Program 2 Sustainable Production Systems

Program 2 Sustainable Production Systems

Program Leader:

Dr Graeme Batten

NSW Agriculture

Yanco

Rice CRC Program 2 addresses strategic issues relating to the long-term sustainability of rice production. The objective is to develop a comprehensive understanding of the mechanisms operating in the soil, plant and biological environment that could be manipulated to achieve high grain yield and high quality while minimising the impact of intensive rice production on the environment. Program 2 seeks a sound understanding of the current requirements for rice production and techniques to reduce the impact of rice on the resource base to ensure sustainable rice cropping for the long term. Significant reductions in water requirements per tonne of rice are sought through improved tolerance to cold, better recovery of applied fertilisers and reductions in chemical usage.

During the third year of this Program, 19 projects were in progress. Activities included collecting soils, analysing soils for chemical properties, growing and collecting rice plants to study reactions to cold, studying the influence of nutrient supply on yield and grain quality, and seeking non-chemical crop protection.

Scientists in Program 2 continue to develop valuable linkages with staff and students in many Rice CRC projects, with RIRDC projects, and with scientists at other Australian and International Research Centres.

Specific goals are:-

• an improved understanding of the changes in soils used to grow rice to achieve higher yields per unit of water and fertiliser input;
• an enhanced understanding of the ability of the rice plant to respond to changes in its environment, specifically rice which can withstand minimum temperatures 4ºC lower than current varieties at the reproductive stage;
• the development of tools that can be used to monitor soils, the rice plant and its environment. At present the focus is on a reliable nitrogen test for rice soils;
• a technique to grow grains with predetermined mineral or quality traits; and
• decreased dependence on agricultural chemicals for weed and insect control and to maintain comparative freedom from major pests and diseases.

2.1 Managing soil chemical, physical and biological properties to achieve yield and environmental quality

Sub-Program Leader:

Assoc Prof Scott Black

Charles Sturt University

Wagga Wagga

The state of the soil resource and our ability to manage it are pivotal to rice production.

Nitrogen is a key nutrient in rice production so techniques are required to estimate pre-sowing fertiliser demand and to ensure crop utilisation of the fertiliser.

An inventory of the current status of the soil resource in terms of long-term trends in fertility as well as spatial variability within fields is needed to define potential limits to future production.

A strategic soil nitrogen test for flooded rice (2101)

Project Leader:

Assoc Prof Scott Black

Charles Sturt University

Wagga Wagga

This project aims to develop a rapid strategic soil nitrogen (N) test for aerially sown flooded rice (Oryza sativa). Both a physical test (Near Infrared Reflectance, NIR) and chemical tests (soil C:N and incubation-N) have been evaluated for their abilities to predict rice N uptake at panicle initiation (PIN) from field control plots. The project follows three lines of research; (i) attempts to calibrate the physical and chemical tests, (ii) extensive evaluation of NIR methodology and (iii) implementation and refinement of the most superior soil N test. Calibration of the soil N tests will have three phases; (i) preliminary calibration for archived soils with complementary PIN data, (ii) extended calibration from the inclusion of a large number of soil types/histories with complementary PIN data, and (iii) investigating the mechanism of the calibrations from a comprehensive analysis of soil properties.

Progress

Soil NIR calibration investigations were most effective for the prediction of mature rice agronomic properties, these properties being; grain yield (GY), maturity dry matter (DM) and N yield (NY ie N in tops at maturity). For each agronomic property two spatial scales were evaluated; Riverina - calibrations from all sites, and Western Murray Valley (WMV) - calibrations from those sites located in the WMV, a region known for its distinct soil type. Given the ideal weather for yield conversion in 1999, GY, DM and NY were all highly correlated (R > 0.90). NIR predicted rice NY within 36 (Riverina) and 8kg ha^-1 (WMV). NIR was superior to soil C:N (R²<0.1) and incubation-N (R²<0.5) in explaining all agronomic properties. NIR predicted the mature agronomic properties from the Riverina-wide soils within 20% of their range, and from the WMV soils within 10%. The dramatic increase in predictive ability within the WMV soils is attributed to their similar mineralogical influence on the soil NIR spectra. While NIR calibrations for PIN at both scales were unstable and seriously underestimated high N fertility sites, the relationship between PIN and the mature agronomic properties (R² ~ 0.70) suggests that PIN could be more accurately estimated indirectly from a soil NIR calibration for these parameters. A rigorous evaluation of NIR calibrations and cross-season predictions can now be made with the inclusion of more than 50 sites from the 2000 season.

