• to produce improved rice varieties for the NSW rice industry that are productive, reliable and 
• satisfy the requirements of domestic and international markets. 

Australian producers are efficient and obtain amongst the highest yields in the world but there is a continuing need to improve efficiency, competitiveness and to address some of the environmental concerns associated with rice production. Solutions to these problems include the development of more productive and adaptable varieties of shorter duration that have grain quality attributes that allow them to compete in the marketplace. It is also important that the seed produced by growers has the purity that will maintain productivity and quality.

• To improve the Tissue Testing Service used to predict the amounts of fertilizers to apply to rice crops.

In 1996/97, 1997/98 and 1998/99 comparisons were made at 33 sites to check the increase in yield per kg N when urea was topdressed in December, (2 to 3 weeks prior to PI), and at the PI stage.

Outcomes 

(1) NIR calibrations for total nitrogen, moisture, and starch in whole shoot samples were improved, 

(2) Calibrations for potassium, phosphorus and for zinc were developed.

(3) In collaboration with staff at RCL and NSW Agriculture annual revisions have been made to:-

(5) A database (the Rice Tissue Test Database) used to record all information on every sample sent for testing, and also to calculate the nitrogen uptake and fertilizer recommendations for each crop, has been revised in line with changes to the forms and recommendations mentioned above. This database has facilitated useful summaries of the information gathered from rice growers such as the influence of seasonal conditions on crop nitrogen and starch ratios, patterns of use of fertilizer, etc. These summaries have been invaluable to gaining a better understanding of the limits to rice production and for informing growers of best fertilizer management.

(6) Reduced pressure on the environment beyond the rice farm by reducing some of the wastage of fertilizers, eg in situations where inappropriate forms or amounts of fertilizer were applied.

(7) Guidelines for the N management of underfertilized crops prior to PI.

Value of the Rice NIR Tissue Test to the Industry

The RCL Rice Tissue Test, especially if used in conjunction with the maNage Rice software package, provides rice producers with relevant, accurate and economic information which aids in deciding the fertilizer program needed to achieve high rice grain yields through nitrogen fertilizer management. Additional benefits include analysis of the nitrogen:starch ratio which indications if a stress factor, other than nitrogen, is limiting the growth of the crop and the chance of obtaining the expected response to fertilizer nitrogen.

Implications 

• To determine if selected rice varieties display significant resistance to attack by Chironomus tepperi, and therefore whether incorporating bloodworm resistance into commercial varieties may be a viable method for reducing insecticide usage in the NSW rice industry.

ASREML analysis showed that YRK3, HR19, Goolarah and Koshihikari have higher levels of resistance than other varieties screened to date. The most resistant variety, YRK3, lost approximately one-third of its root tissue when exposed to moderate bloodworm infestations, indicating that it is probably not sufficiently resistant to be cultivated in the field without chemical protection.

Rearing final instar C.tepperi larvae through to pupation on either slightly resistant (WC1403, Koshihikari, Hungarian No. 1) or susceptible (Millin, Kyeema, Langi) varieties did not reveal any strong correlation between varietal resistance and pest survival or developmental times. Resistance in these varieties is apparently a form of antixenosis or ‘non-preference’.

A seed-mat technique was used to assess resistance of 11 selected varieties under field conditions during the 1997/8 rice season, however results from this trial were inconclusive due to the very low bloodworm populations at the trial site in that season.

Difficulties associated with maintaining bloodworm cultures in the laboratory during the later parts of summer 1997 and 1998 resulted in resources being temporarily redirected towards assessing the influence of fipronil seed treatments on the germination and early growth of rice.

• To evaluate impact compaction for its potential to reduce recharge from rice, and its effects on soil properties, rice crop productivity and profitability.

Research 

For impact compaction to be economic, the effect on infiltration needs to last for at least three seasons. The effect appeared to carry over to the second season at the one site where this could be determined.

Further investigations are also needed to refine guidelines for application of the technology, and to determine the longevity of the effect on infiltration.

The feasibility of using impact compaction, in conjunction with mole drains, to create a solution to both watertable problems and production limitations in rice-based cropping systems, should be explored.

Humphreys, E., Clark, R. and Beecher, G. (1998). Evaluation of compaction for reducing recharge from rice. Farmers’ Newsletter Large Area No. 150, 60-1.

Humphreys, E., Clark, R. and Beecher, G. (1998). Evaluation of impact compaction for reducing recharge from rice. Farmers’ Newsletter Large Area No. 152, in press.

Humphreys, E., Clark, R. and Beecher, G. (1998). Evaluation of compaction for reducing recharge from rice. Final Project Report to RIRDC. CSIRO Land and Water Consultancy Report No. 98-38.

• To determine, across a range of soil types and watertable conditions, the effect of increasing the irrigation water salinity on the infiltration beneath the rice crop.

• To determine the potential for use of groundwater within a rice rotation.

