify priorities of future R&D into sub clover seed production.
· To collate and summarise existing knowledge on sub clover seed production as a basis for recommendations.

Background

Sub clover is the predominant legume component of pastures in southern Australia. The production of quality seed is vital to its success as a component of pastures and to the introduction of new superior cultivars. Australia grows all its sub clover seed and even exports a small amount.

However, the sub clover seed industry is relatively small and technological problems encountered by growers have rarely been addressed. Yields vary widely within the industry (in NSW from 200-1000 kg/ha) and the reasons for this are not clear. Moreover, yields are far below those in experimental plots which are harvested by hand rather than the commercial suction harvester.

The problem then is one of highly variable yields which, in many cases, means only marginal returns. In addition it is thought that there is also potential for increasing yield amongst the better growers (ie there is a considerable gap between yields in experimental plots and those of the leading farmers).

Research

The research strategy for this project has been to monitor crops newly sown in 1992. For each crop all relevant management data has been recorded. In addition, sampling sites have been established in each paddock and monitored for plant population, weed population, soil conditions (phosphorus, pH, Al and Mn) and yield components. The data was analysed to determine the management factors associated with more profitable yields and crop characteristics that are related to high crop yield.

Outcomes

Soil phosphate was generally at levels known to be limiting for sub clover production. Herbicides were frequently used, but not necessarily achieving long term weed control.

In the establishment year sowing rate and red legged earth mite control were the two most important factors explaining differences in potential yield between seed growers. In the two regenerating years, a suite of factors were implicated by aspects of weed control, current and historical, and cultivar were the common factors influencing yield in these years.

Implications

The use of fertiliser should be increased to ensure crops are grown at optimal levels of soil phosphate. This simple message needs to be addressed by both producers and their advisers. Likewise, in the year of establishment growers should use a sowing rate that will achieve at least 200 plant/m2 and carefully control red legged earth mite.

Future research should concentrate on weed control. Two areas should be addressed:
· effective use of herbicides, including examining the suitability of new herbicides under commercial conditions and examining weed thresholds; and
· cropping systems research - the use of break crops eg cereal/canola to increase the weed control options after (for example) two years of seed production.

RIRDC Project No: DAN-76A

RESEARCHER: Dr Jim Virgona
ORGANISATION: NSW Agriculture Agricultural Research Institute, WAGGA WAGGA NSW 2550
PHONE: 069 381 999 FAX: 069 230 809






Last updated: 22 October1997
Copyright © RIRDC
http://www.rirdc.gov.au/pub/97comp/pasture.html