Use of airborne digital imaging to assess within-paddock variability in rice production (2102)

Project Leader:

Dr David Lamb

Charles Sturt University

Wagga Wagga

This project will:-

• evaluate the ability of airborne digital imaging to detect and map variability in the rice canopy and thereby direct in-field sampling to determine causal factors;
• examine the link between crop yield and airborne-derived maps of variability in emergence and canopy vigour; and
• investigate the role of airborne digital imaging as a means of improving the accuracy of computer model predictions by extending models to incorporate within-field variability.

Progress

Stringent pre-processing methodology was established for the imagery with programs written to facilitate this process. The programs were specific to the problems of the imagery. Calibration of the imagery was also established.

Ground field measurements were analysed and prepared for use in conjunction with the model.

The FORTRAN code of the maNage rice model was modified to accept biomass estimates at various times throughout the season.

After correction and calibration of the imagery, the spectra were extracted from each geo-referenced image for each of the 50 sample points. Preliminary correlations were investigated. The best correlation between the imagery and ground cuts was established using the calculation of the normalised difference vegetation index (NDVI).

Dr David Lamb (CSU) checking equipment used to record airborne digital images of rice crops. (Photograph provided courtesy of "Trevor Ward, Photographer")

Quantifying the long-term effects of rice farming on soil properties (2103)

Project Leader:

Dr Harnam Gill

NSW Agriculture

Yanco

The aims of the project are to:-

• evaluate the long-term impact of the common rice farming systems on the changes in important properties of the prevalent soils; and
• establish sites typical of the Australian rice farming systems for future monitoring and quantitative assessment of changes in the soil properties pertinent to sustainable rice productivity.

Progress

Soil samples were collected in 1998/1999 and in the second half of 1999, from rice paddocks within the Murrumbidgee, Coleambally and Murray Irrigation Districts. In all, 378 soil samples composite surface (0-10cm) and sub-surface (10-30cm) samples were collected. Initially, these samples are being analysed for total soil C, N, and S (by combustion), pH, EC, total P, available P, and exchangeable cations (Al⁺⁺⁺, Ca⁺⁺, Mg⁺⁺, K⁺, and Na⁺).

Collection of information on history of rice paddocks sampled in 1998 and 1999 is in progress. Its collation with analytical parameters will be done this year. Some of the analytical results on the soil samples collected in 1998 are presented below. Variation due to different soils, cropping systems, cut and fill areas etc., is being partitioned.

· Total Soil C, N and S

Total C in surface (0-10cm) soil of rice paddocks ranged between 7.4g/kg on recently cut area of a rice paddock to 42.2g/kg in the native woodland adjoining a rice paddock. (Figure 7 a,b). Mean and median were 17.2 (1.72%) and 17.3 (1.73%)g/kg respectively. Considering documented literature, most sites are moderate in soil C.

Figure 7 a & b. Total soil carbon and its relationships to total soil N (_), S (_), and C:N ratio (_).

Total soil N was about 10 times lower than the soil C levels in the surface layer of rice paddocks. A highly significant relationship between total soil N and C was observed and is presented below:-

Total soil N = Total soil C x 0.0829 + 0.0942, r² = 0.94^*** (N =137)

However, the relationship between total soil C and S was not as good.