Background:

There is concern that increasing the farm supply water salinity could result in a significant increase in deep drainage especially from the rice phase. Laboratory studies have shown that clay soils become more permeable as the salinity of the supply water increased, however, the practical significance of this effect within rice based production systems has not been evaluated. The other strategy for groundwater pumping is to use the groundwater solely within the farm, mixed with on-farm channel supplies.

Rice rotation experiment. 

The long term effects of irrigating with saline groundwater on soil salinity, infiltration, and crop productivity are being evaluated within a rice - fallow - wheat - sub clover - rice rotation. The site was designed such that each phase of the rotation occurs each year in a separate block allowing seasonal effects on irrigation management to be assessed. Groundwater from a shallow spearpoint is applied to both the wheat and sub clover phases with channel supply water being used to grow the following rice crop. The experiment commenced in 1991 and will conclude in 2000 with each block having completed 2 cycles of the 4 year rotation.

Rice rotation experiment. Irrigating with groundwater of 4.5 dS/m has not reduced wheat yields. Sub clover production, particularly in the autumn, was reduced by irrigating with groundwater salinities of 2 and 3 dS/m. Rice yield was not affected by irrigating the previous wheat - sub clover phases with groundwater except following the 1993-94 drought.

Use of groundwater on the wheat - sub clover phase increased soil salinity to at least 1.5 m deep. Rice was effective in leaching the rootzone to an acceptable level of salinity for the following crops, however, sodium remained at an elevated level.

• Reduced groundwater recharge by removing "leaky" soils from rice production through the development of electromagnetic (EM) procedures to rapidly assess the suitability of soil for rice growing and eliminate the need for physical soil sampling.

Background:

Research 

Outcomes 

A three-stage classification scheme was developed:

1. Include the soil if the EM31 measurement is equal to or greater than 150 mS/m
2. Include the soil if the ESP of the top 60 cm of the soil is greater than 6 
3. Include the soil if the ESP of the depth increment between 60 and 150 cm is greater than 12.
4. Exclude all other soils.

Implications 

Adopting these changes to rice policy will allow better definition of the area of soil which contributes significantly to ground water accessions. This will reduce the area of land ‘retired’ from rice growing, and better define land requiring remedial soil treatments. Implementing these research methods as an operational soil classification system will allow more appropriate and environmentally sustainable use of soil and water resources.

Accurate identification of land suitable for ricegrowing would provide benefit for individual landholders by: (i) optimising farm development/redevelopment avoiding costly development of unsuitable land, (ii) reducing water use - savings could be in the order of $50/ha where water use is excessive, (iii) increasing the flexibility of farm management by increasing the availability of water. However some growers may be impacted negatively by the implementation of such soil classification changes.

Research findings will be rapidly adopted within Land and Water Management Plans. These plans already endorse the need to improve the way soil is assessed for ricegrowing.

Publications

Iain Hume, Geoff Beecher, Brian Dunn and Bruce Hammond (1998). EM to estimate groundwater recharge from ricegrowing. IREC Farmers’ Newsletter, No 152 Large Area pp 70-71.6

PMB

YANCO NSW 2703

PO Box 108

FINLEY NSW 2713

• To improve the quality of paddy rice, in particular the percentage of whole grain after milling, through the adoption of appropriate crop management technology and practices. through:

• Identifying the management practices in commercial ricegrowing that most effect rice grain quality, in particular % whole grain.
• Identifying the barriers and constraints to the adoption of management practices to improve grain quality.
• Develop and implement a rice extension program to encourage the transfer and adoption of rice management technology that maximises rice grain quality.

Background:

Genetic and environmental factors were generally accepted as major determinants of grain quality, including the % whole grain after milling. Grower management factors have a major affect within these limits, but were poorly understood and accepted by growers.

Research 

The resulting extensive database represented some 433 commercial rice crops from all ricegrowing regions, 3630 individual grain samples from 8 - 10 weekly harvests from late February to early June. 

Focus discussion groups with ricegrowers were held in each Agronomy District to survey the knowledge, attitudes and constraints on achieving high % whole grain. The organised and structured extension network of NSW Agriculture was used to promote the results of the project.

Outcomes 

The survey found that growers were poorly informed about grain quality issues and that experience made them sceptical of the value of recommended practices. Their attitudes to grain quality management were affected by the limited returns for delivering improved quality grain compared to the increased costs of compliance, which were often affected by industry policies on receival, particularly moisture limits. 

The results of the % whole grain analysis were extended widely to ricegrowers through meetings, field days and publications. Adoption of the recommendations is limited by perceived limited returns and increased costs of adoption of recommended practices.

Implications 

Our knowledge and understanding of the processes and practices affecting % whole grain results have been greatly improved by the study. There is an opportunity to further analyse the data to define the environmental and management framework affecting % whole grain, and to further explore the response of long grain varieties and the impact of rainfall events. Further research and investigation needs should be considered.

Future extension recommendations and programs will not be successful without consideration of the impact on other factors on the ability and willingness of ricegrowers to adopt the practices necessary to consistently harvest and deliver high quality grain. In particular, the industry objectives and needs 

for improved quality must be balanced with appropriate premiums and delivery moisture policies.