Total soil S = Total soil C x 0.00905 + 0.028, r² = 0.58^*** (N =137)

From these relationships, it is evident that the N supplying capacity of the rice paddocks is primarily dependent on the soil organic matter whereas both organic and inorganic constituents influence S supplying capacity. However, a poor correlation between total soil C and the C:N ratios of different rice paddocks indicate significant variation in N supplying capacity and its availability. Considering current use of nitrogenous fertilisers in rice and 50-55% recovery of applied fertilisers, a further decline in the soil organic matter is possible.

· Soil Acidity and Salinity

There is moderate to high acidity in the surface (0-10cm) layer of most rice paddocks but comparatively less acidity in sub-soil (10-30cm) (Figure 8). The range of pH values suggests that productivity of crops, especially legume grains or pasture, when grown in rotation with rice may suffer. However, rice productivity may not be affected as it is grown under waterlogged conditions which are known to increase the soil pH. These conditions also restrict the nitrification process that is known to acidify the soils. Thus, rice has a role in ameloriating soil acidity to some extent.

More than 95% of sites had surface soil (0-10cm) EC_1:5 less than 0.2 dS/m (Figure 8). Only one sample was saline. The EC of the sub-soil (10-30cm) was also not very high except in a few rice paddocks or freshly cut areas. Waterlogging in rice also helps in ameloriating soil salinity through leaching of soluble salts. There was no relationship between EC and pH of the soil (Figure 8).

Figure 8. Relationship of soil pH and EC of surface (0-10cm _) and sub-surface (10-30cm _) soil in rice paddocks.

· Future work

When all soils are analysed the impact of rice on soil properties important for sustainable rice productivity will be reported.

Rotation Trials (2105)

Project Leader:

Mr John Thompson

NSW Agriculture

Deniliquin

The aim of the project is to maintain the rotation site at the Deniliquin Field Station of NSW Agriculture. The site was established to study the effects of saline groundwater use on common rotation crops in the rice growing system. Saline water is applied to the crops in the rotation phase and effect on yield of all crops, including rice, in the rotation is recorded.

Progress

The final crop has been harvested. Rice grain yield (12.1 t/ha) was not affected by the application of saline groundwater to the previous wheat and subclover phases. Thus, only once, from eight occasions have rice yields been influenced by the application of saline groundwater to the prior phases of the rotation.

Soil samples are being collected from all plots and will be analysed for salinity and sodicity.

2.2 Crop management in relation to environmental change

Sub-Program Leader:

Mr Rob Williams

NSW Agriculture

Yanco

Temperature at the reproductive stage is the most important contributor to the yearly variation in grain yield, with cool night temperatures prior to flowering drastically reducing yields. The average commercial rice yield in 1996, for example, was only 6.5 t/ha, compared with the record 9.4 t/ha in 1998, with some crops in 1996 yielding less than 1 t/ha - a devastating result for those growers. Irrigation water is used to protect rice from cold. It is recommended that water depths be increased to at least 20cm during the sensitive developmental phase to maintain the temperature of the developing panicle. This requirement limits the options for alternative water application regimes.

Cold at the reproductive stage particularly affects pollen development. The most sensitive stage is understood to be the early microspore stage, just following pollen mother cell meiosis when single pollen grains are just beginning to fill with starch.

Rice CRC projects are particularly aimed at understanding and eventually improving the response of rice to cold at the reproductive stage.

Cold physiology at the plant level (2201)

Project Leader:

Mr Rob Williams

NSW Agriculture

Yanco

The aim of the project is to identify low temperature tolerant rice varieties in the glasshouse and field environments by developing a screening technique at flowering.

Progress

· Industry Model

An Australian Rice Industry Model (ARIM) has been developed in this Sub-Program. ARIM uses seasonal weather data to predict the future rice crop as well as estimating historical levels of low temperature damage. ARIM successfully predicted the lower rice yield in the 2000 harvest (with an error of 0.5 t/ha) prior to the commencement of harvest. The reduction in yield was due to low temperatures during the critical late January period. ARIM's in-season prediction was used by Ricegrowers' Co-operative Limited to determine storage and handling operations.

· Field Trials

Field trials at Yanco aimed to confirm the cold tolerance in the field of lines known to differ in previous temperature controlled experiments. The 1999/2000 field trial at Yanco comprised of six sowing dates staggered from October 5 to December 30, 1999 with a deep and shallow water treatment at the critical early microspore stage. Twenty-eight varieties from different origins and levels of cold tolerance were replicated in each of the 12 bays. The low night temperatures during late December-early January and late January caused significant levels of sterility in most varieties in at least one of the shallow water treatments. Amaroo, which is considered to be a moderately tolerant variety, performed better than expected in trials at Yanco and also across the whole industry where it yielded 8.5 t/ha. Liman (Russia), M103 (America) and Hitomebore (Japan) had a low level of sterility despite experiencing low temperatures during late January. Sprint (Russia), Doongara (Australia) and Leng Kwang (China) had high levels of sterility in shallow water treatments and appear to be susceptible to mid-season low temperatures.

· Facilities

A new chilling unit for the temperature controlled rooms that improves the reliability of the cooling system has recently been installed.

· Glasshouse Trials

A temperature controlled experiment was conducted to test the cold tolerance of 120 lines from crosses from Millin, Illabong, HSC 55 and Plovdiv 22. HSC 55 (Hungary) and Plovdiv 22 (Bulgaria) have been identified in previous experiments as being cold tolerant. The day/night temperature of 26/13ºC did not induce adequate sterility to identify tolerant lines, however Plovdiv 22 appeared to have epistatic gene action.

1999/2000 field trial at Yanco Agricultural Institute

Cellular biology of chilling induced pollen damage in rice (2203/2204/3202)

Project Leader:

Dr Bruce Sutton

University of Sydney

Sydney

These projects have been transferred to Sub-Program 3.2 (3202). See Program 3 report.

Effect of nitrogen and low temperature on reproductive development (2205)

Project Leader:

Dr Shu Fukai

University of Queensland

St Lucia

The aim of the project is to investigate the effects of nitrogen and low temperature on the reproductive development and spikelet sterility in rice.

Progress

Completion of the second glasshouse experiment and the field experiments for summer 1999/2000 was the milestone for this period. In the glasshouse experiment completed in February 2000, the effects of panicle and root temperature on the spikelet sterility were investigated, particularly in relation to nitrogen fertilisation. Spikelet sterility was significantly increased in plants with low temperatures in both the panicle and root zone (18/13°C) during the microspore development period (seven days). However, it appeared that the warm shallow water during the low air temperature treatment had a significant protective effect on the pollen development. This was further confirmed by reverse treatment in which cooler root temperature increased spikelet sterility significantly despite having warm air.

The critical microspore development period of the crops sown at Yanco in early October coincided with the average minimum temperature <13°C. The similar development stage of late sown crops was observed during the period of relatively warmer minimum air temperature. The yield and yield component analysis of this experiment is in progress.

2.3 Mineral Nutrition and Grain Quality

Sub-Program Leader:

Dr Graeme Batten

NSW Agriculture

Yanco

Rice yield, grain quality and human nutrition are all influenced by the minerals available to roots and taken up by the plant. There are indications from intensive rice farms in the Murrumbidgee Irrigation Area (MIA) that mineral deficiencies may be impacting on some quality attributes. A better basic understanding of factors which influence the uptake and translocation of nutrients within the rice plant, especially to the grain, will place the industry in a better position to sustain rice yield potential and compete for markets which use grain quality and nutrition standards.

The projects aim to gain a basic understanding of the factors which influence the uptake and translocation of minerals and their impact on production and quality. The staff is comprised of three scientists, two technical officers, one postgraduate student and one honours student.

Rice Plant Nutrition and Physiology (2301)

Project Leaders:

Dr Graeme Batten

NSW Agriculture, Yanco

Dr Lindsay Campbell

University of Sydney, Sydney

The trace elements iron and zinc are receiving attention from plant and human nutritionists. In this project Mr Rob Duncan aims to establish links between trace element distribution in the rice plant and grain quality, as part of a higher degree.

Progress

Field, glasshouse and detached panicle techniques have been used to obtain grains with natural or induced variation in Fe and Zn. Relations between micro and macro elements will be examined.

Genotypes with a naturally high Fe and Zn content were imported from the International Rice Research Institute, Los Banos, The Philippines. These have been studied, along with Australian genotypes, under quarantine at the AQIS facilities.

Mr Rob Duncan, postgraduate student (left) and Dr Graeme Batten (right) in the Australian Quarantine Inspection Service importation facilities at Eastern Creek sampling high iron rice genotypes.

Mineral requirements (2302)

Project Leader:

Dr Graeme Batten

NSW Agriculture

Yanco

The aim of the project is to understand the factors which link minerals and quality in grains.

Progress

1. Manipulation of protein and minerals in rice grain

The consequences of raising protein content on grain size, amino acids, minerals, grain colour and cooking quality were examined by Ms Zara Evans, honours student, University of Sydney. As protein increased the mole % of amino acids changed as shown in Table 1.

Changes in amino acids are also being studied by Mrs Tina Dunn (technical officer) using a technique for culturing individual rice panicles detached post flowering. This facility was used to generate grains with proteins of only 3% (lower than found in commercial rice) to over 40% (N* 5.95). Most amino acid concentrations changed in the same order as observed in samples from the field (Table 1).

Table 1: Correlations between protein and amino acids in rice grain from two crops grown at Yanco Agricultural Institute in 1998-1999 and from cultured, detached panicles.

	cv. Jarrah from field	cv. Amaroo from field	cv. Amaroo cultured
Protein Range (%N x 5.95)	6.5 - 9.5	7.9 - 10.1	3.0 - 40.8
Alanine (Ala)	- ns	+ *	- ***
Threonine (Thr)	- ns	- *	- ***
Tyrosine (Tyr)	- ns	- *	+ **
Phenylalanine (Phe)	+ ***	+ ns	- ns
Aspartate +Asparagine (Asx D/N)	+ ns	+ ns	+ ***
Valine (Val)	+ *	+ ns	- **
Lysine (Lys)	- *	Unchanged	- ***
Methionine (Met)	- *	- ns	- ***
Proline (Pro)	- ***	Unchanged	- ***
Glysine (Gly)	- **	- ns	- ***
Histidine (His)	- ns	- *	- **
Leucine (Leu)	+*	+*	- ns
Glutamate + glutamine	+*	+*	+
Isoleucine (Ile)	+**	+*	- **
Arginine (Arg)	+ ns	- ns	- **
n =	8	4	36

- = negative and + = positive correlation against protein;

*, ** and *** = significant at P = 0.05, 0.01 and 0.001 level.

2. Importance of crop sowing technique on plant establishment and production (with Mr Yukihiro Hamada - Visiting Scientist, Japan)

In the first comparison in more than 20 years, 16 commercial crops which had been sown using aerial, sod and combine techniques were monitored in the 1998-1999 and 1999-2000 seasons. The establishment of sod sown crops was depressed by the presence of dry matter remaining from the previous pasture crop. Plant and grain samples have been prepared ready to determine N and mineral uptake patterns, yield and grain quality.

3. Low phytic acid rice

A mutant of the American rice Kaybonnet which has a high inorganic:phytic acid bound P ratio has been imported and grown in the glasshouse at Yanco. Ms Briony Wiltshire, a Year 4 Crop Science student from The University of Sydney is studying the impact of the low phytic acid trait on the mineral composition of the grain and the response to P supply.

Investigating links between minerals in rice grain and straighthead (2303)

Project Leader:

Mr Phillip Williams

Ricegrowers' Co-operative Limited

Leeton

The aim of the project is to find factors which cause straighthead and determine its impact on grain quality.

Progress

A survey was conducted to determine the extent and severity of straighthead in Australian rice crops.

In the 1998-1999 season samples were collected from patches of crop affected by straighthead and from apparently sound crop nearby. Some 30 crops were sampled. The patches of crop affected by straighthead had low harvest index ratios (grain weight:total shoot weight), but the apparently unaffected areas of crop had lower harvest index ratios than expected for good crops (Figure 9). This suggests that patches of straighthead are a visible indication of a problem which is actually reducing the yield of the whole or at least large areas of the crop by as much as 30%.

Figure 9. Comparison of the Harvest Index for crops sampled in the Straighthead Survey

The samples collected during the survey have been analysed to test for nutrient deficiencies (eg Table 2). While we are able to discount excessive manganese as a possible cause of the problem, no element has been identified as the cause of the problem.

Table 2. Summary of macro- and micro- elements in rice shoots at the panicle initiation stage of development (mg/kg)

# 1= unaffected crop, 9 = most severe symptoms of straighthead

In commercial crops straighthead is most commonly found in crops of long grain varieties such as Langi, and the short grain variety Koshihikari, especially when grown after pasture or a crop where the organic matter was incorporated.

In 2000 samples were again collected from crops with patches of straighthead and have been ground for chemical analysis. These will also be used to test the hypothesis that grain quality is affected by straighthead.

Arsenate residues from old orchard sites are also known to cause straighthead in the field. A technique, using the herbicide mono-sodium methylarsenate (MSMA), is being developed to screen varieties in the glasshouse at Yanco Agricultural Institute. When MSMA is applied at the 4-leaf stage symptoms of the disorder mimic those seen in the field. Varieties vary considerably in their response to MSMA. The mechanism of the disorder, however, may not be the same for varieties induced using MSMA as that which causes the problem in the field.

Straighthead in rice

2.4 Sustainable Crop Protection

Sub-Program Leader:

Dr Ric Cother

NSW Agriculture

Orange

Sustainable crop protection has a long-term aim of managing insect pests, diseases and weeds with minimal chemical usage. By understanding the biology of insects, weeds and plant pathogens, and their natural enemies, economically- and environmentally-sustainable crop protection can be achieved.

Host range and virulence of Rhynchosporium alismatis (2401)

Project Leader:

Dr Ric Cother

NSW Agriculture

Orange

Mr Wayne Pitt (PhD student) is working on this project which aims to expand the host range of this fungal pathogen to Arrowhead and Sagittaria graminae.

Progress

DNA from 50 fungal isolates was analysed using primers corresponding to repetitive DNA elements and simple sequence repeats. In addition, ITS regions for each isolate were amplified, sequenced and analysed using the Web-based phylogenetics program Web ANGIS. Results indicate minimal diversity within the fungal population (Figure 10). The majority of isolates are within the 95% similarity region, however, a small number of isolates including those obtained from Indonesia have segregated to provide some interesting differences. Thus far most of the variation can be linked to chance events throughout the history of the isolates.

Vegetative compatibility groups are presently being investigated to determine the likelihood of gene flow between different R. alismatis isolates to further reinforce the results obtained by DNA analysis. Concurrently, the infection process in Alisma plantago-aquatica, S. graminae and S. montevidensis is being studied by light and electron microscopy. Germination occurs 8-12 hours after inoculation, appressoria formation 16 hours, and attempted or successful penetration of the leaf surface sometime thereafter. There is some evidence of callous formation occurring approximately 40 hours after inoculation. This would indicate that the diseased area of the leaf results not from infection by the fungus but from a hypersensitive plant response aimed at preventing further tissue invasion.

Improving Crop Protection (2402)

Project Leader:

Dr Ric Cother

NSW Agriculture

Orange

This project consists of various sub-projects. A brief report on the two main sub-projects for 1999/2000 follows.

Risk assessment of exotic plant diseases to the Australian rice industry

Leader - Ric Cother, NSW Agriculture, Orange

Published epidemiological data on rice blast disease is being used by Mr Vincent Lanoiselet at CSU, Wagga to develop simulation and regional forecasting models to produce a risk analysis map for this disease, should it gain entry to southern NSW.

Long-term weather data is used to develop an analysis of the risk of the disease occurring in any particular year. The severity of the disease can also be modelled. If the parameters that determine the survival of the pathogen and the severity of the epidemics are well documented, the risk posed by rice blast to the NSW rice industry can be forecast.

Development of transformation protocols for Rhynchosporium alismatis

Leader - Gavin Ash, Charles Sturt University, Wagga Wagga.

There are additional members of the Family Alismataceae that are important weeds of rice including Sagittarius graminae and S. montevidensis on which the pathogen R. alismatis has minimal effect. The commercial attractiveness of the mycoherbicide would be increased if it attacked a wider range of species within the Alismataceae. The development of a transformation protocol for R. alismatis to allow the production of more aggressive isolates and a greater understanding of the constraints to a wider host range was undertaken by Dr Janet Taylor (National Research Council, Canada) in a project funded by the CRC.

During Dr Taylor's visit to Wagga Wagga (10 January 1999 - 1 May 2000) she developed a unique transformation system for R. alismatis using Rubidium chloride. The plasmid, pAN7-1, which induces hygromycin resistance in the transformants was integrated into the genome of the fungus. The successful integration was confirmed using southern analysis that also showed that the integration took place at a single location. This type of transformation system has not been reported previously in fungi.

Figure 10. ERIC-PCR fingerprint patterns of genomic DNA of Rhynchosporium alismatis (lanes 3-12; isolates RH58(E1), RH124(E1), RH123(E1), RH24(E1), RH62(E1), RH135(E1), RH147(E1), RH80(E2), RH125(E3) and RH126(E4)) and R.secalis W12868B(E5). The five electrophoretic patterns are shown in parentheses. Lanes 1 and 2 contain DNA molecular weight markers; the sizes are indicated in base pairs.

Sustainability of rice production systems (2405)

Project Leader:

Dr Mark Stevens

NSW Agriculture

Yanco

This project involves two postgraduate study programs, one being conducted by Ms Ayesha Burdett, a University of Melbourne honours student, and one by Ms Liesl Schiller, a student from the University of Sydney undertaking a Master of Science (Medicine) degree.

Progress

Ms Burdett completed her honours project in April 2000. Her project looked at the relative toxicity of barnyard grass herbicides to non-target aquatic invertebrates, both in the laboratory and in small plot field trials. Her results in the field using commercial rates of the three herbicides show that thiobencarb (Saturn®) has a strong adverse effect on crustaceans and chironomids, but that populations recover to control levels within five weeks of chemical application. Molinate (Ordram®) and clomazone (Magister®) are much more benign. More sensitive laboratory studies suggest that clomazone is probably the least harmful of the three compounds at commercial rates. Ms Burdett's project was supervised by Dr Mark Stevens, Yanco and Dr David MacMillan of the University of Melbourne.

Ms Schiller has completed the second year of her mosquito ecology work, and her results are currently being analysed. The vast majority of mosquitoes collected from rice fields and drainage systems belong to two species, Culex annulirostris and Anopheles annulipes. Larval densities in drains far exceed those in the fields or supply ditches. Adult mosquito emergence from the fields remains low until late December, and then increases substantially despite increasing populations of larval predators. This may be because predators are less efficient at controlling mosquito larvae as the crop density increases. Ms Schiller's project is being supervised by Dr Mark Stevens, Yanco and Assoc Prof Richard Russell of the University of Sydney (Westmead Hospital).

Ms Liesl Schiller, an MSc(Med) student who is researching the ecology of mosquitoes in rice fields and associated habitats.

Biodiversity assessment of MIA ricefields using stable isotope analysis (2406)

Project Leader:

Dr Mark Stevens

NSW Agriculture

Yanco

This PhD research project is being conducted by Ms Andrea Wilson through Charles Sturt University. The objective of the project is to identify differences in the spatial and temporal diversity of invertebrates in conventional and organic rice fields, and determine whether food web structure differs in the different invertebrate communities. The project is being supervised by Dr Mark Stevens, Yanco and Dr Robyn Watts of Charles Sturt University.

Progress

Processing of fauna samples from the 1998/1999 season has continued with the help of temporary staff at both Charles Sturt University and Yanco Agricultural Institute. Over 90 invertebrate morphospecies have been identified with more than 50% of samples sorted. This information is currently being used to establish a relational database for all results from the project.

During 1999/2000 further sampling of rice field invertebrates and their major food sources was undertaken. Three study sites were sampled on four occasions during the season. There have been substantial delays in getting these samples assessed, however arrangements are now in place to have the stable isotope analyses conducted at Edith Cowan University in Perth. The results will be available by June 2000.

The water scorpion Laccotrephes tristis, one of the more uncommon predators in NSW rice fields. It is not related to terrestrial scorpions.

Milestones

	Milestone	Year 1	Year 2	Year 3 1999/2000	Year 4	Year 5	Year 6	Year 7
2.1	Soil chemical & physical properties
	Appointment of Post Doctoral Fellow	X _
	Development of N soil test	X Commenced	X _	X _
	Appointment of technical officer	X Modified
	Soil acidity problem definition	X Acid Soils Program	X _	X _	X
	Definition of soil property damages	X Commenced	X _	X _	X	X	X	X
	Evaluation of aerial video as a tool			X _	X	X	X	X
	Definition of management factors affecting nutrient recovery			X _	X	X	X	X
	PhD project - spatial analysis	X Commenced	X _	X _	X	X	X	X
2.2	Environmental change
	Appoint Research Scientist	X _
	Define flowering test for cold resistance	X Commenced	X _	X _
	Confirm tolerance under field conditions	X Commenced	X Continuing	X Continuing	X
	Student projects	X One appointed	X _	X _	X
	Understanding cold and Nitrogen interaction	X Commenced	X _	X _	X	X
	Lipid metabolism	X Program modified	X Suspended - will recommence in Year 3 as modified project	X Suspended	X
	Understanding cellular response to cold	X Commenced	X _	X _	X
	Application of cold studies			X _	X	X	X	X
	Studies on climate change			X _	X	X	X	X
2.3	Mineral nutrition
	Appointment of staff	X Commenced	_		X
	Appointment of student	X Not achieved	_		X
	Review of factors affecting yield and quality	X Commenced	X _	X _
	Development of techniques	X Commenced	X _	X _
	Assess mineral changes	X Commenced	X _	X _
	Assess impact of yield improvement and management changes on mineral/quality relationships in rice and its relatives	X	X _	X _
	Determine mechanisms influencing translocation of minerals to grain			X Commenced	X	X	X	X
	Modify factors influencing quality in intensive rice growing			X Commenced	X	X	X	X
2.4	Sustainable crop protection
	Appointment of PhD student	X _			X
	Appointment of Honour students	X Replaced by visiting scientist			X
	Biology of Arrowhead and Water Plantain	X RIRDC projects	X RIRDC projects	X RIRDC projects
	Better understand biocontrol	X _	X _	X _
	Identification of dominant bloodworm species	X Commenced	X _
	Develop lab techniques for at least 1 additional Chironomid		X Commenced	X Commenced	X
	Evaluate Bti* transgenic lines		Staff appointed	X _	X	X	X	X
	Allelopathy	X With Program 3	X Program 3	X Program 3
	Progress towards identification of allelochemicals	X	X Program 3	X Program 3
	Improved pathogenicity of R.alismatis to Alismataceous weeds				X	X	X	X
	Phenology and host specificity of bloodworm species defined				X	X	X	X
	Integration of chemical and biological management of weeds				X	X	X	X
	Determination of susceptibility of major cultivars to exotic pests and diseases				X	X	X	X

* Bti= Bacillus thuringiensis, a bacterium with insecticidal properties.

X = To be completed (in some cases this exercise is spread over several years).

_= Achieved (if not achieved, status provided)